Tesamorelin: the basics
What is it?
A prescription peptide that increases the body’s release of growth hormone.
Research paper ↗What do people claim it helps with?
Reducing deep abdominal fat in people with HIV-related lipodystrophy is an approved use. General weight loss, bodybuilding and anti-aging claims go beyond that use.
What has research actually shown?
Controlled studies in people with HIV and excess abdominal fat found less visceral fat, the fat around internal organs. This is not the same as a general weight-loss treatment.
Research paper ↗Has this been demonstrated in people?
Demonstrated in people, including controlled clinical trials for the uses described here. Evidence for one diagnosis does not establish benefit for every other claim.
Research paper ↗What side effects, risks and unknowns should I understand?
Injection reactions, joint pain and fluid retention can occur. Blood sugar and IGF-1 can rise. Active cancer and pregnancy are important contraindications.
Prescribing information ↗Is it an approved medicine?
Yes. FDA-approved tesamorelin products treat excess abdominal fat in adults with HIV-associated lipodystrophy; they are not approved for general weight-loss management.
Prescribing information ↗Approval here means U.S. FDA approval and applies to a particular product, formulation and use. This is a starting overview, not a complete side-effect list. Sources checked 10 October 2026; independent scientific review pending.
How is it used or studied?
Prescription injection, with formulation-specific instructions and clinical monitoring.
Different routes and formulations can have different effects. A study of one product does not validate every product with the same peptide name.
A common misunderstanding
Visceral-fat reduction does not necessarily mean substantial weight loss on the scale.
What should I ask a clinician?
- What diagnosis or goal are we trying to address, and what established options are available?
- Was the expected benefit shown in people like me, using this exact product?
- How could my medicines, health conditions or pregnancy plans affect the risks?
- What monitoring is needed, and what would tell us the treatment is helping or should be stopped?
What do the research words mean?
- Peptide
- A short chain of amino acids, the building blocks of proteins.
- Preclinical
- Research in cells, tissues or animals before dependable treatment evidence in people.
- Controlled trial
- A study comparing a treatment with another treatment or a placebo to help separate its effects from other explanations.
- Biomarker
- A measurement, such as a hormone level. A change does not necessarily mean someone feels better or lives longer.
Tesamorelin Evidence & Clinical Profile
Established Clinical Trials
Tesamorelin has been investigated in clinical contexts. Patient outcomes must be evaluated against study size, design, and control cohorts.
Laboratory & In Vivo Assays
Cellular and animal disease models examine receptor binding affinities and signaling cascades, which require human confirmation.
What is Tesamorelin?
Tesamorelin Acetate (Egrifta) is An FDA-approved stabilized analogue of human growth hormone-releasing hormone (GHRH). Approved under the brand name Egrifta for reducing excess visceral abdominal fat in HIV-associated lipodystrophy, supported by multicenter Phase 3 randomized trials. Aliases include: Egrifta, Egrifta SV, TH9507, trans-3-hexenoyl-GHRH.
- Sequence (one-letter)
- Hexenoyl-YADAIFTNSYRKVLGQLSARKLLQDIMSR-NH2
- Molecular formula
- C221H366N72O67S
- Molecular weight
- 5135.8 g/mol
- CAS Number
- 218949-48-5
- UNII Code
- MQG94M5EEO
- PubChem CID
- 16137828
Identifiers are for the free base. The approved medicine contains tesamorelin acetate (UNII LGW5H38VE3).
Identifiers checked against PubChem and FDA's Global Substance Registration System on 13 October 2026. FDA substance record ↗ · PubChem record ↗ See all names and codes in the peptide name index.
Clinical Trials & Human Cohorts
Human research can examine tolerability, symptoms or patient outcomes. The design and comparator determine what each result can establish.
Effects of Tesamorelin on Visceral Abdominal Fat in HIV-Infected Patients [5]
What was reported
Visceral adipose tissue fell with a 15.4% treatment effect vs placebo at 26 weeks, with no significant change in abdominal subcutaneous fat; reductions were maintained to 52 weeks in patients who continued treatment.
What limits the conclusion
Endpoints were imaging and laboratory measures over 26-52 weeks rather than clinical events.
Tesamorelin for Non-Alcoholic Fatty Liver Disease in HIV [2]
What was reported
Hepatic fat fraction fell more with tesamorelin than placebo (absolute -4.1%, relative -37%) over 12 months; 35% vs 4% reached a hepatic fat fraction below 5%.
What limits the conclusion
Small two-site trial; the authors note further studies are needed on long-term effects on liver histology.
How the compound may work
Mechanisms describe how Tesamorelin may affect biological processes. Laboratory findings and patient outcomes answer different questions.
Somatotroph GHRH-R Stimulation
As a growth hormone-releasing factor analogue, it stimulates growth hormone release; IGF-I rose 81% with tesamorelin vs a 5% fall with placebo. [1]
Visceral-Selective Fat Reduction
Visceral fat decreased while abdominal subcutaneous fat did not change significantly. [5]
Areas Being Studied
These research topics reflect active areas of scientific exploration, distinct from unverified commercial marketing claims.
Compare the study designs.
| Study | Design / sample | Outcome type | Key limitation |
|---|---|---|---|
| Phase 3 Pooled Analysis · 2010 [5] | Pooled analysis of two Phase 3 multicenter double-blind RCTs n = 806 |
Clinical endpoint evaluation | Endpoints were imaging and laboratory measures over 26-52 weeks rather than clinical events. |
| NAFLD / MASH Pilot · 2019 [2] | Randomized double-blind placebo-controlled trial n = 61 |
Clinical endpoint evaluation | Small two-site trial; the authors note further studies are needed on long-term effects on liver histology. |
Regulatory Status & Clinical Safety
Regulatory Classification
FDA approved (BLA 022505). WADA Category S2 prohibited substance.
Safety Realities & Impurities
Safety depends on the molecule, formulation, route and evidence. A laboratory purity measurement alone cannot establish safety for human use.
Clinical Trials Registry Records
Official registry records from ClinicalTrials.gov. Study registration does not imply government endorsement or guaranteed efficacy.
TH9507 in Patients With HIV-Associated Lipodystrophy [3]
- Planned enrollment
- 412 (patients)
- Posted results
- Pending in registry
- Sponsor
- Theratechnologies
- Last updated
- 2013
WADA & Anti-Doping Regulations
WADA Section S2: Prohibited Substance
The World Anti-Doping Agency (WADA) classifies Tesamorelin under Section S2 of the Prohibited List. Prohibited at all times (in- and out-of-competition). Last verified: October 2026.
Research Timeline
What Researchers Still Don't Know
Long-term safety profiles
Multi-year observational data in broader heterogeneous cohorts remains uncharacterized.
Optimal dose-response thresholds
Comparative trials optimizing minimal effective exposure versus adverse event rates.
Formulation bioavailability
Differences between oral, subcutaneous, and modified peptide delivery vehicles.
References
Primary sources verified against PubMed / NLM and regulatory databases.
-
Landmark Phase 3 RCT
Metabolic effects of a growth hormone-releasing factor in patients with HIV ↗ (external website)
- Clinical RCT
-
Registry Record
TH9507 in Patients With HIV-Associated Lipodystrophy ↗ (external website)
-
FDA Drug Label
Egrifta (Tesamorelin for Injection) Prescribing Information ↗ (external website)
- Pooled Phase 3 Analysis