Tesamorelin
A synthetic GHRH analogue, studied on the growth hormone / IGF-1 axis and clinically documented in a specific population: reduction of visceral fat in patients living with HIV.
What if, instead of supplying growth hormone, one simply stimulated its natural production? That is the approach of Tesamorelin, a GHRH analogue studied on visceral fat.
- Research Use Only
- Molecule under study
- Living document
- Current research state
- EGRIFTA WR is a prescription medicine indicated in the United States to reduce excess abdominal fat in certain adults living with HIV who have lipodystrophy; it is not a general weight-loss indication. The European application was withdrawn in 2012 during assessment. The PHL product remains for research use only.
- Current clinical phase
- Phase 3 completed for the HIV indication; other avenues under research
- Last update
- 25 septembre 2026 · Fiche v1.1
- Living document
- Updated regularly as research progresses.
What is Tesamorelin?
Tesamorelin is a synthetic version of GHRH (Growth Hormone-Releasing Hormone), a 44-amino-acid hormone produced by the hypothalamus.
A trans-3-hexenoyl group is added to its N-terminus. This modification makes it more stable against the enzymes that rapidly degrade natural GHRH.
It was developed under the code TH9507, then evaluated in clinical trials in patients living with HIV with abdominal fat accumulation.
Names you may come across
Tesamorelin appears under its international name, its French form or its development code.
International non-proprietary name, used in the scientific literature.
French form of the international name.
Development code used in early clinical trials.
Understanding it simply
Three simple markers to understand Tesamorelin.
A command signal
Tesamorelin mimics a natural signal sent by the brain to the pituitary gland. This prompts the body to release more of its own growth hormone, which then increases IGF-1 among other effects.
A target: visceral fat
Visceral fat surrounds the abdominal organs. It is the main endpoint measured in its clinical trials.
A specific population
Clinical results concern HIV patients with lipodystrophy, not the general population.
What research shows today
Science advances step by step. We clearly distinguish what is firmly established from what remains under study.
- Tesamorelin is an analogue of human GHRH (44 amino acids) modified at its N-terminus. — établi
- It stimulates pulsatile growth hormone secretion by the pituitary and raises IGF-1. — établi
- Phase 3 trials show a reduction in visceral fat in HIV patients with abdominal accumulation. — établi
- The effect on visceral fat tends to disappear after discontinuation. — établi
- Transposition to other populations and long-term effects: not established. — en cours
Published randomised phase 3 clinical trials, but in a specific population (HIV with abdominal fat accumulation). Outside this setting, data remain limited.
Level of evidence, step by step
- Biochemical mechanism4/4
Action on the GHRH receptor and the GH / IGF-1 axis well described.
- Animal (in vivo)3/4
Preclinical data that supported clinical development.
- Human — HIV population4/4
Published randomised phase 3 trials.
- Human — other populations1/4
Limited data; no established extension of indication.
What the research shows
- In one randomised phase 3 trial, visceral fat decreased by about 10.9% at six months in the studied HIV population; other analyses and extensions observed larger reductions among participants who continued treatment.
- Documented rise in IGF-1 under treatment, consistent with the mechanism on the GH axis.
- Reduction in liver fat observed in HIV patients (Stanley et al., 2014 and 2019).
What still remains to be studied
- Relevance of results outside the HIV population studied: not established.
- Effects on blood glucose: variations monitored in trials; the long-term profile remains to be clarified.
- Lasting cardiovascular or clinical benefit: not demonstrated.
What science shows
Laboratory / cells
- Laboratory studies have helped explain how Tesamorelin binds to the GHRH receptor and triggers the signal for growth hormone release.
Animals
- Animal studies supported the molecule’s development, but cannot by themselves predict its effects in humans.
Humans
- The strongest evidence comes from trials in adults living with HIV who had excess abdominal fat related to lipodystrophy.
- These results do not prove the same effect in a person without HIV who simply wants to change body composition.
Clinical trials
- The major human trials mainly included adults living with HIV who had excessive abdominal fat accumulation related to lipodystrophy.
- In one randomised phase 3 trial, visceral fat decreased by about 10.9% at six months in the studied population. Extension work observed larger reductions among participants who continued treatment.
- The effect on visceral fat can diminish after treatment stops. These figures do not mean that Tesamorelin causes everyone to lose the same percentage of fat.
What we know today
Not all information carries the same weight of evidence. We therefore present it across three clearly distinct levels, from the most solid to the most indicative.
What scientific publications show
Scientific evidence- Trials converge on a measurable reduction in visceral fat in the population studied.
- Effects on total weight and subcutaneous fat are small.
- Authors note the regression of the effect after discontinuation.
What some professionals report
Documented- Its documented clinical use falls under supervised prescription, for a specific indication.
- Clinicians notably monitor IGF-1 and blood glucose in this setting.
What the community reports
Field observations- Off-label uses are discussed online; they are not covered by published trials.
- No individual observation replaces controlled clinical data.
Solid clinical data exist, but for a specific population: they do not automatically generalise.
What does the medical community say?
- Clinical effectiveness on visceral fat has been demonstrated in a clearly defined medical population: certain adults living with HIV who have lipodystrophy.
- EGRIFTA WR (tesamorelin) is a prescription medicine indicated in the United States to reduce excess abdominal fat in these patients. It is not indicated for general weight-loss management.
- Egrifta did not obtain centralised marketing authorisation in the European Union. The European application was withdrawn in 2012 during its assessment.
- The increase in GH and IGF-1 calls for careful medical monitoring. Long-term cardiovascular safety has not been fully established in the US indication.
- The PHL product is distinct from an authorised commercial medicine and remains for research use only.
Why biohacking is interested
- Biohacking communities are mainly interested in it for abdominal or visceral fat, body composition, a leaner appearance, recovery, sleep and the subjective preservation of muscle mass during weight loss.
- These uses outside the studied population do not have the same level of clinical evidence.
What people report online
Positive experiences mentioned
- A waist or abdomen that appears slimmer, sometimes without a large change in weight.
- Better recovery or sleep according to some accounts.
- A feeling of better preserving one’s physique during a calorie deficit.
Other experiences reported
- Little or no change for some users.
- Fatigue, pain or stiffness, tingling or numbness in the hands or arms have been reported.
- Water retention or other subjective effects are mentioned in some reports.
Internet experiences can neither determine true effectiveness nor establish that reported adverse effects were caused by the molecule.
What we know today
- Tesamorelin mimics the natural GHRH signal and increases growth hormone release followed by IGF-1.
- Randomised trials showed a reduction in visceral fat in an HIV population with lipodystrophy.
- The effect may diminish after stopping, and the US indication is not a general weight-loss indication.
What we do not know yet
- The size of any benefit in people without HIV who seek a change in body composition.
- Long-term cardiovascular safety and very long-term clinical benefits.
- The true contribution to effects attributed online to recovery, sleep or muscle preservation.
How does Tesamorelin work?
Tesamorelin acts at the top of the somatotropic axis, along a well-described chain.
Binding to receptors on pituitary somatotroph cells.
Pulsatile GH release, preserving physiological regulation.
Increased hepatic IGF-1 production, mediator of many GH effects.
Increased lipolysis observed, mainly in visceral fat.
The mechanism is established; the size of the effects depends on the population and has only been measured clinically in specific settings.
Timeline des essais cliniques
A molecule under study progresses step by step. Here, simply, is where the research currently stands.
- Research· 1990sCompleted
Development of TH9507
Design of a stabilised GHRH analogue.
- Phase 3· 2007Completed
First phase 3 trial published
Falutz et al. (NEJM): reduction in visceral fat in HIV patients.
- Authorisation· 2010Completed
Authorisation in the United States
Authorisation limited to excess abdominal fat related to lipodystrophy in HIV patients.
- Research· 2014Completed
Visceral and liver fat
Stanley et al. (JAMA) assess the effect on liver fat.
- Ongoing· ActuellementOngoing
Other research settings
Targeted work outside the authorised indication; no established extension of indication.
Les analyses disponibles
The theory is put to the test. Here are the independent analyses already published for Tesamorelin, available in the Analyses Library.
Ouvrir la bibliothèque des analysesQuestions fréquentes
Is Tesamorelin a medicine?
A medicine containing Tesamorelin is authorised in the United States for a specific indication in HIV patients. The product presented by PHL is for research only and is not a medicine.
Is it growth hormone?
Established: no. It is a GHRH analogue that stimulates growth hormone release by the pituitary.
Do the visceral fat results apply to everyone?
To be studied: the trials concern HIV patients with lipodystrophy. Their transposition to other populations has not been demonstrated.
Is it indicated for weight loss?
No. The US indication concerns reducing excess abdominal fat in certain adults living with HIV who have lipodystrophy. It is not a general weight-loss indication.
What adverse effects have been reported?
Established, in published trials: injection-site reactions, joint pain, oedema and blood glucose changes, among others. This profile was described in the population studied.
Does the effect persist after stopping?
Established: in trials, visceral fat largely returned towards its baseline level after discontinuation.
Publications scientifiques
Selection of reference publications on Tesamorelin — phase 3 trials, visceral and liver fat. Evolving bibliography.
Effects of tesamorelin (TH9507), a growth hormone-releasing factor analog, in human immunodeficiency virus-infected patients with excess abdominal fat: a pooled analysis of two multicenter, double-blind placebo-controlled phase 3 trials with safety extension data
Falutz J. et al. · Journal of Clinical Endocrinology & Metabolism · 2010
Effects of tesamorelin on non-alcoholic fatty liver disease in HIV: a randomised, double-blind, multicentre trial
Stanley T. L. et al. · The Lancet HIV · 2019
Glossaire
- GHRH
- Hypothalamic hormone that drives growth hormone release.
- IGF-1
- Growth factor produced mainly by the liver under the effect of growth hormone.
- Visceral fat
- Adipose tissue located around the abdominal organs, distinct from subcutaneous fat.
- Lipodystrophy
- Abnormal distribution of body fat.
- Pituitary gland
- Gland at the base of the brain that secretes, among others, growth hormone.
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Fiche de référence — version 1.1, mise à jour le 25 septembre 2026. The complete regulatory and scientific framework is gathered in the « Information importante » en tête de fiche.