What it is
Tesamorelin is a stabilised copy of growth hormone-releasing hormone, the brain signal that tells the pituitary gland to release growth hormone. Natural GHRH is destroyed within minutes. Tesamorelin has a small chemical cap on one end that makes it resistant to that breakdown, so a daily injection keeps boosting the body’s own growth hormone pulses.
It is FDA approved under the brand name Egrifta for one narrow purpose: reducing the deep belly fat that builds up in some people with HIV on long-term antiretroviral therapy. It is the only GHRH analogue currently marketed in the United States; an earlier one, sermorelin (Geref), was approved in 1990 and later discontinued.
Tesamorelin is human GHRH(1-44) amide with a trans-3-hexenoyl group on the N-terminal tyrosine, which sterically blocks DPP-4 cleavage at the Ala2-Asp3 bond. It binds the GHRH receptor on somatotrophs and augments pulsatile GH secretion while preserving negative feedback through IGF-1 and somatostatin, which distinguishes it from exogenous GH. Downstream effects include increased lipolysis in visceral adipose tissue and a rise in serum IGF-1 of roughly 100 µg/L at the 2 mg dose in the pivotal trials. Current labels give an elimination half-life of about 8–11 minutes in healthy subjects, but the biological effect on GH pulsatility persists across the dosing interval.
Who made it and when
Theratechnologies, a Montreal company, developed tesamorelin in the early 2000s under the code TH9507. The FDA approved it in November 2010. A more concentrated version, Egrifta SV, followed in November 2018, and a formulation that only needs mixing once a week, Egrifta WR, was approved in March 2025. Since March 2020 the FDA has regulated it as a biologic rather than a conventional drug.
Theratechnologies advanced TH9507 through two pivotal Phase 3 trials in HIV-associated lipodystrophy (2005–2008). FDA approved Egrifta (application 022505) on 2010-11-10 after an advisory committee voted in favour. Egrifta SV (a more concentrated 2 mg-vial formulation) was approved in November 2018, and Egrifta WR (the F8 formulation, 1.28 mg daily from a vial reconstituted weekly) on 2025-03-25 as a supplemental BLA. Because tesamorelin is a 44-residue peptide, it met the statutory definition of a protein, and its NDA was deemed a biologics license application on 2020-03-23. Composition and use patents are held by Theratechnologies; check current expiry status before relying on them.
What the data say
Two large trials in people with HIV showed that daily injections reduced deep abdominal fat by about 11–15% over six months, compared with little or no change on placebo. The fat came back after stopping. A smaller study found it also reduced liver fat in people with HIV and fatty liver disease. There are no approved uses, and no completed trials, in people without HIV for weight loss or body composition.
A pooled analysis of the two Phase 3 trials (n=806) reported a treatment effect of −15.4% on VAT vs placebo at 26 weeks, with triglyceride reduction and no significant change in abdominal subcutaneous fat; IGF-1 rose by a mean 108 ng/mL. VAT reduction was maintained to 52 weeks with continued treatment and was rapidly lost in those switched to placebo. The NAFLD study (n=61) reported an absolute reduction in hepatic fat fraction of 4.1% vs placebo (a 37% relative reduction) and less fibrosis progression over 12 months, without differences in fasting glucose or HbA1c. Labels report HbA1c of 6.5% or higher by week 26 in 5% of tesamorelin vs 1% of placebo participants. No outcome data exist for cardiovascular events.
Regulatory picture
Egrifta is fully FDA approved for its HIV indication. That approval does not extend to any other use. Because tesamorelin has been regulated as a biologic since 2020, and the FDA’s position is that biologics cannot be compounded, pharmacies have no legal route to make copies of it. Products sold online as “research tesamorelin” are not Egrifta.
Tesamorelin acetate is the active ingredient of Egrifta SV and Egrifta WR, licensed under BLA 022505 since the 2020-03-23 transition of protein products from NDAs to BLAs. FDA’s compounding guidance states that biologics cannot be compounded and that federal law provides no pathway for biologics prepared outside an approved BLA, so the drug-shortage exceptions available to 503A and 503B compounders for conventional drugs do not apply. The approved indication is limited to reduction of excess abdominal fat in HIV-infected adults with lipodystrophy; no supplemental indication has been approved. Off-label prescribing of the approved product is a matter of medical practice, not of this site.
