# Tesamorelin

> Tesamorelin is a synthetic 44-amino-acid analogue of human growth hormone-releasing hormone (GHRH) carrying an N-terminal trans-3-hexenoyl group. It stimulates release of the body's own growth hormone and is FDA approved for reducing excess abdominal fat in people with HIV-associated lipodystrophy. Published research also covers its effects on liver fat, fat quality, and neurocognition.

Canonical: https://peptideproperties.com/compounds/tesamorelin/

## Identity

- **Class:** Growth Hormone Secretagogues & GHRH Analogs
- **Also known as:** TH9507
- **Molecular formula:** C221H366N72O67S
- **Molecular weight:** 5136 g/mol
- **Monoisotopic mass:** 5134.7234 Da
- **CAS number:** 218949-48-5
- **PubChem CID:** 16137828
- **InChIKey:** QBEPNUQJQWDYKU-BMGKTWPMSA-N
- **Sequence:** YADAIFTNSYRKVLGQLSARKLLQDIMSRQQGESNQERGARARL
- **Sequence notes:** N-terminal (3E)-hex-3-enoyl (trans-3-hexenoyl) group on Tyr1; C-terminal amide on Leu44

## Key facts

- Class: synthetic growth hormone-releasing hormone (GHRH) analogue
- Length: 44 amino acids, matching the full human GHRH(1-44) sequence
- Modifications: N-terminal (3E)-hex-3-enoyl group and C-terminal amide
- Formula C221H366N72O67S; molecular weight 5136 g/mol (PubChem CID 16137828)
- Development code: TH9507
- FDA approved November 2010 for excess abdominal fat in HIV-associated lipodystrophy

## What Is Tesamorelin?

Tesamorelin is a synthetic analogue of human growth hormone-releasing hormone (GHRH) that stimulates the synthesis and release of the body's own growth hormone. In the United States it is approved for reducing excess abdominal fat in people with HIV-associated lipodystrophy, and a 2011 review described it as the first and only treatment indicated for that purpose.[1][2]Rather than supplying growth hormone directly, tesamorelin acts upstream of it. The peptide mimics the hypothalamic signal that prompts growth hormone release, so its downstream effects, including increases in insulin-like growth factor 1 (IGF-1), depend on the body's own endocrine response.[2][3]Most published human research on tesamorelin comes from clinical trials in people living with HIV. Those studies measured visceral adipose tissue, waist circumference, liver fat, fat quality and, more recently, neurocognitive performance. Outside that population, reviews describe the evidence for other uses as limited.[4][5]

## Chemical Structure and Molecular Identity

Tesamorelin is a 44-amino-acid peptide built on the full human GHRH(1-44) sequence, with a (3E)-hex-3-enoyl group attached to the N-terminal tyrosine and an amide at the C-terminal leucine. PubChem lists it under CID 16137828 with the molecular formula C221H366N72O67S and a molecular weight of 5136 g/mol.The backbone is identical to native human GHRH, sometimes called somatoliberin. The only structural change is the trans-3-hexenoyl cap on the N-terminus, reflected in the systematic synonym (3E)-hex-3-enoylsomatoliberin. The peptide contains a single sulfur atom, contributed by the methionine at position 27.
### Key identifiers

- InChIKey: QBEPNUQJQWDYKU-BMGKTWPMSA-N
- CAS numbers listed in PubChem: 218949-48-5 and 804475-66-9
- Development code: TH9507
- ATC code: H01AC06At roughly 5.1 kDa with many charged arginine, lysine, aspartate and glutamate side chains, tesamorelin is highly polar. PubChem's computed XLogP of -23.3 and topological polar surface area of 2360 reflect a large, water-soluble molecule typical of full-length peptide hormones.

## Research History and Development

Tesamorelin was developed as a GHRH analogue in response to the adverse effects seen with recombinant human growth hormone therapy, with the aim of raising growth hormone through the body's own regulatory pathway. It was investigated under the code TH9507 for several conditions associated with relative growth hormone deficiency.[5][4]By 2009, a multicenter, randomized, placebo-controlled phase 3 trial had suggested a benefit on visceral fat in HIV-related lipodystrophy with a good safety profile. The same review judged other potential indications less promising on the data then available.[5]Two 26-week phase 3 trials in patients with HIV-associated central fat accumulation, each followed by an extension phase to week 52, formed the core of the clinical evidence.[2][4] In November 2010, the US Food and Drug Administration approved tesamorelin for the reduction of excess abdominal fat in HIV-infected patients with lipodystrophy.[1]Since approval, investigators have reused data and samples from these and newer randomized trials to study liver fat, adipose tissue quality, hepatic gene expression, neurocognition, and outcomes in people taking current antiretroviral regimens.[6][7][8][3]

## Mechanisms Studied in Research

The primary mechanism studied for tesamorelin is stimulation of endogenous growth hormone secretion, which in turn raises circulating IGF-1. Because it works through the native GHRH pathway, investigators have used tesamorelin trials to study the biology of pulsatile growth hormone action.[2][7][3]
### Adipose tissue
In phase 3 trials, tesamorelin reduced visceral adipose tissue without a clinically significant effect on subcutaneous fat, a pattern that separates its effects on visceral and subcutaneous depots.[2] A later CT-based analysis found that fat density, a marker of adipocyte quality, rose in both visceral and subcutaneous depots independent of the change in fat quantity.[6]
### Liver gene expression
Paired liver biopsies from a randomized trial in HIV-associated nonalcoholic fatty liver disease (NAFLD) showed that tesamorelin increased hepatic expression of gene sets involved in oxidative phosphorylation and decreased gene sets tied to inflammation, tissue repair and cell division. These shifts correlated with an improved fibrosis-related gene score.[7]
### Musculoskeletal signaling
Narrative reviews group tesamorelin with other growth hormone secretagogues proposed to act through IGF-1 signaling and satellite cell repair. The same reviews note that clinical trials for orthopedic applications are lacking.[9][10]

## Key Findings From Published Studies

The strongest human evidence shows that tesamorelin reduces visceral fat and waist circumference in people with HIV-associated central fat accumulation, with effects that persist only while treatment continues. Newer trials extend these findings to liver fat and fat quality, while results on cognition were not significant.
### Visceral fat in HIV-associated lipodystrophy
In two 26-week phase 3 trials and their pooled analyses, tesamorelin significantly decreased visceral adipose tissue and waist circumference and improved some body image measures, such as belly image distress.[2][4] Visceral fat reductions were maintained through week 52 in participants who continued treatment, but visceral fat reaccumulated after discontinuation.[2] The extension phases did not show an adverse effect on blood glucose or lipid parameters.[4]
### Fat quality
In a pooled analysis of two placebo-controlled trials (193 tesamorelin responders, 148 placebo), mean visceral fat density increased by 6.2 Hounsfield units with tesamorelin versus 0.3 with placebo over 26 weeks, and subcutaneous fat density rose by 4.0 versus 0.3 units.[6]
### Liver fat and current antiretroviral therapy
The authors of a randomized placebo-controlled trial in HIV-associated NAFLD report that tesamorelin reduced liver fat and prevented fibrosis progression over one year.[7] A sub-analysis of 38 participants on integrase inhibitor-based regimens found significant 12-month declines in visceral fat (median -25 versus +14 cm2), hepatic fat fraction (-4.2% versus -0.5%) and trunk-to-appendicular fat ratio, with a similar frequency of adverse events, including hyperglycemia, between arms.[8]
### Neurocognition
In a 6-month phase 2 open-label trial of 73 virally suppressed adults with HIV and abdominal obesity, tesamorelin reduced waist circumference more than standard of care (median difference -2.7 cm), and IGF-1 rose. The between-group difference in neurocognitive performance was not significant.[3]
### Safety observations
Across 26 weeks of phase 3 therapy, treatment-emergent serious adverse events occurred in fewer than 4% of patients. Most reported events were injection-site reactions or effects associated with growth hormone, such as arthralgia, headache and peripheral edema.[2]As a 44-residue modified peptide, tesamorelin is typically verified with HPLC purity and mass spectrometry identity data on a certificate of analysis.

## Regulatory and Research Status

Tesamorelin is an FDA-approved prescription drug in the United States, indicated for reducing excess abdominal fat in HIV-infected patients with lipodystrophy; it received approval in November 2010.[1] It has been described as the only FDA-approved therapy for abdominal fat accumulation in people with HIV.[8]Its approval does not extend to other uses. Reviews conclude that limited data support off-label applications, and an orthopedic review found no supporting orthopedic evidence for tesamorelin.[4][10] A 2026 sports medicine review discusses tesamorelin alongside both approved and unapproved peptides marketed directly to patients, noting that rigorous human safety data are scarce for many compounds in this space.[11]Published reviews also identify open questions for the approved indication itself, including the need for longer-term safety and adherence data.[2][4] Ongoing research continues to examine liver, metabolic and neurocognitive outcomes in people with HIV.[7][3]Phase 3 trials were completed before integrase inhibitors became a mainstay of HIV treatment, which is why investigators have since analyzed tesamorelin separately in participants on integrase inhibitor-based regimens.[8]

## FAQ

**Is tesamorelin FDA approved?**
Yes. The US Food and Drug Administration approved tesamorelin in November 2010 for the reduction of excess abdominal fat in HIV-infected patients with lipodystrophy. That approval covers only this indication. Reviews describe evidence for other uses as limited, and orthopedic reviews report no supporting clinical evidence for musculoskeletal applications.

**What is the molecular weight of tesamorelin?**
PubChem lists tesamorelin (CID 16137828) with a molecular weight of 5136 g/mol and the molecular formula C221H366N72O67S. The peptide has 44 amino acids, matching the full human GHRH(1-44) sequence, plus an N-terminal (3E)-hex-3-enoyl group and a C-terminal amide. Its InChIKey is QBEPNUQJQWDYKU-BMGKTWPMSA-N.

**Is tesamorelin the same as sermorelin?**
No. Both are analogues of growth hormone-releasing hormone, but sermorelin corresponds to the first 29 residues of GHRH, while tesamorelin keeps all 44 residues of the human sequence and adds a trans-3-hexenoyl group to the N-terminus. Tesamorelin is the compound approved by the FDA for HIV-associated abdominal fat.

**How is tesamorelin different from growth hormone?**
Tesamorelin is not growth hormone. It is a GHRH analogue that stimulates the body's own synthesis and release of growth hormone, which then raises IGF-1. It was developed partly because recombinant human growth hormone therapy carries a range of adverse effects, and researchers hoped a releasing-factor approach would be better tolerated.

**What is TH9507?**
TH9507 is the development code under which tesamorelin was studied before approval. Literature searches and early reviews use TH9507 and tesamorelin interchangeably. The compound is also indexed under the CAS numbers 218949-48-5 and 804475-66-9 and carries the ATC code H01AC06.

**What does the research on tesamorelin show?**
In phase 3 trials in people with HIV-associated central fat accumulation, tesamorelin reduced visceral fat and waist circumference, with fat returning after discontinuation. Later trials reported reduced liver fat, higher fat density on CT, and favorable hepatic gene expression changes. A phase 2 trial found no significant cognitive benefit versus standard of care.

**Has tesamorelin been studied for injury recovery?**
Not in clinical trials. Narrative reviews in orthopedic and sports medicine journals group tesamorelin with other growth hormone secretagogues that may act through IGF-1 signaling, but one review states that tesamorelin has no supporting orthopedic evidence. Its human research base is concentrated in people living with HIV.

## References

1. Grunfeld C, Dritselis A, Kirkpatrick P. Tesamorelin. Nature reviews. Drug discovery 2011. PMID: 21283099
2. Dhillon S. Tesamorelin: a review of its use in the management of HIV-associated lipodystrophy. Drugs 2011. PMID: 21668043
3. Ellis RJ, Vaida F, Hu K, et al. Effects of Tesamorelin on Neurocognitive Impairment in Persons With HIV and Abdominal Obesity. The Journal of infectious diseases 2025. PMID: 39813152
4. Spooner LM, Olin JL. Tesamorelin: a growth hormone-releasing factor analogue for HIV-associated lipodystrophy. The Annals of pharmacotherapy 2012. PMID: 22298602
5. Wang Y, Tomlinson B. Tesamorelin, a human growth hormone releasing factor analogue. Expert opinion on investigational drugs 2009. PMID: 19243281
6. Lake JE, La K, Erlandson KM, et al. Tesamorelin improves fat quality independent of changes in fat quantity. AIDS (London, England) 2021. PMID: 33756511
7. Fourman LT, Billingsley JM, Agyapong G, et al. Effects of tesamorelin on hepatic transcriptomic signatures in HIV-associated NAFLD. JCI insight 2020. PMID: 32701508
8. Russo SC, Ockene MW, Arpante AK, et al. Efficacy and safety of tesamorelin in people with HIV on integrase inhibitors. AIDS (London, England) 2024. PMID: 38905488
9. Rahman OF, Lee SJ, Seeds WA. Therapeutic Peptides in Orthopaedics: Applications, Challenges, and Future Directions. Journal of the American Academy of Orthopaedic Surgeons. Global research & reviews 2026. PMID: 41490200
10. Mayfield CK, Bolia IK, Feingold CL, et al. Injectable Peptide Therapy: A Primer for Orthopaedic and Sports Medicine Physicians. The American journal of sports medicine 2026. PMID: 41476424
11. Mendias CL, Awan TM. Safety and Efficacy of Approved and Unapproved Peptide Therapies for Musculoskeletal Injuries and Athletic Performance. Sports medicine (Auckland, N.Z.) 2026. PMID: 41966639