Read through its pharmacokinetics, tesamorelin is a stabilized GHRH(1-44) analogue that leaves the plasma in minutes yet keeps signaling for hours.

The short version

Tesamorelin is a lab-made copy of the body's own "make growth hormone" signal — GHRH (the hormone the brain uses to tell the pituitary gland to release growth hormone, or GH). A small chemical tweak on one end keeps the molecule from being chewed up as fast as the natural version, so it works longer. In studies it nudges the pituitary to release the body's own GH in bursts, which raises IGF-1 (a growth signal the liver makes when GH rises) and helps break down deep belly fat. It is FDA-approved for one narrow use only: reducing excess abdominal fat in people with HIV-associated lipodystrophy. Every other use is off-label.

Tesamorelin: the peptide and where the evidence comes from

Tesamorelin is a synthetic 44-amino-acid analogue of human growth hormone-releasing hormone — GHRH(1-44) — carrying a trans-3-hexenoic acid group on its N-terminus (the chain's starting end) that resists cleavage by DPP-IV, the enzyme that rapidly inactivates natural GHRH. That single modification is the whole design: native GHRH is destroyed within minutes, while the stabilized analogue survives long enough to do its work. As a research peptide it carries the identifiers CAS 218949-48-5, FDA UNII 9MM72X02HA, ATC code H01AC06, and a molecular weight of 5,135.9 Da.

The evidence base is unusually deep for this compound class. Tesamorelin is supported by two pivotal Phase 3 randomized controlled trials in HIV-associated lipodystrophy ^[1][2], an earlier dose-ranging Phase 2 trial ^[7], a JAMA trial measuring liver fat ^[3], a mechanistic study in healthy men ^[4], dedicated population-pharmacokinetic and PK/PD analyses ^[8][9], and a 2026 meta-analysis pooling five RCTs ^[12]. The tesamorelin peptide is one of the few in its category with human trial data at this scale — which is exactly what makes it worth reading carefully rather than guessing at. This site summarizes that record; it does not sell, supply, or recommend the compound. The pages here describe research-grade tesamorelin as it appears in the literature, not a medicine to self-administer.

What the trials report tesamorelin does

In the pivotal 26-week Phase 3 trial of 412 HIV patients with abdominal fat accumulation, tesamorelin 2 mg/day reduced visceral adipose tissue — VAT, the deep fat packed around the abdominal organs — by 15.2%, while the placebo group's VAT rose 5.0% ^[1]. Triglycerides fell by 50 mg/dL versus a 9 mg/dL rise on placebo, and IGF-1 increased 81.0% ^[1]. Over the full 52-week program, the VAT reduction was sustained at -18% ^[2]. The effect was dose-related from the start: in an earlier 12-week dose-ranging trial, IGF-1 rose 48% at 1 mg/day and 65% at 2 mg/day versus placebo, alongside trunk-fat reduction ^[7]. A 2026 meta-analysis of five RCTs put the pooled effect at -27.71 cm2 of visceral fat (95% CI -38.37 to -17.06; P<0.001), alongside reductions in trunk fat and hepatic fat fraction and a gain in lean body mass ^[12].

Two qualifiers belong in the same breath as those numbers. First, the effect is selective: tesamorelin reduces visceral fat largely without changing subcutaneous fat or BMI ^[1]. Second, it is contingent — visceral fat reaccumulates within weeks of stopping ^[2]. These are documented outcomes in HIV-associated lipodystrophy cohorts, not a general weight-loss claim and not a recommendation.

What is tesamorelin used for, and is it FDA approved?

What is tesamorelin used for?

Tesamorelin is FDA-approved for one indication: reducing excess abdominal fat in HIV-infected adults with lipodystrophy ^[5]. Lipodystrophy here means the abnormal fat redistribution — including visceral fat buildup — that can accompany HIV and antiretroviral therapy. Every other application, including general or cosmetic fat loss, anti-aging, GH optimization, and non-HIV fatty-liver disease, is off-label and not FDA-approved.

Is tesamorelin FDA approved?

Yes, but narrowly. Tesamorelin was approved in the United States in 2010 (NDA 022505) to reduce excess abdominal fat in HIV patients with antiretroviral-related lipodystrophy ^[5]. There is no FDA indication outside that population. "Approved" and "approved for your situation" are different statements, and for tesamorelin only the first is true outside HIV-associated lipodystrophy. The detail sits on the is tesamorelin FDA approved? entry.

How to read this digest

The dealt lens of this site is pharmacokinetics, and that lens organizes everything. The PK story is a study in contrast: a population analysis estimated apparent plasma clearance at roughly 1,060 L/h, so the peptide is a brief, bright event in the blood ^[8], yet a PK/PD model showed it drives GH in episodic pulses whose downstream IGF-1 elevation persists across the once-daily interval ^[9]. Brief light, lingering signal — the whole tesamorelin half-life and pharmacokinetics page is built on that distinction.

From here, the mechanism of action page traces GHRH-receptor agonism through the GH/IGF-1 axis and lays out what the visceral-fat trials report; the structural comparison sets out how tesamorelin compares with sermorelin; the dosage page records the studied doses in the literature; and the FAQ collects side effects and contraindications with direct, cited answers. Every figure resolves to the full reference list.