What is Tesamorelin?
Tesamorelin is a stabilized synthetic analog of GHRH (growth hormone-releasing hormone) with the same sequence as the 44 amino acids of native GHRH, modified by the addition of a trans-3-hexenoic acid group at the N-terminal that increases its stability and half-life.
Developed by Theratechnologies, it was FDA approved in 2010 as Egrifta for the treatment of HIV-associated lipodystrophy — specifically the abdominal visceral fat accumulation that occurs as a side effect of antiretroviral therapy.
It is the only GH secretagogue with FDA approval for a metabolic adiposity indication.
Mechanism and effect on visceral fat
Tesamorelin acts on the GHRHR receptor in the pituitary, increasing GH secretion. GH has direct lipolytic effects on adipose tissue, with visceral fat being particularly sensitive to these effects.
Phase 3 trial data (NEJM, 2010):
- Reduction in abdominal visceral fat: 15.2% average over 26 weeks vs. 1.6% with placebo.
- No changes in fasting glucose or HbA1c in the short term.
- No negative effects on antiretroviral therapy.
Investigated off-label use
Cognition in older adults: A double-blind trial in older adults with mild cognitive impairment (Harvard DSS, 2019) showed improvements in executive function and visuospatial memory with tesamorelin 1 mg/day over 20 weeks, possibly mediated by central IGF-1.
Body composition: The same lipolytic mechanism is of interest for visceral fat reduction in the general population without HIV, although no approval exists for this indication.
Tesamorelin vs. other GHRH secretagogues
| Feature | Tesamorelin | CJC-1295 No DAC | Sermorelin |
|---|---|---|---|
| Sequence | Modified GHRH 1-44 | Modified GHRH 1-29 | Native GHRH 1-29 |
| Half-life | ~26 min | ~30 min | ~11 min |
| FDA approval | Yes (Egrifta) | No | No (discontinued) |
| Clinical evidence | High (Phase 3) | Low | Moderate |
Reconstitution (reference)
With 5 mg + 2.0 mL bacteriostatic water: 1 unit U-100 ≈ 25 mcg.
Adverse effects
Reported in Phase 3 trials: peripheral edema (6%), arthralgias (4%), paresthesias (4%), transient hyperglycemia (dose-dependent). Generally well tolerated.
Egrifta requires a medical prescription. Off-label use only under specialized medical supervision.
Reported protocol (research reference)
| Vial sizes | 5 mg, 10 mg, 20 mg |
|---|---|
| Reported dose | Approved protocol (Egrifta): 2 mg SC once daily. Off-label use investigated at the same dose. |
| Half-life | ~26 minutes. |
| FDA status | FDA approved |