Tesamorelin
Stabilized GHRH(1–44) analogue · Research-grade reference material
Identity
- Molecular formula
- C221H366N72O67S
- Molecular weight
- 5135.87 g/mol
- CAS number
- 218949-48-5
Research Background
Tesamorelin is a synthetic analog of the full 44-amino-acid human growth hormone-releasing hormone, distinguished by a lipophilic hexenoyl modification on the N-terminal tyrosine, engineered to resist the enzymatic degradation (DPP-IV) that rapidly breaks down native GHRH.
Tesamorelin is FDA-approved under the brand name Egrifta SV for a specific, narrow indication: reducing excess visceral adipose tissue in patients with HIV-associated lipodystrophy. It is not approved by the European Medicines Agency for any indication and is not approved anywhere as a general weight-loss or body-composition treatment for the broader population.
Lab-tested research material
Mechanism
Tesamorelin binds GHRH receptors in the pituitary gland, stimulating the body’s own pulsatile release of growth hormone, which raises IGF-1 and shifts fat metabolism toward breakdown. Visceral fat carries a significantly higher density of growth hormone receptors than subcutaneous fat, so when growth hormone rises, visceral fat cells respond to the resulting lipolytic signal more aggressively than subcutaneous fat cells do (Falutz et al., 2007). A pooled analysis of two Phase 3 trials confirmed the clinical signature of this mechanism directly: 26 weeks of tesamorelin reduced visceral fat by a 15.4% treatment effect versus placebo on CT scan, while subcutaneous fat showed no significant change (Falutz et al., 2010).
Developed by Theratechnologies (Montreal), tesamorelin is mechanistically distinct from exogenous growth hormone: it acts upstream at the pituitary GHRH receptor to stimulate the body's own GH secretion, preserving pulsatile physiological signaling rather than replacing the hormone directly.
GHRH receptor agonism. Binds GHRH receptors on the anterior pituitary with high affinity, stimulating endogenous growth hormone secretion.
Downstream IGF-1. Increased GH raises insulin-like growth factor 1 (IGF-1).
DPP-IV resistance. The N-terminal trans-3-hexenoic acid modification protects against dipeptidyl peptidase-IV cleavage, extending half-life relative to unmodified GHRH (reported ≈26 min vs ≈12 min for sermorelin).
Adipose effects studied. In clinical trials the studied outcome was reduction of visceral adipose tissue, distinct from general weight loss.
Requires intact pituitary axis. Because it acts upstream, activity depends on a functional hypothalamic-pituitary response.
Established mechanism of action for the tesamorelin molecule. Schematic. Research-grade material supplied here is for in-vitro laboratory use only.
State of the Evidence
Tesamorelin has the deepest and most rigorous human evidence base of any compound in this category: two full randomized, double-blind, placebo-controlled Phase 3 trials, pooled and analyzed together across 806 participants, directly supporting its FDA approval. That evidence is specific to the HIV-associated lipodystrophy population it was tested in and to the visceral-fat-reduction indication it’s approved for; it does not extend to general population weight loss or off-label applications.
1. Human — “Metabolic Effects of a Growth Hormone-Releasing Factor in Patients with HIV,” New England Journal of Medicine, 2007. Vol. 357, no. 23, pp. 2359-2370
2. Human — “Effects of Tesamorelin…Pooled Analysis of Two Multicenter, Double-Blind Placebo-Controlled Phase 3 Trials,” Journal of Clinical Endocrinology & Metabolism, 2010. 806 patients, 15.4% treatment effect reduction in visceral adipose tissue versus placebo at 26 weeks. Vol. 95, no. 9, pp. 4291-4304
What the Literature Supports — and What It Doesn’t
Tesamorelin is unusual in this catalogue: unlike most research peptides, the molecule has completed pivotal human trials and holds FDA approval. That approval is real — and it is also narrow. Both halves of that statement matter.
Evidence at a glance
Pivotal trials. In two Phase III trials (Falutz et al.), tesamorelin 2 mg daily reduced visceral adipose tissue by approximately 15% versus placebo over 26 weeks (pooled treatment effect −15.4%, p<0.001, n=806), with accompanying lipid changes.
The approved indication is narrow: reduction of excess abdominal fat in adults with HIV-associated lipodystrophy. Approved 2010 (Egrifta), reformulated 2019 (Egrifta SV), with an F8 formulation approved 2025 (Egrifta WR).
The label states it is not indicated for weight-loss management and is weight neutral. Any framing of tesamorelin as a weight-loss agent contradicts its own prescribing information.
Long-term cardiovascular safety has not been established per the prescribing information. Contraindications include active malignancy, pituitary disruption, and pregnancy.
Use outside HIV lipodystrophy is off-label with thinner evidence; research in non-HIV visceral and hepatic fat contexts is ongoing.
Appropriate characterization: a well-characterized GHRH analogue with genuine Phase III human evidence supporting one specific approved indication. Research-grade material supplied here is not the approved drug product and is intended solely for in-vitro laboratory research.
Regulatory & status notes
Selected references
- 1. Falutz J, et al. Pivotal Phase III trials of tesamorelin in HIV-associated lipodystrophy (pooled analysis, n=806).
- 2. EGRIFTA SV (tesamorelin for injection) US Prescribing Information. FDA/DailyMed.
- 3. PubChem compound record, tesamorelin (CID 16137828).
- 4. FDA approval of the F8 formulation (EGRIFTA WR), 2025.
Safety Information
Research-use compound. This specific compound has FDA-approved prescribing information for its approved indication; consult the approved product labeling for the full clinical safety profile in that context. Evidence strength varies by population and use case — see the Evidence section above.
This is an FDA-approved compound for a specific indication (HIV-associated lipodystrophy); use outside that approved context, dosing, and population has not been evaluated by the FDA. Consult a qualified clinician. For research and educational purposes only, not for human or veterinary use.
Related Compounds
For research and educational purposes only. Not for human or veterinary use.