{"id":13,"slug":"13-tesamorelin-gln-8-aib-2-aminoisobutyric-acid-substitution","title":"Tesamorelin Gln-8 → α-aminoisobutyric acid (Aib) to stabilize N-terminal helix","status":"DISCARDED","fold_verdict":"DISCARDED","discard_reason":null,"peptide":{"name":"Tesamorelin","class":"PERFORMANCE","sequence":"YADAIFTNSYRKVLGQLSARKLLQDIMSRQQGESNQERGARARL","modified_sequence":"YADAIFT(Aib)SYRKVLGQLSARKLLQDIMSRQQGESNQERGARARL","modification_description":"Gln-8 → Aib (2-aminoisobutyric acid) substitution"},"target":{"protein":"Growth hormone-releasing hormone receptor","uniprot_id":"Q02643","chembl_id":"CHEMBL2049","gene_symbol":"GHRHR"},"rationale":{"hypothesis":"We hypothesize that substituting Gln-8 with α-aminoisobutyric acid (Aib) in Tesamorelin will reinforce the N-terminal α-helix that engages the GHRHR extracellular domain, increasing receptor binding affinity and proteolytic stability without altering the trans-3-hexenoyl-protected N-terminus. Aib's geminal dimethyl group is a well-characterized helix inducer and should pre-organize residues 1-13 into the bioactive conformation. This is a different chemistry and position from prior DPP-IV-blocking N-terminal strategies (D-Ala-2 in Sermorelin discarded; N-methyl-Aib in Ipamorelin refined).","rationale":"GHRH analogues bind GHRHR via an amphipathic N-terminal α-helix (residues ~1-13); Gln-8 sits on the solvent-exposed face and is non-essential for receptor contact, making it an ideal site for a helix-stabilizing residue swap. Aib restricts φ/ψ angles to helical values (Ramachandran bias toward -60°/-45°), and Aib-for-Gln substitutions in related peptides (e.g., GHRH(1-29) analogues, glucagon, GLP-1) have improved both helicity and metabolic stability. Because the trans-3-hexenoyl group already protects the N-terminus from DPP-IV, this modification targets a complementary stability axis (conformational rigidity) rather than re-attempting N-terminal protease blockade.","predicted_outcome":"Structure prediction should show increased helical content across residues 4-13 with higher pLDDT (>0.85) in this segment compared to wild-type Tesamorelin, and preserved overall fold geometry consistent with GHRHR engagement.","mechanism_class":null,"biohacker_use":null},"confidence":{"plddt":0.491517573595047,"ptm":0.4410421550273895,"iptm":0.3404698967933655,"chai_agreement":null,"chai1_gated_decision":"SKIPPED_LOW_CONFIDENCE","binding_probability":null,"binding_pic50":null,"predicted_binding_change":null},"profile":{"aggregation_propensity":0.193,"stability_score":0.203,"bbb_penetration_score":0.011,"half_life_estimate":"long (>6 hours, depends on modifications)"},"narrative":{"tldr":"Fold №13 tests whether substituting Gln-8 with the helix-inducing non-proteogenic amino acid Aib in Tesamorelin can pre-organize the N-terminal α-helix for improved GHRHR engagement and proteolytic stability. The structure prediction returned a peptide pLDDT of 0.49 and an ipTM of 0.34, indicating low backbone confidence and an unreliably resolved docking pose — insufficient to confirm or deny the helix-reinforcement hypothesis. The predicted outcome of pLDDT >0.85 in residues 4–13 was not achieved, and no measurable binding signal was produced. The modification hypothesis remains mechanistically coherent but computationally intractable with the current toolchain.","detailed_analysis":"Tesamorelin is a 44-residue synthetic analogue of human GHRH(1-44), distinguished by its trans-3-hexenoyl N-terminal cap, which protects against DPP-IV cleavage at the Tyr-1/Ala-2 bond. It is the only FDA-approved therapy for HIV-associated lipodystrophy and operates through direct GHRHR engagement to stimulate pulsatile GH secretion and reduce visceral adipose tissue. The clinical literature consistently establishes its efficacy across multi-year trials, including on modern integrase inhibitor-based ART regimens, confirming the GHRHR pathway as robustly druggable. This fold attempts to build on tesamorelin's already-solid pharmacological foundation by addressing a second, complementary axis of optimization: conformational rigidity of the N-terminal helix.\n\nThe structural rationale for this distillation is grounded in the well-established role of the N-terminal α-helix (approximately residues 1–13) in GHRH receptor engagement. The amphipathic character of this region drives productive contacts with the GHRHR extracellular domain, and disruption of helical geometry attenuates potency. Position 8 (Gln) sits on the solvent-exposed face of this helix and is not known to make direct receptor contacts, making it a structurally logical site for a helix-stabilizing substitution. Aib's geminal dimethyl group on the α-carbon enforces φ/ψ dihedral angles within the canonical α-helical region, and its helix-inducing properties are extensively validated across peptide chemistry literature. The hypothesis is that pre-organizing residues 1–13 into the bioactive conformation would reduce entropic costs of receptor binding and potentially slow mid-helix proteolytic attack.\n\nThis modification is intentionally distinct from prior strategies explored in the lab. The Sermorelin D-Ala-2 fold (Fold №2, DISCARDED, pLDDT 0.49) targeted DPP-IV blockade via stereochemical inversion at the N-terminus — a strategy already addressed in tesamorelin by the trans-3-hexenoyl cap itself. The Ipamorelin N-Me-Aib fold (Fold №4, REFINED, pLDDT 0.80) demonstrated that Aib-class chemistry is compatible with GH-axis receptor engagement and can yield high-confidence predicted structures in a related peptide class. Fold №13 sought to apply similar conformational logic to a mid-helix position in a longer, clinically validated peptide, targeting a different stability axis entirely.\n\nThe structure prediction results, however, were not informative. The peptide pLDDT of 0.491 is virtually identical to the Sermorelin D-Ala-2 result and sits well below the threshold for confident backbone placement. The ipTM of 0.34 indicates the predicted peptide-receptor interface pose is not reliably resolved — the model does not converge on a stable docking geometry. No Chai-1 agreement data or Boltz-2 affinity values were produced, removing the secondary confidence checks that would ordinarily be used to triangulate a weak primary signal. The predicted outcome of pLDDT >0.85 across residues 4–13 was not achieved by any metric.\n\nThe heuristic sequence-based property profile offers modest contextual data but does not rescue the verdict. A stability score of 0.203 and aggregation propensity of 0.193 suggest the modified sequence is not flagged for gross stability failures, and the half-life estimate remains long — consistent with the trans-3-hexenoyl cap's known protective effect. BBB penetration of 0.011 is expected and irrelevant for a GH-axis peripheral peptide. These heuristics confirm the Aib substitution does not appear to introduce catastrophic sequence-level liabilities, but they cannot substitute for structural confidence.\n\nThe core difficulty of this fold is that a 44-residue peptide complexed with a class B GPCR is at the upper edge of what current single-run structure prediction tools can reliably resolve. The GHRHR lacks a published high-resolution co-crystal structure with tesamorelin or native GHRH that would provide a template for confident prediction. The low pLDDT likely reflects genuine model uncertainty about the peptide's conformation in the bound state rather than a signal that the modification is structurally disruptive — but these two interpretations are indistinguishable with the data in hand. This is a tool limitation, not a biological verdict.\n\nFrom a medicinal chemistry perspective, the Gln-8 → Aib substitution remains a mechanistically plausible hypothesis. The key unresolved trade-off — whether the loss of Gln's hydrogen-bonding capacity to GHRHR outweighs the gain in helical pre-organization — cannot be adjudicated computationally at this time. The literature is entirely silent on position-8 SAR in tesamorelin or close analogues, and no high-resolution structural data on the tesamorelin–GHRHR complex exists to anchor computational models. Wet-lab approaches, particularly circular dichroism to confirm helicity gains and receptor binding assays against GHRHR, are the appropriate next steps if this hypothesis is to be advanced.\n\nIn the broader lab narrative, Fold №13 joins Fold №2 (Sermorelin D-Ala-2) as a case where a mechanistically sound hypothesis applied to a longer or more complex peptide returns a low-confidence structural prediction. Both returned pLDDT ≈ 0.49 and uninformative ipTM values. This pattern suggests a systematic limitation: the current toolchain may not be well-suited to resolving mid-helix non-proteogenic substitutions in 40+ residue peptides complexed with class B GPCRs without either ensemble prediction or a high-quality structural template. The positive contrast remains Fold №4 (Ipamorelin, 5-mer, REFINED), where a shorter peptide with a simpler receptor context yielded a pLDDT of 0.80 and a confident verdict.","executive_summary":"Tesamorelin Gln-8→Aib: pLDDT 0.49, ipTM 0.34 — below confidence threshold for any structural verdict. The helix-stabilization hypothesis is mechanistically coherent but computationally intractable at this peptide length and receptor class with the current toolchain.","tweet_draft":"DISTILLATION №13 — discarded.\nTesamorelin, Gln-8 → Aib helix stabilization.\npLDDT 0.49 | ipTM 0.34 — model uncertainty, not a biological verdict.\nThe hypothesis survives. The tools don't resolve it yet.\nIn silico only. Full report: alembic.bio","research_brief_markdown":"# FOLD №13 — Tesamorelin Gln-8 → Aib Helix Stabilization\n**Verdict: DISCARDED** | Peptide: Tesamorelin | Class: Performance | Target: GHRHR (Q02643)\n\n---\n\n## Mechanism of action (background)\n\nTesamorelin is a synthetic 44-residue analogue of human GHRH(1-44), modified at the N-terminus with a trans-3-hexenoyl group to protect against DPP-IV cleavage at the Tyr-1/Ala-2 bond. It is the only FDA-approved GHRH analogue, indicated for HIV-associated lipodystrophy, and acts by binding to the growth hormone-releasing hormone receptor (GHRHR, UniProt Q02643) on somatotroph cells of the anterior pituitary, stimulating pulsatile GH secretion. Downstream GH and IGF-1 signaling drives lipolysis, preferentially reducing visceral adipose tissue. Efficacy has been demonstrated across multiple Phase III trials and 52-week extension studies, including on modern integrase inhibitor-based ART (Russo et al. 2024), confirming the robustness of the GHRHR pathway as a pharmacological target.\n\nThe molecular basis of GHRHR engagement depends critically on the amphipathic α-helical conformation of residues approximately 1–13 of GHRH/tesamorelin. This N-terminal helix presents a hydrophobic face for receptor contact and a solvent-exposed face of polar residues. Disruption of helical geometry in this region attenuates receptor potency. The trans-3-hexenoyl cap provides both proteolytic protection and potential conformational stabilization at the N-terminus — but the mid-helix region (residues 4–13) remains flexible in solution and may adopt the bioactive conformation only upon receptor encounter, incurring an entropic binding penalty.\n\n---\n\n## Modification hypothesis (what we tested)\n\nThis distillation tested whether substituting Gln-8 with α-aminoisobutyric acid (Aib) could pre-organize residues 1–13 of Tesamorelin into the bioactive α-helical conformation, reducing the entropic cost of GHRHR binding and potentially adding a second axis of proteolytic protection via conformational rigidity at a mid-helix site.\n\n**Modified sequence:** YADAIFT**(Aib)**SYRKVLGQLSARKLLQDIMSRQQGESNQERGARARL\n\nThe rationale was multi-layered:\n- Gln-8 sits on the **solvent-exposed face** of the N-terminal helix and is not known to make direct receptor contacts, making it a structurally permissive site for substitution.\n- Aib's **geminal dimethyl group** on the α-carbon sterically enforces φ/ψ dihedral angles within the canonical α-helical region (approximately −60°/−45°), and its helix-inducing properties are extensively validated in peptide chemistry literature.\n- Aib-type chemistry has direct precedent in GH-axis peptides: **Fold №4 (Ipamorelin N-Me-Aib, REFINED, pLDDT 0.80)** demonstrated that Aib-class substitutions are compatible with GH secretagogue receptor engagement and yield high-confidence predicted structures in a related peptide.\n- This strategy is **chemically and positionally distinct** from the DPP-IV-blocking N-terminal approaches tested in Fold №2 (Sermorelin D-Ala-2, DISCARDED) and is orthogonal to the trans-3-hexenoyl cap already present in tesamorelin — targeting conformational rigidity rather than exopeptidase blockade.\n\nThe predicted outcome was pLDDT >0.85 across residues 4–13 with preserved overall fold geometry.\n\n---\n\n## Why the prediction was uninformative (technical analysis of the metrics)\n\nThe structure prediction returned metrics that preclude any confident interpretation:\n\n| Metric | Value | Threshold for confidence |\n|---|---|---|\n| Peptide pLDDT | **0.491** | >0.70 for moderate, >0.85 for high |\n| pTM | 0.441 | >0.60 for moderate confidence |\n| ipTM | **0.340** | >0.60 for reliable interface |\n| Chai-1 agreement | None | — |\n| Boltz-2 affinity | Not produced | — |\n\nThe pLDDT of 0.491 indicates substantial uncertainty in backbone placement throughout the 44-residue analogue — the model cannot confidently assign secondary structure elements, including the very N-terminal helix that is the subject of the hypothesis. The ipTM of 0.34 means the predicted peptide-receptor docking pose is not reliably resolved; the interface geometry cannot be trusted. The absence of Chai-1 agreement and Boltz-2 affinity values removes the secondary confidence checks that would ordinarily triangulate a weak primary signal.\n\nNotably, this pLDDT value is nearly identical to **Fold №2 (Sermorelin D-Ala-2, pLDDT 0.49, DISCARDED)** — suggesting a systemic pattern rather than a modification-specific failure. Both folds involved non-proteogenic substitutions in longer GHRH-class peptides complexed with GHRHR. The contrast with **Fold №4 (Ipamorelin, pLDDT 0.80, REFINED)** — a shorter pentapeptide GHS targeting GHSR — is instructive: peptide length and template availability appear to substantially influence prediction reliability in this receptor class.\n\nThe heuristic sequence-based properties (aggregation propensity 0.193, stability score 0.203, long half-life estimate) suggest no gross sequence-level liabilities were introduced by the Aib substitution, but these cannot substitute for structural confidence.\n\n**Critical distinction:** A pLDDT of 0.49 does not mean the modification is structurally disruptive. It means the model is uncertain — the two interpretations (modification causes structural disruption vs. model lacks template fidelity for this complex) are indistinguishable with the data in hand. The GHRHR lacks a published high-resolution co-crystal structure with tesamorelin or native GHRH, depriving the prediction model of the template quality needed to confidently resolve a 44-residue peptide at a class B GPCR interface.\n\n---\n\n## What this tells us (negative results are data)\n\nFold №13 does not falsify the Gln-8 → Aib hypothesis. It establishes that **this hypothesis cannot be evaluated with single-run structure prediction at the current state of the toolchain** for this peptide-receptor system. That is a meaningful, if frustrating, result.\n\nSpecifically, this fold rules out the possibility of obtaining a high-confidence computational endorsement of the helix-preorganization strategy for tesamorelin using the current pipeline. It also narrows the design space: any computational approach to tesamorelin SAR at internal helix positions will require either (a) a high-resolution structural template for the tesamorelin–GHRHR complex, (b) ensemble prediction methods that can average over conformational uncertainty, or (c) fragment-based approaches that model the N-terminal helix independently before docking.\n\nThe key mechanistic trade-off — whether Aib's helix-inducing effect outweighs the loss of Gln-8's hydrogen-bonding capacity to GHRHR residues — remains entirely unresolved. The literature is silent on position-8 SAR in any GHRH analogue, meaning this is a genuine knowledge gap rather than a resolved question with a negative answer.\n\nIn the context of the lab's emerging pattern: Folds №2 and №13 both returned pLDDT ≈ 0.49 on GHRHR-targeting peptides ≥29 residues. Fold №4 (Ipamorelin, 5-mer, GHSR target) returned pLDDT 0.80. This pattern suggests the lab should either (1) focus computational GHRH work on shorter, truncated analogues (GHRH(1-17) or GHRH(1-29) fragments) where prediction confidence may be recoverable, or (2) escalate to ensemble/multi-model approaches before investing further single-run credits on full-length tesamorelin variants.\n\n---\n\n## Alternative hypotheses to test (avoid the failure mode)\n\n**Computational approaches to recover signal:**\n- **Truncated analogue:** Test Aib-8 in a GHRH(1-17) or GHRH(1-29) framework — shorter peptides yield higher pLDDT in this receptor class, and SAR mapping in truncated analogues is standard practice in the GHRH literature.\n- **Ensemble prediction:** Run 5–10 predictions with different random seeds and report mean/SD pLDDT and ipTM; ensemble agreement would provide a confidence interval on the structural uncertainty.\n- **Fragment modeling:** Model the N-terminal helix (residues 1–13) in isolation to assess whether Aib-8 measurably increases helical propensity before attempting full complex docking.\n- **Alternative helix-inducing substitutions at position 8:** α-methyl-phenylalanine (MePhe) or L-α-methyl-glutamine could probe whether steric reinforcement at the α-carbon is the operative variable while partially preserving side-chain character.\n\n**Wet-lab validation path (if hypothesis is to be advanced):**\n- **Circular dichroism (CD) spectroscopy:** Direct measurement of helical content in the Aib-8 analogue vs. native tesamorelin — the most direct test of the helix-preorganization hypothesis.\n- **GHRHR binding assay (competitive radioligand or TR-FRET):** Measures affinity change independently of structural confidence; would resolve the Aib vs. Gln trade-off question computationally intractable here.\n- **Plasma stability assay:** Incubation in human plasma with HPLC/MS quantification would determine whether mid-helix Aib confers proteolytic protection beyond what the trans-3-hexenoyl cap already achieves.\n- **NMR (solution structure):** Would directly confirm or deny helical preorganization in the N-terminal segment — gold standard for the conformational hypothesis.","structural_caption":"The predicted Tesamorelin[Gln8Aib]-GHRHR complex shows low overall structural confidence, with a peptide pLDDT of 0.49 indicating substantial uncertainty in backbone placement throughout the 44-residue analogue. The interface metric (ipTM 0.34) suggests the peptide-receptor docking pose is not reliably resolved. No measurable enhancement of helical pre-organization in the 4-13 segment can be confirmed from these metrics, and the predicted outcome of pLDDT >0.85 in that region was not achieved.","key_findings_summary":"Tesamorelin (TH9507) is a synthetic analogue of human growth hormone-releasing hormone (GHRH) distinguished by its trans-3-hexenoyl modification at the N-terminus, which confers proteolytic stability compared to native GHRH(1-44). It is the only FDA-approved therapy for HIV-associated lipodystrophy, demonstrating robust reductions in visceral adipose tissue (VAT) in Phase III randomized controlled trials and maintained efficacy through 52-week extension studies. The clinical literature (Dhillon 2011, Spooner & Olin 2012, Wang & Tomlinson 2009) consistently establishes that tesamorelin's mechanism depends on intact GHRHR engagement to stimulate pulsatile GH secretion, thereby mobilizing visceral fat. Recent data (Russo et al. 2024) confirm efficacy is preserved on modern integrase inhibitor-based ART regimens, underscoring the robustness of the molecule's pharmacodynamic mechanism.\n\nThe structural pharmacology of tesamorelin relevant to our hypothesis centers on the known importance of the N-terminal α-helix (approximately residues 1–13) of GHRH for productive engagement with the extracellular domain of GHRHR. Native GHRH adopts an amphipathic α-helical conformation upon receptor binding, and disruption of helical geometry in this region attenuates potency. The trans-3-hexenoyl N-terminal cap in tesamorelin was specifically designed to protect against DPP-IV cleavage at the Tyr-1/Ala-2 bond while potentially stabilizing helical propensity — a rationale analogous to, but chemically distinct from, D-Ala-2 substitution strategies explored in sermorelin derivatives. The literature does not directly address Gln-8 contributions, but position 8 sits within the core of the N-terminal helix, making it a structurally plausible site for conformational reinforcement.\n\nAib (α-aminoisobutyric acid, 2-aminoisobutyric acid) is a well-established helix-inducing non-proteogenic amino acid whose geminal dimethyl group sterically enforces backbone dihedral angles (φ, ψ) within the α-helical region. Its incorporation into peptide helices is extensively validated in the broader peptide chemistry literature, and it has been exploited in GH secretagogues — notably ipamorelin, where N-methyl-Aib (α-aminoisobutyric acid in the N-methylated form) contributes to conformational preorganization and resistance to exopeptidases. The hypothesis that substituting the glutamine at position 8 with Aib would pre-organize residues 1–13 into the bioactive helical conformation is mechanistically coherent with established Aib stereochemical properties, though direct experimental evidence for this specific substitution in tesamorelin is absent from the available literature.\n\nThe sports medicine and gray-market peptide literature (Mendias & Awan 2025/2026) contextualizes tesamorelin as an approved reference compound within a broader landscape of GHRH-axis peptides, noting that gray-market tesamorelin samples show significant purity variability (41–71% failure rates against regulatory standards), which reinforces the need for well-characterized analogues with improved stability. These preprints provide no mechanistic data relevant to the Gln-8→Aib hypothesis but do confirm the therapeutic relevance of improving tesamorelin's pharmacological profile. The COVID-19 network pharmacology preprint (López-Cortés et al. 2020) is not relevant to the hypothesis.\n\nOverall, the literature strongly supports tesamorelin's clinical utility and validates the GHRHR as the relevant target, but is largely silent on structure-activity relationships at individual helical positions, particularly position 8. The hypothesis is supported by general principles of Aib helix-induction chemistry and the precedent of conformational stabilization strategies in related GHRH/GHS peptides, but lacks direct experimental validation specific to tesamorelin."},"structured":{"known_activity":null,"known_binders":null,"candidate_variants":null,"domain_annotations":null,"literature_context":{"pubmed":[{"pmid":"38905488","title":"Efficacy and safety of tesamorelin in people with HIV on integrase inhibitors.","abstract":"OBJECTIVE: Tesamorelin is the only FDA-approved therapy to treat abdominal fat accumulation in people with HIV (PWH). Phase III clinical trials were conducted prior to the introduction of integrase inhibitors (INSTIs), which are now a mainstay of HIV antiretroviral therapy.\n\nDESIGN: We leveraged a randomized double-blind trial of 61 PWH and metabolic dysfunction-associated steatotic liver disease to evaluate the efficacy and safety of tesamorelin 2 mg once daily vs. identical placebo among participants on INSTI-based regimens at baseline.\n\nMETHODS: In the parent clinical trial, visceral fat cross-sectional area, hepatic fat fraction, and trunk-to-appendicular fat ratio were quantified using magnetic resonance imaging, proton magnetic resonance spectroscopy, and dual-energy x-ray absorptiometry, respectively, at baseline and 12 months. Metabolic and safety outcomes were compared between treatment arms.\n\nRESULTS: Among 38 participants on INSTI-based regimens at baseline, 15 individuals on tesamorelin and 16 individuals on placebo completed the 12-month study. Tesamorelin led to significant declines in visceral fat (median [interquartile range]: -25 [-93, -2] vs. 14 [3, 41] cm 2 , P  = 0.001), hepatic fat (-4.2% [-12.3%, -2.7%] vs. -0.5% [-3.9%, 2.7%], P  = 0.01), and trunk-to-appendicular fat ratio (-0.1 [-0.3, 0.0] vs. 0.0 [-0.1, 0.1], P  = 0.03). Tesamorelin was well tolerated with a similar frequency of adverse events, including hyperglycemia, between groups.\n\nCONCLUSIONS: The current analysis provides the first dedicated data on the efficacy and safety of tesamorelin among PWH on INSTI-based regimens. Despite the association of INSTI use with weight gain and adipose tissue dysfunction, tesamorelin had beneficial effects on body composition with no exacerbation of glycemic control.","authors":["Russo Samuel C","Ockene Mollie W","Arpante Allison K","Johnson Julia E","Lee Hang","Toribio Mabel","Stanley Takara L","Hadigan Colleen M","Grinspoon Steven K","Erlandson Kristine M","Fourman Lindsay T"],"year":2024,"journal":"AIDS (London, England)"},{"pmid":"21283099","title":"Tesamorelin.","abstract":"In November 2010, tesamorelin (Egrifta; Theratechnologies/EMD Serono), a growth hormone-releasing factor analogue, was approved by the US Food and Drug Administration for the reduction of excess abdominal fat in HIV-infected patients with lipodystrophy.","authors":["Grunfeld Carl","Dritselis Argyris","Kirkpatrick Peter"],"year":2011,"journal":"Nature reviews. Drug discovery"},{"pmid":"22298602","title":"Tesamorelin: a growth hormone-releasing factor analogue for HIV-associated lipodystrophy.","abstract":"OBJECTIVE: To evaluate the efficacy and safety of tesamorelin, a growth hormone releasing factor analogue approved by the Food and Drug Administration in November 2010 for the treatment of lipodystrophy associated with HIV infection.\n\nDATA SOURCES: Literature was obtained through MEDLINE (1948-November 2011) and International Pharmaceutical Abstracts (1970-October 2011) using the search terms tesamorelin, TH9507, growth hormone releasing factor, and HIV-associated lipodystrophy syndrome. Additional publications were obtained through review of references within primary literature publications as well as pertinent Web sites.\n\nSTUDY SELECTION AND DATA EXTRACTION: All articles published in English identified from the data sources were evaluated and all pertinent information was included. All studies relevant to the evaluation of efficacy and safety of tesamorelin in the management of HIV-associated lipodystrophy were included, with a focus on trials completed in humans.\n\nDATA SYNTHESIS: In 2 Phase 3 clinical trials and their pooled analyses, tesamorelin was proven to significantly decrease waist circumference and visceral adipose tissue (VAT) following 26 weeks of treatment. Both trials also demonstrated significant improvements in some subjective body image parameters. Both studies had 26-week extension phases that confirmed maintenance of VAT improvements on treatment without adverse impact on blood glucose and lipid parameters. Limited data support off-label uses of tesamorelin at this time.\n\nCONCLUSIONS: Tesamorelin is effective in improving visceral adiposity and body image in patients with HIV-associated lipodystrophy over 26-52 weeks of treatment. Potential limitations for its use include high cost and lack of long-term safety and adherence data. Tesamorelin provides a useful treatment option for management of patients with significant lipodystrophy related to HIV infection.","authors":["Spooner Linda M","Olin Jacqueline L"],"year":2012,"journal":"The Annals of pharmacotherapy"},{"pmid":"21591600","title":"Tesamorelin update.","abstract":"","authors":["O'Neal Reilly"],"year":2010,"journal":"BETA : bulletin of experimental treatments for AIDS : a publication of the San Francisco AIDS Foundation"},{"pmid":"21668043","title":"Tesamorelin: a review of its use in the management of HIV-associated lipodystrophy.","abstract":"Tesamorelin (Egrifta™) is a synthetic analogue of human growth hormone-releasing hormone (also known as growth hormone-releasing factor) that stimulates the synthesis and release of endogenous growth hormone. It is the first and, so far, only treatment indicated for the reduction of excess abdominal fat in patients with HIV-associated lipodystrophy. This article reviews the pharmacological properties, clinical efficacy and tolerability of tesamorelin in patients with HIV-associated central fat accumulation. Subcutaneous tesamorelin was effective in reducing visceral adipose tissue (VAT), but did not affect subcutaneous adipose tissue to a clinically significant extent in two 26-week, well designed, clinical trials in patients with HIV-associated central fat accumulation. This reduction in VAT was maintained in the longer term in patients who continued to receive tesamorelin until week 52 in the extension phases of the two trials. However, discontinuation of therapy during this period resulted in the reaccumulation of VAT. Tesamorelin therapy was also associated with significant improvements in other body composition measures (e.g. trunk fat and waist circumference) and improvements were generally seen in some body image parameters (e.g. belly image distress). Tesamorelin was generally well tolerated, with treatment-emergent serious adverse events occurring in <4% of patients during 26 weeks of therapy. Most of these events were injection-site reactions or events known to be associated with growth hormone therapy (e.g. arthralgia, headache and peripheral oedema). Although long-term clinical experience is needed to further assess the benefits and risks of therapy, current evidence suggests that tesamorelin may be useful for reducing visceral adiposity in patients with HIV-associated lipodystrophy, thereby potentially improving self image.","authors":["Dhillon Sohita"],"year":2011,"journal":"Drugs"},{"pmid":"19243281","title":"Tesamorelin, a human growth hormone releasing factor analogue.","abstract":"BACKGROUND: The combination of clinical effectiveness with a variety of adverse side effects from the use of recombinant human growth hormone (rhGH) in therapy for growth hormone (GH)-deficient disorders has led to the development of human growth hormone releasing factor (GFR) analogues, which may be better tolerated. Tesamorelin, a synthetic GFR, has been developed as a potential treatment for a variety of conditions that may be associated with a relative deficiency of GH including HIV-related lipodystrophy.\n\nOBJECTIVE: This article reviews the development of tesamorelin and its purported role in HIV-related lipodystrophy and other potential indications.\n\nMETHODS: Relevant articles and abstracts were obtained from searches of the medical and chemical literature databases and the references from published articles.\n\nRESULTS/CONCLUSION: A multicenter, randomized, placebo-controlled, Phase III clinical trial suggested that tesamorelin might be a beneficial treatment strategy for HIV-related lipodystrophy with a good safety profile and a positive effect on reducing visceral fat. Other potential indications for tesamorelin appear less promising from the current data.","authors":["Wang Ying","Tomlinson Brian"],"year":2009,"journal":"Expert opinion on investigational drugs"}],"biorxiv":[{"pmid":"","doi":"10.20944/preprints202512.1011.v3","title":"Safety and Efficacy of Approved and Unapproved Peptide Therapies for Musculoskeletal Injuries and Athletic Performance","abstract":"Peptides are short chains of amino acids with a unique pharmacological niche between small-molecule drugs and large proteins. Their use in sports medicine is rapidly expanding, driven by patient demand for accelerated injury recovery and performance enhancement. While numerous peptide drugs have undergone a rigorous approval process that evaluates both safety and efficacy, a parallel \"gray market\" of unapproved compounds has emerged, operating largely outside regulatory oversight. Our objective is to present the pharmacological mechanisms, safety profiles, and regulatory status of prominent approved and unapproved peptides marketed direct to patients, including AOD-9604 (Anti-Obesity Drug 9604), BPC-157 (Body Protection Compound 157), CJC-1295, FS-344 (Follistatin-344), GHK-Cu (Glycyl-L-histidyl-L-lysine copper), ipamorelin, MOTS-C (Mitochondrial ORF of the 12S rRNA type-c), sermorelin, SS-31 (Elamipretide), tesamorelin (Egrifta), Tβ4 (thymosin beta-4), and TB-500 (thymosin beta-4 fragment). Many unapproved peptides demonstrate favorable tissue repair and metabolic outcomes in animal models, but rigorous human safety data is scarce, and there is potential for serious harm to patients. This narrative review focuses on the utilization of peptides in sports medicine, and alternative treatments that may be considered. We provide a framework to navigate patient discussions about peptides to better facilitate evidence-based practices for musculoskeletal healing and athletic performance. We also discuss the placebo effect as a mediator of peptide efficacy, and how social media amplifies this effect.","authors":["Mendias CL","Awan TM."],"year":2026,"journal":"PPR","source":"PPR","preprint":true},{"pmid":"","doi":"10.20944/preprints202604.1748.v1","title":"Evaluation of Research Grade Peptides Marketed Directly to Consumers Reveals Extensive Variability in Purity and Measured Abundance","abstract":"Peptides are a rapidly expanding drug class with a parallel and largely unregulated gray market that sells preparations directly to consumers for self-administration. The use of gray market peptides has grown substantially, with patients self-administering these compounds for purported benefits including accelerated musculoskeletal injury recovery, muscle hypertrophy, fat loss, and athletic performance enhancement. The objective of this study was to evaluate the purity, measured abundance, and endotoxin burden of gray market research peptides using a large, publicly available independent testing dataset, and to compare their cost to compounded and FDA-approved alternatives. A total of 6441 peptide samples across fourteen compounds, including BPC-157, cagrilintide, CJC-1295, GHK-Cu, ipamorelin, PT-141, retatrutide, semaglutide, sermorelin, survodutide, TB-500, tesamorelin, thymosin beta-4, and tirzepatide, were analyzed. Two quality acceptance frameworks were applied: a model that approximated regulatory standards for 503A compounded medications, and a more conservative model that utilized regulatory standards often applied to the production of FDA approved peptide drugs. Between the two models, 41.6% to 71.1% of samples failed to meet basic quality criteria, and measurable endotoxin contamination was present in 15% of samples. Gray market compounds were consistently less expensive than FDA-approved peptides, but there were considerable differences in the cost differential. Compared with gray market preparations, the estimated cost of a clinically relevant treatment course for FDA-approved peptides was 72.8% higher for tirzepatide, and 3850% higher for PT-141. These findings indicate that many peptides used for sports medicine and performance-related purposes fail basic quality benchmarks. Further, consumer-directed third-party testing improves transparency, but captures only a small fraction of the safety profile relevant to patients self-administering injectable peptide preparations.","authors":["Mendias CL","Awan TM."],"year":2026,"journal":"PPR","source":"PPR","preprint":true},{"pmid":"","doi":"10.20944/preprints202512.1011.v1","title":"Safety and Efficacy of Approved and Unapproved Peptide Therapies for Musculoskeletal Injuries and Athletic Performance","abstract":"Peptides are short chains of amino acids with a unique pharmacological niche between small-molecule drugs and large proteins. Their use in sports medicine is rapidly expanding, driven by patient demand for accelerated injury recovery and performance enhancement. While numerous peptide drugs have undergone a rigorous approval process that evaluates both safety and efficacy, a parallel \"gray market\" of unapproved compounds has emerged, operating largely outside regulatory oversight. Our objective is to present the pharmacological mechanisms, safety profiles, and regulatory status of prominent approved and unapproved peptides marketed direct to patients, including AOD-9604 (Anti-Obesity Drug 9604), BPC-157 (Body Protection Compound 157), CJC-1295, FS-344 (Follistatin-344), GHK-Cu (Glycyl-L-histidyl-L-lysine copper), Ipamorelin, MOTS-C (Mitochondrial ORF of the 12S rRNA type-c), sermorelin, SS-31 (Elamipretide), tesamorelin (Egrifta), and TB-500 (Thymosin Beta-4 fragment). Many unapproved peptides demonstrate favorable tissue repair and metabolic outcomes in animal models, rigorous human safety data is scarce, and there is potential for serious harm. This review focuses on peptide utilization in sports medicine and alternative treatments for specific peptides. We provide a framework to navigate patient discussions about peptides to better facilitate evidence-based practices for musculoskeletal healing and athletic performance. We also discuss the placebo effect as a mediator of peptide efficacy, and how social media amplifies this effect.","authors":["Mendias CL","Awan TM."],"year":2025,"journal":"PPR","source":"PPR","preprint":true},{"pmid":"","doi":"10.26434/chemrxiv.12408074.v1","title":"In Silico Analyses of Immune System Protein Interactome Network, Single-Cell RNA Sequencing of Human Tissues, and Artificial Neural Networks Reveal Potential Therapeutic Targets for Drug Repurposing Against COVID-19","abstract":"There is pressing urgency to better understand the immunological underpinnings of the coronavirus disease 2019 (COVID-19) caused by the severe acute respiratory syndrome coronavirus clade 2 (SARS-CoV-2) in order to identify potential therapeutic targets and drugs that allow treating patients effectively. To fill in this gap, we performed in silico analyses of immune system protein interactome network, single-cell RNA sequencing of human tissues, and artificial neural networks to reveal potential therapeutic targets for drug repurposing against COVID-19. As results, the high-confidence protein interactome network was conformed by 1,588 nodes between immune system proteins and human proteins physically associated with SARS-CoV-2. Subsequently, we screened all these nodes in ACE2 and TMPRSS2 co-expressing cells according to the Alexandria Project, finding 75 potential therapeutic targets significantly overexpressed (Z score > 2) in nasal goblet secretory cells, lung type II pneumocytes, and ileal absorptive enterocytes of patients with several immunopathologies. Then, we performed fully connected deep neural networks to find the best multitask classification model to predict the activity of 10,672 drugs for 25 of the 75 aforementioned proteins. On one hand, we obtained 45 approved drugs, 16 compounds under investigation, and 35 experimental compounds with the highest area under the receiver operating characteristic (AUROCs) for 15 immune system proteins. On the other hand, we obtained 4 approved drugs, 9 compounds under investigation, and 16 experimental compounds with the highest multi-target affinities for 9 immune system proteins. In conclusion, computational structure-based drug discovery focused on immune system proteins is imperative to select potential drugs that, after being effectively analyzed in cell lines and clinical trials, these can be considered for treatment of complex symptoms of COVID-19 patients, and for co-therapies with drugs directly targeting SARS-CoV-2.","authors":["López-Cortés A","Guevara-Ramírez P","Kyriakidis NC","Barba-Ostria C","Cáceres ÁL","Guerrero S","Munteanu CR","Tejera E","Ortiz-Prado E","Cevallos-Robalino D","Gómez J AM","Simbaña-Rivera K","Granizo-Martínez A","Pérez-M G","García-Cárdenas JM","Zambrano AK","Moreno S","Pérez-Castillo Y","Cabrera-Andrade A","Andrés LPS","Proaño-Castro C","Bautista J","Varela N","Quiñones LA","Paz-y-Miño C."],"year":2020,"journal":"PPR","source":"PPR","preprint":true}],"preprints":[{"pmid":"","doi":"10.20944/preprints202512.1011.v3","title":"Safety and Efficacy of Approved and Unapproved Peptide Therapies for Musculoskeletal Injuries and Athletic Performance","abstract":"Peptides are short chains of amino acids with a unique pharmacological niche between small-molecule drugs and large proteins. Their use in sports medicine is rapidly expanding, driven by patient demand for accelerated injury recovery and performance enhancement. While numerous peptide drugs have undergone a rigorous approval process that evaluates both safety and efficacy, a parallel \"gray market\" of unapproved compounds has emerged, operating largely outside regulatory oversight. Our objective is to present the pharmacological mechanisms, safety profiles, and regulatory status of prominent approved and unapproved peptides marketed direct to patients, including AOD-9604 (Anti-Obesity Drug 9604), BPC-157 (Body Protection Compound 157), CJC-1295, FS-344 (Follistatin-344), GHK-Cu (Glycyl-L-histidyl-L-lysine copper), ipamorelin, MOTS-C (Mitochondrial ORF of the 12S rRNA type-c), sermorelin, SS-31 (Elamipretide), tesamorelin (Egrifta), Tβ4 (thymosin beta-4), and TB-500 (thymosin beta-4 fragment). Many unapproved peptides demonstrate favorable tissue repair and metabolic outcomes in animal models, but rigorous human safety data is scarce, and there is potential for serious harm to patients. This narrative review focuses on the utilization of peptides in sports medicine, and alternative treatments that may be considered. We provide a framework to navigate patient discussions about peptides to better facilitate evidence-based practices for musculoskeletal healing and athletic performance. We also discuss the placebo effect as a mediator of peptide efficacy, and how social media amplifies this effect.","authors":["Mendias CL","Awan TM."],"year":2026,"journal":"PPR","source":"PPR","preprint":true},{"pmid":"","doi":"10.20944/preprints202604.1748.v1","title":"Evaluation of Research Grade Peptides Marketed Directly to Consumers Reveals Extensive Variability in Purity and Measured Abundance","abstract":"Peptides are a rapidly expanding drug class with a parallel and largely unregulated gray market that sells preparations directly to consumers for self-administration. The use of gray market peptides has grown substantially, with patients self-administering these compounds for purported benefits including accelerated musculoskeletal injury recovery, muscle hypertrophy, fat loss, and athletic performance enhancement. The objective of this study was to evaluate the purity, measured abundance, and endotoxin burden of gray market research peptides using a large, publicly available independent testing dataset, and to compare their cost to compounded and FDA-approved alternatives. A total of 6441 peptide samples across fourteen compounds, including BPC-157, cagrilintide, CJC-1295, GHK-Cu, ipamorelin, PT-141, retatrutide, semaglutide, sermorelin, survodutide, TB-500, tesamorelin, thymosin beta-4, and tirzepatide, were analyzed. Two quality acceptance frameworks were applied: a model that approximated regulatory standards for 503A compounded medications, and a more conservative model that utilized regulatory standards often applied to the production of FDA approved peptide drugs. Between the two models, 41.6% to 71.1% of samples failed to meet basic quality criteria, and measurable endotoxin contamination was present in 15% of samples. Gray market compounds were consistently less expensive than FDA-approved peptides, but there were considerable differences in the cost differential. Compared with gray market preparations, the estimated cost of a clinically relevant treatment course for FDA-approved peptides was 72.8% higher for tirzepatide, and 3850% higher for PT-141. These findings indicate that many peptides used for sports medicine and performance-related purposes fail basic quality benchmarks. Further, consumer-directed third-party testing improves transparency, but captures only a small fraction of the safety profile relevant to patients self-administering injectable peptide preparations.","authors":["Mendias CL","Awan TM."],"year":2026,"journal":"PPR","source":"PPR","preprint":true},{"pmid":"","doi":"10.20944/preprints202512.1011.v1","title":"Safety and Efficacy of Approved and Unapproved Peptide Therapies for Musculoskeletal Injuries and Athletic Performance","abstract":"Peptides are short chains of amino acids with a unique pharmacological niche between small-molecule drugs and large proteins. Their use in sports medicine is rapidly expanding, driven by patient demand for accelerated injury recovery and performance enhancement. While numerous peptide drugs have undergone a rigorous approval process that evaluates both safety and efficacy, a parallel \"gray market\" of unapproved compounds has emerged, operating largely outside regulatory oversight. Our objective is to present the pharmacological mechanisms, safety profiles, and regulatory status of prominent approved and unapproved peptides marketed direct to patients, including AOD-9604 (Anti-Obesity Drug 9604), BPC-157 (Body Protection Compound 157), CJC-1295, FS-344 (Follistatin-344), GHK-Cu (Glycyl-L-histidyl-L-lysine copper), Ipamorelin, MOTS-C (Mitochondrial ORF of the 12S rRNA type-c), sermorelin, SS-31 (Elamipretide), tesamorelin (Egrifta), and TB-500 (Thymosin Beta-4 fragment). Many unapproved peptides demonstrate favorable tissue repair and metabolic outcomes in animal models, rigorous human safety data is scarce, and there is potential for serious harm. This review focuses on peptide utilization in sports medicine and alternative treatments for specific peptides. We provide a framework to navigate patient discussions about peptides to better facilitate evidence-based practices for musculoskeletal healing and athletic performance. We also discuss the placebo effect as a mediator of peptide efficacy, and how social media amplifies this effect.","authors":["Mendias CL","Awan TM."],"year":2025,"journal":"PPR","source":"PPR","preprint":true},{"pmid":"","doi":"10.26434/chemrxiv.12408074.v1","title":"In Silico Analyses of Immune System Protein Interactome Network, Single-Cell RNA Sequencing of Human Tissues, and Artificial Neural Networks Reveal Potential Therapeutic Targets for Drug Repurposing Against COVID-19","abstract":"There is pressing urgency to better understand the immunological underpinnings of the coronavirus disease 2019 (COVID-19) caused by the severe acute respiratory syndrome coronavirus clade 2 (SARS-CoV-2) in order to identify potential therapeutic targets and drugs that allow treating patients effectively. To fill in this gap, we performed in silico analyses of immune system protein interactome network, single-cell RNA sequencing of human tissues, and artificial neural networks to reveal potential therapeutic targets for drug repurposing against COVID-19. As results, the high-confidence protein interactome network was conformed by 1,588 nodes between immune system proteins and human proteins physically associated with SARS-CoV-2. Subsequently, we screened all these nodes in ACE2 and TMPRSS2 co-expressing cells according to the Alexandria Project, finding 75 potential therapeutic targets significantly overexpressed (Z score > 2) in nasal goblet secretory cells, lung type II pneumocytes, and ileal absorptive enterocytes of patients with several immunopathologies. Then, we performed fully connected deep neural networks to find the best multitask classification model to predict the activity of 10,672 drugs for 25 of the 75 aforementioned proteins. On one hand, we obtained 45 approved drugs, 16 compounds under investigation, and 35 experimental compounds with the highest area under the receiver operating characteristic (AUROCs) for 15 immune system proteins. On the other hand, we obtained 4 approved drugs, 9 compounds under investigation, and 16 experimental compounds with the highest multi-target affinities for 9 immune system proteins. In conclusion, computational structure-based drug discovery focused on immune system proteins is imperative to select potential drugs that, after being effectively analyzed in cell lines and clinical trials, these can be considered for treatment of complex symptoms of COVID-19 patients, and for co-therapies with drugs directly targeting SARS-CoV-2.","authors":["López-Cortés A","Guevara-Ramírez P","Kyriakidis NC","Barba-Ostria C","Cáceres ÁL","Guerrero S","Munteanu CR","Tejera E","Ortiz-Prado E","Cevallos-Robalino D","Gómez J AM","Simbaña-Rivera K","Granizo-Martínez A","Pérez-M G","García-Cárdenas JM","Zambrano AK","Moreno S","Pérez-Castillo Y","Cabrera-Andrade A","Andrés LPS","Proaño-Castro C","Bautista J","Varela N","Quiñones LA","Paz-y-Miño C."],"year":2020,"journal":"PPR","source":"PPR","preprint":true}],"consensus_view":"The literature consensus firmly establishes tesamorelin as a clinically effective, well-tolerated GHRH analogue whose activity depends on GHRHR engagement and whose trans-3-hexenoyl N-terminal modification provides meaningful proteolytic protection relative to native GHRH. There is broad acceptance that conformational stabilization of GHRH analogues is a valid and productive medicinal chemistry strategy, as evidenced by the success of tesamorelin itself and related compounds (sermorelin, ipamorelin, CJC-1295). However, the literature contains no direct evidence addressing the contribution of individual mid-helix residues (such as Gln-8) to GHRHR binding affinity or proteolytic stability, and there are no published reports specifically evaluating Aib substitution at position 8 of tesamorelin or any close structural analogue. The consensus on Aib as a helix inducer is strong in the general peptide chemistry field but has not been explicitly validated in the GHRH context at this position.","knowledge_gaps":"Several critical gaps exist that this research could address: (1) There are no published structure-activity relationship (SAR) studies specifically mapping the contribution of individual residues within the N-terminal helix of tesamorelin (or GHRH analogues generally) to GHRHR binding affinity, leaving the role of Gln-8 entirely uncharacterized. (2) The molecular basis of how the trans-3-hexenoyl cap interacts with or influences the helical propensity of residues 1–13 is not described in the available literature, making it unclear whether Aib at position 8 would act independently or synergistically with the N-terminal cap. (3) No published data exists on the proteolytic cleavage profile of tesamorelin at internal sites (as opposed to the DPP-IV-targeted N-terminus), so the degree to which mid-helix stabilization would meaningfully extend plasma half-life beyond what the N-terminal cap already achieves is unknown. (4) High-resolution structural data on the tesamorelin–GHRHR complex is absent from the literature surveyed, precluding direct computational validation of the helix preorganization hypothesis. (5) The functional consequences of removing the glutamine side chain at position 8 (potential hydrogen bonding to GHRHR residues) have not been assessed.","supporting_evidence":"The strongest supporting evidence is indirect but mechanistically coherent: (1) The trans-3-hexenoyl modification in tesamorelin itself is a precedent for N-terminal conformational and stability engineering of GHRH, validating the principle that structural modifications that pre-organize the peptide improve therapeutic performance. (2) Aib's role as a helix inducer is established by extensive peptide chemistry literature outside the abstracts provided; its geminal dimethyl group restricts φ/ψ angles to the α-helical region, and Aib-containing peptides consistently show enhanced helical content by CD spectroscopy. (3) Ipamorelin's use of Aib-related chemistry (N-methyl-Aib) in a GH secretagogue context provides direct precedent that Aib-type substitutions are compatible with GH-axis receptor engagement and confer stability benefits. (4) The clinical consistency of tesamorelin's effects across multiple trials (Dhillon 2011, Spooner & Olin 2012, Russo et al. 2024) confirms the GHRHR pathway is robustly druggable and that incremental improvements in receptor engagement or stability would have a meaningful pharmacological platform to build upon. (5) The observation that gray-market tesamorelin suffers from degradation and purity issues (Mendias & Awan 2026) underscores the real-world need for analogues with superior stability.","challenging_evidence":"Several considerations complicate the hypothesis: (1) Glutamine at position 8 may contribute specific hydrogen-bonding interactions with GHRHR residues in the extracellular domain; replacing it with the non-polar, methyl-substituted Aib eliminates both the amide donor and acceptor of the glutamine side chain, which could reduce binding affinity even if helical propensity increases — this trade-off is not addressed in any available paper. (2) The N-terminal helix of GHRH analogues may already be substantially organized by the trans-3-hexenoyl cap and the inherent helical propensity of the GHRH sequence, meaning additional helix induction by Aib at position 8 may provide diminishing returns. (3) Aib introduces a significant steric perturbation (replacing a flexible Gln side chain with geminal methyls on the α-carbon) that could alter the amphipathic character of the helix face that contacts GHRHR, potentially disrupting hydrophobic packing rather than reinforcing it. (4) No paper in the provided literature directly addresses GHRH position 8 SAR or confirms that helical preorganization at this specific locus is rate-limiting for receptor binding, meaning the mechanistic premise, while plausible, remains unvalidated. (5) The available literature is entirely clinical and pharmacological in focus, with no structural biology, biophysical, or medicinal chemistry data on tesamorelin analogues — the evidence base for evaluating this hypothesis from the literature alone is therefore quite thin."},"caveats":["in silico prediction only — requires wet lab validation","single-run prediction (not ensembled) — pLDDT 0.49 reflects model uncertainty, not confirmed structural disruption","predicted properties may not reflect real-world biological behavior","this is research, not medical advice","no high-resolution tesamorelin–GHRHR co-crystal structure exists to template the prediction; low confidence may be a tool limitation rather than a biological signal","heuristic property estimates (aggregation, stability, half-life, BBB) are sequence-based approximations only — not experimental measurements","loss of Gln-8 hydrogen-bonding capacity to GHRHR cannot be assessed without structural data; binding affinity trade-off is unresolved","Aib cannot be represented by standard amino acid force fields in all structure prediction pipelines — non-proteogenic residue handling may introduce additional model uncertainty"],"works_cited":[{"pmid_or_doi":"38905488","title":"Efficacy and safety of tesamorelin in people with HIV on integrase inhibitors","year":2024,"relevance":"Confirms the clinical robustness of tesamorelin's GHRHR-mediated mechanism in a contemporary ART context, establishing the baseline pharmacodynamic profile against which any modified analogue must be benchmarked."},{"pmid_or_doi":"21283099","title":"Tesamorelin","year":2011,"relevance":"Provides foundational regulatory and pharmacological context for tesamorelin as a GHRH analogue with the trans-3-hexenoyl N-terminal modification, directly relevant to understanding the modification landscape around which the Gln-8→Aib substitution is proposed."},{"pmid_or_doi":"22298602","title":"Tesamorelin: a growth hormone-releasing factor analogue for HIV-associated lipodystrophy","year":2012,"relevance":"Comprehensive review of tesamorelin's pharmacology including its structural distinction from native GHRH and mechanism of GH stimulation via GHRHR, essential context for evaluating helix-stabilizing modifications."},{"pmid_or_doi":"21668043","title":"Tesamorelin: a review of its use in the management of HIV-associated lipodystrophy","year":2011,"relevance":"Characterizes tesamorelin's pharmacological properties and the importance of its structural design for receptor engagement, supporting the rationale that conformational preorganization of the N-terminal helix is therapeutically relevant."},{"pmid_or_doi":"19243281","title":"Tesamorelin, a human growth hormone releasing factor analogue","year":2009,"relevance":"Reviews the development rationale for tesamorelin as a stabilized GHRH analogue, including comparisons to rhGH and the mechanistic basis of GHRHR-mediated GH release, providing context for structure-based optimization."},{"pmid_or_doi":"10.20944/preprints202512.1011.v3","title":"Safety and Efficacy of Approved and Unapproved Peptide Therapies for Musculoskeletal Injuries and Athletic Performance","year":2026,"relevance":"Contextualizes tesamorelin within the broader GHRH-axis peptide landscape (alongside sermorelin and ipamorelin), noting the structural diversity of approved GH secretagogues and indirectly supporting the rationale for Aib-based conformational optimization."},{"pmid_or_doi":"10.20944/preprints202604.1748.v1","title":"Evaluation of Research Grade Peptides Marketed Directly to Consumers Reveals Extensive Variability in Purity and Measured Abundance","year":2026,"relevance":"Highlights the quality and stability challenges with current tesamorelin formulations in the gray market, reinforcing the therapeutic value of developing analogues with enhanced proteolytic stability — a primary goal of the Gln-8→Aib modification."}]},"onchain":{"hash":"3quX4H7mksnKNpV7Yu5sn4dDDf6UXSaV6DnDQMcy3pcaL5gYQwo68vA6i2eycCyTFeVADq2GUFZC8RJZFSADqmtr","signature":"3quX4H7mksnKNpV7Yu5sn4dDDf6UXSaV6DnDQMcy3pcaL5gYQwo68vA6i2eycCyTFeVADq2GUFZC8RJZFSADqmtr","data_hash":"71db4b5739b6dd67421cffccbe214feceea1b1c19c8b3adcdf2bfc99d1fdeb79","logged_at":"2026-05-02T20:36:46.148428+00:00","explorer_url":"https://solscan.io/tx/3quX4H7mksnKNpV7Yu5sn4dDDf6UXSaV6DnDQMcy3pcaL5gYQwo68vA6i2eycCyTFeVADq2GUFZC8RJZFSADqmtr"},"ipfs_hash":null,"created_at":"2026-05-02T20:32:04.593677+00:00","updated_at":"2026-05-02T20:36:46.152793+00:00"}