What the human research shows
A genuinely well-evidenced drug for a narrow purpose — and a good example of how a real A-grade outcome in one population gets stretched into claims for everyone else. The visceral-fat effect is solid in HIV lipodystrophy. Nothing on this page supports the way it is marketed on the grey market.
| Outcome | Grade | Effect size | Human studies | Where the evidence comes from |
|---|---|---|---|---|
| Visceral fat (HIV lipodystrophy) | AEstablished | Moderate | 2 phase 3 RCTs (n=816) | Pooled phase 3: visceral adipose tissue −15.2% at 26 weeks vs +5% on placebo; effect lost within 26 weeks of stopping.1 |
| Liver fat (HIV with NAFLD) | BProbable | Moderate | 1 RCT (n=61) | Hepatic fat fraction fell by about a third over 12 months vs placebo; a specific population, one trial.2 |
| Cognition in older adults | CWeak | Small | 1 RCT (n=152) | 20 weeks of tesamorelin improved some executive-function measures in healthy older adults and those with mild cognitive impairment. Single trial, never replicated or developed further.3 |
| Fat loss in healthy adults | DNo human evidence | Not measurable | None | Not studied. The approved population is not a proxy for the general public. |
| IGF-1 elevation and glucose effectsadverse | AEstablished | Small | Phase 3 programme | Raises IGF-1 as intended; small rises in blood glucose and injection-site reactions are documented. Long-term cancer risk at elevated IGF-1 is the reason for the narrow label.1 |
Literature searched to 2 September 2026. Human studies only; animal and cell work informs the mechanism section and nothing else.
What it is
Tesamorelin is the first 44 amino acids of natural growth-hormone-releasing hormone with a chemical cap added to stop it being broken down quickly. Given as a daily injection, it stimulates the pituitary to release growth hormone in a pattern closer to the body's own than injected growth hormone itself.
Theratechnologies won FDA approval in 2010 as Egrifta, for a specific problem — the abdominal fat accumulation seen in some people with HIV on older antiretroviral drugs. It has never been approved for anything else, and the European application was withdrawn.
How it is thought to work
By acting on GHRH receptors in the pituitary it raises pulsatile growth hormone and, downstream, IGF-1. Growth hormone mobilises fat, particularly visceral fat, which is why the trials measured abdominal fat by CT scan rather than body weight — overall weight changes little.
What is still unknown
- Whether any of the fat effect applies to people without HIV lipodystrophy; it has not been tested.
- Long-term safety of sustained IGF-1 elevation; the approval carries warnings about active malignancy and glucose intolerance.
- Whether the single cognition trial would replicate.
Regulatory status
Egrifta, for excess abdominal fat in HIV-associated lipodystrophy only.
The EMA application was withdrawn; no EU marketing authorisation exists.
Not licensed by the MHRA.
Growth-hormone-releasing factors are banned at all times.
Questions people actually ask
Does tesamorelin burn belly fat?
Is tesamorelin the same as growth hormone?
Is tesamorelin legal?
References
- 1Falutz J, et al. Effects of tesamorelin, a growth hormone-releasing factor, in HIV-infected patients with abdominal fat accumulation: pooled analysis of two phase 3 trials.J Acquir Immune Defic Syndr, 2010;53:311–322816 participants; the approval basis.
- 2Stanley TL, et al. Effects of tesamorelin on non-alcoholic fatty liver disease in HIV: a randomised, double-blind, placebo-controlled trial.Lancet HIV, 201961 participants, 12 months.
- 3Baker LD, et al. Effects of growth hormone-releasing hormone on cognitive function in adults with mild cognitive impairment and healthy older adults.Arch Neurol, 2012;69:1420–1429152 adults, 20 weeks; not replicated.
Change log
- 2026-09-02Full page. Added liver-fat, cognition and IGF-1 rows; regional status; FAQ.
- 2026-09-01Initial publication.