# Tesamorelin: The GHRH-Analogue Research Record, Logged to Source > Tesamorelin is a stabilized 44-amino-acid GHRH analogue that raises the body's own growth hormone and IGF-1. The mechanism, the visceral-fat trial numbers, and exactly where the FDA approval stops. The signaling cascade, the visceral-fat and IGF-1 trial numbers, and the one place the FDA approval stops — read straight from the literature, every figure cited. ## The short version Tesamorelin is a lab-made copy of GHRH (the brain's own "make growth hormone" signal), tweaked so the body's enzymes can't chew it up as fast. It tells the pituitary gland to release more of your own growth hormone, which raises a downstream growth signal called IGF-1 (insulin-like growth factor 1, the messenger the liver makes when growth hormone rises). In studies, this combination burned off deep belly fat. It is FDA-approved as a prescription drug for exactly one thing — excess belly fat in people with HIV-associated fat redistribution — and every other use is off-label. This page summarizes what the published studies actually measured. ## What the tesamorelin record actually shows 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. That single modification blocks the enzyme DPP-IV (dipeptidyl peptidase-IV, the protease that normally inactivates natural GHRH within minutes), which is why tesamorelin lasts long enough in the bloodstream to do its job [8]. It does not supply growth hormone the way an injection of synthetic GH would. Instead it nudges the pituitary to release more of the body's own hormone in its natural pulses, and that growth hormone drives the liver to make IGF-1 [4][7]. The headline numbers come from a pivotal 26-week trial of 412 adults with HIV-associated abdominal fat accumulation: tesamorelin 2 mg/day cut visceral fat (the deep fat packed around the abdominal organs) by 15.2%, while the placebo group gained 5.0%. Triglycerides fell by 50 mg/dL and IGF-1 rose 81.0% [1]. In the 52-week program the visceral-fat reduction held at roughly 18% [2]. These are large, replicated effects — and they were measured in one specific population, which is the whole story of this compound. This site is an editorial digest. It maps [how tesamorelin works](/mechanism), the [half-life and pharmacokinetics](/pharmacokinetics), the [visceral-fat research](/research), and the [side effects and contraindications](/faq) onto the studies that produced each figure, with the [full reference list](/references) at the end. ## What does tesamorelin do? Tesamorelin amplifies the body's own pulsatile growth-hormone secretion and raises IGF-1, and those two signals together promote lipolysis — the breakdown of stored fat — preferentially in visceral adipose tissue [4][1]. The selectivity is the notable part. In the HIV trials the deep abdominal fat shrank while subcutaneous fat (the fat just under the skin) and overall BMI changed little [1]. A 2021 imaging analysis added a second dimension: over 26 weeks the drug also raised the CT density of both visceral and subcutaneous fat (VAT +6.2 vs +0.3 Hounsfield units on placebo, P<0.0001), a marker of improved fat-tissue quality that moved independently of the change in fat quantity [12]. The effect is also reversible. In the 52-week program, visceral fat reaccumulated once dosing stopped — the benefit was contingent on continued administration [2]. A 2026 meta-analysis of five randomized trials in HIV-associated lipodystrophy put the pooled visceral-fat reduction at a mean difference of -27.71 cm2 and the hepatic-fat reduction at -4.28%, with lean body mass up 1.42 kg and no serious adverse events reported [15]. What tesamorelin does not do is also worth stating plainly. It is not a general weight-loss agent — total body weight and subcutaneous fat barely moved in the trials [1]. It does not supply growth hormone; it amplifies the body's own pulses [4][7]. And its measured effects come from one studied population. The mechanism, the kinetics, and the trial endpoints are each laid out in their own pages, but the one-line answer is: it shifts the body's growth-hormone axis to burn deep abdominal fat, for as long as it is taken. ## Tesamorelin as a research peptide As a tesamorelin peptide studied in the laboratory, the molecule is defined precisely: molecular weight 5135.9 Da, CAS 218949-48-5, a single approved indication. Research-grade tesamorelin supplied for laboratory work is not the approved finished drug product — it lacks the purity and potency oversight that the marketed prescription product carries, and nothing here describes a medicine to self-administer. In the published human work the only route studied is subcutaneous injection into the abdomen, at 2 mg once daily [1][3], with 1 mg/day arms appearing in a cognition trial and a type-2-diabetes safety study. The doses studied in the trials are summarized on the [dosage page](/dosage); none of it is a dosing instruction. What makes the peptide unusual for its class is the depth of human data behind it — two pivotal Phase 3 trials, a JAMA liver-fat trial, and a population-pharmacokinetic analysis, all anchored to one indication. Most of the peptides discussed in this corner of the literature — growth-hormone secretagogues and GHRH fragments — have only animal data behind them. Tesamorelin is the exception that proves the rule: a GHRH analogue that ran the full clinical gauntlet and earned an approval, because a specific, measurable, unmet need (visceral fat in HIV-associated lipodystrophy) gave the trials a clean endpoint. That history is exactly why it is useful as a reference point, and exactly why its evidence stops at one population's door. ## Is tesamorelin FDA approved? Yes — but only for one indication. Tesamorelin was approved in the United States under NDA 022505 in November 2010 to reduce excess abdominal fat in HIV-infected adults with antiretroviral-associated lipodystrophy [5]. That is the entire scope of the approval. Every other use — general or cosmetic fat loss, anti-aging, growth-hormone optimization, bodybuilding, non-HIV fatty-liver disease — is off-label and not FDA-approved. Saying "tesamorelin is approved" without that boundary is misleading; saying it is "not approved" is also wrong. The precise statement is: approved for HIV-associated lipodystrophy, investigational and off-label for anything else. Tesamorelin is also prohibited in sport under the World Anti-Doping Agency Prohibited List (category S2), in and out of competition. --- A shadowless data sheet of the tesamorelin record — the GHRH-receptor cascade and the visceral-fat numbers logged to source, the FDA approval marked exactly where it stops and the off-label boundary left in plain view; no clinic behind the grid and nothing here dispensed or sold.