Last updated 2 October 2026 · SARMs Store editorial team. Products on this site are supplied strictly for laboratory research and are not for human consumption. This guide summarises published research; it is not medical advice and contains no instructions for use. 18+ only.
Tesamorelin at a glance
| Class | Synthetic analogue of growth hormone releasing hormone (GHRH 1-44) with an N-terminal trans-3-hexenoyl group |
|---|---|
| Developed by | Theratechnologies, Canada, as TH9507 |
| Highest evidence | Two phase III randomised trials; US FDA approval 2010 for one indication |
| Studied for | GHRH receptor signalling, pulsatile growth hormone release, visceral adipose tissue and liver fat in defined patient groups |
| CAS number | 218949-48-5 |
| Format | Lyophilised powder in a sealed vial |
| UK status 2026 | Research chemical; no UK or EU licence; prohibited in sport under WADA S2 |
What tesamorelin is
Growth hormone releasing hormone is the hypothalamic signal that tells the pituitary to release growth hormone. The native 44 amino acid peptide lasts only minutes in the blood because the enzyme DPP-4 cuts it at the second residue. Tesamorelin keeps the full native sequence and attaches a trans-3-hexenoyl group to the first amino acid, which blocks that cut and extends its activity. It binds the same pituitary receptor as GHRH, so it raises the body's own pulsatile growth hormone and, downstream, IGF-1, rather than supplying growth hormone directly. That preserved pulsatility, and the feedback control that comes with it, is the main reason researchers distinguish GHRH analogues from growth hormone itself.
What the research found
Phase III trials. Falutz and colleagues reported in the New England Journal of Medicine in 2007 on 412 people with HIV associated abdominal fat accumulation randomised to tesamorelin or placebo for 26 weeks. Visceral adipose tissue measured by CT fell in the tesamorelin group and rose slightly with placebo, while subcutaneous fat was largely unchanged. A second phase III trial reported similar results, and the pooled data supported US approval in 2010 for that single indication.
Durability. Extension data showed that the visceral fat reduction was largely lost once treatment stopped, which is consistent with a compound that works through ongoing receptor stimulation rather than a lasting change.
Liver fat. Stanley and colleagues reported in JAMA in 2014 a reduction in liver fat over six months in the same patient population, and a larger randomised trial in Lancet HIV in 2019 examined non alcoholic fatty liver disease in people with HIV, reporting less liver fat and less progression of fibrosis than placebo.
Other work. Smaller studies have looked at cognition in older adults and at body composition in other groups, but none has reached the scale of the HIV trials.
What is missing. Any trial outside defined clinical populations, any UK or EU licence, and long term data beyond the trial extensions. Reported adverse effects in the trials included injection site reactions, joint pain and raised blood glucose, and IGF-1 was monitored throughout.
Stability, storage and handling
Lyophilised tesamorelin is stable in transit at ambient temperature. Sealed vials should be refrigerated at 2 to 8C and protected from light, or kept at -20C for longer storage. The certificate should show HPLC purity, mass spectrometry identity matching a molecular weight of about 5,136 g/mol, and the milligram content per vial.
Legal status in the UK, 2026
Not a controlled substance under the Misuse of Drugs Act 1971. Tesamorelin has no UK marketing authorisation, so it cannot be sold or advertised for human use in the UK, where the MHRA would treat it as an unlicensed medicine. It is supplied strictly for laboratory research. Growth hormone releasing hormone analogues, with tesamorelin named, are prohibited at all times under section S2 of the WADA Prohibited List.
What to check before buying
Milligram content per vial, HPLC purity, mass spectrometry identity and a batch number that matches the certificate. Every Origin Peptides batch is independently tested and its certificate of analysis is published on the product page and the Lab Testing page.
Frequently asked questions
Is tesamorelin the same as TH9507?
Yes. TH9507 was the development code used by Theratechnologies; tesamorelin is the generic name.
Is tesamorelin licensed in the UK?
No. It has a US licence for one indication in people with HIV associated abdominal fat accumulation; it has no UK or EU marketing authorisation.
How is tesamorelin different from sermorelin?
Sermorelin is the first 29 amino acids of GHRH with no stabilising change and is cleared quickly. Tesamorelin keeps all 44 amino acids and adds a hexenoyl group that protects it from enzymatic breakdown.
Does tesamorelin contain growth hormone?
No. It acts on the pituitary GHRH receptor and increases the release of the body's own growth hormone; it is not growth hormone.
Is tesamorelin legal in the UK?
Legal to buy and possess as a research compound; not lawful to sell or advertise for human use. It is prohibited at all times in sport under WADA section S2.
Key references
Falutz J, Allas S, Blot K, et al. Metabolic effects of a growth hormone releasing factor in patients with HIV. New England Journal of Medicine. 2007;357(23):2359-2370. Stanley TL, Feldpausch MN, Oh J, et al. Effect of tesamorelin on visceral fat and liver fat in HIV infected patients with abdominal fat accumulation: a randomized clinical trial. JAMA. 2014;312(4):380-389. Stanley TL, Fourman LT, Feldpausch MN, et al. Effects of tesamorelin on non alcoholic fatty liver disease in HIV: a randomised, double blind, multicentre trial. Lancet HIV. 2019;6(12):e821-e830.
Related guides
- Sermorelin research guide
- CJC-1295 and Ipamorelin research guide
- HGH Fragment 176-191 research guide
- How to read a certificate of analysis
Research products: Origin Peptides Tesamorelin 10mg · Full Origin Peptides range · Lab Testing