TESAWhat the studies show

Q: What kind of evidence exists for tesamorelin?

Large human trials. Two randomised, placebo-controlled phase 3 trials and two smaller randomised trials, all in people with HIV, supporting one approved use; the evidence outside HIV is a single small cognitive study, and nothing is known about long-term use.

The one GHRH analogue that became an approved drug: Egrifta, for abdominal fat in HIV lipodystrophy, on the strength of two 26-week phase 3 trials.

6 min read · Large human trials · Updated November 2026

In short

Name: tesamorelin (sold by Progression Labs as TESA)
Evidence: Large human trials
Bottom line: Two randomised, placebo-controlled phase 3 trials and two smaller randomised trials, all in people with HIV, supporting one approved use; the evidence outside HIV is a single small cognitive study, and nothing is known about long-term use.

Before you read this

This guide explains what published studies found. That is all it is.

It is not medical advice and it is not instructions for using anything. Where a dose appears, we are reporting what a named study gave the people or animals in it — a fact about the study, not an instruction to you.

The compounds here are not approved by the FDA for use in people and are sold for laboratory research only. A study tells you what happened to the subjects in it; it does not tell you what would happen to you. Talk to a doctor first.

What it is

Tesamorelin is the full 44-amino-acid human growth hormone releasing hormone (GHRH) with a small fatty-acid group, trans-3-hexenoic acid, attached to its first amino acid. That cap blocks the enzyme that normally destroys GHRH within minutes of entering the blood, so the peptide lasts long enough to be given once a day under the skin ¹. It was developed by Theratechnologies in Montreal and, in November 2010, the U.S. Food and Drug Administration approved it under the brand name Egrifta for one use: reducing excess abdominal fat in HIV-infected patients with lipodystrophy ². It is the only GHRH analogue that has reached approval as a treatment, and its label says explicitly that it is not indicated for weight loss ².

The studies below call this molecule tesamorelin. Progression Labs sells it as TESA; the guide uses the store's name and the papers use theirs.

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The phase 3 trials

The first phase 3 trial was published in the New England Journal of Medicine in 2007. It enrolled 412 people with HIV and excess abdominal fat and randomised them to tesamorelin 2 mg under the skin once a day or placebo for 26 weeks, measuring visceral fat by CT scan ¹. Visceral fat fell by 15.2% in the tesamorelin group and rose by 5.0% in the placebo group. Triglycerides fell, IGF-1 rose, and patients reported their abdomens looked and felt better on a validated questionnaire ¹. Subcutaneous fat, the fat under the skin, changed little, which is what a drug acting through the growth hormone axis would be expected to do.

A second phase 3 trial of the same design followed, and a 2010 paper in the Journal of Clinical Endocrinology & Metabolism pooled the two, with the safety extension in which patients were re-randomised at 26 weeks to continue or switch to placebo ³. The pooled result confirmed the visceral fat reduction. The extension answered the next question: patients who stayed on tesamorelin held the loss through 52 weeks, and patients switched to placebo regained the visceral fat they had lost ³. The effect lasts as long as the drug does.

Liver fat

Visceral fat and liver fat travel together, so a group at Massachusetts General Hospital tested tesamorelin against placebo in HIV patients with abdominal fat accumulation for six months, measuring liver fat by magnetic resonance spectroscopy. The 2014 report in JAMA found less liver fat and less visceral fat in the tesamorelin group ⁴. A 12-month trial in HIV patients with diagnosed fatty liver disease, published in The Lancet HIV in 2019, found the same reduction in liver fat and, on paired biopsies, less progression of fibrosis in the tesamorelin group than in the placebo group ⁵. Both trials were small and both were in people with HIV.

Side effects in the trials

The most common adverse events in the phase 3 trials were injection-site reactions, joint pain, swelling of the hands and feet, and tingling, the ones expected from raising growth hormone ¹³. IGF-1 rose in nearly everyone, and the label asks prescribers to monitor it and to stop the drug if it stays too high. Glucose rose slightly in some patients. The label lists active cancer and pregnancy as contraindications, because growth hormone and IGF-1 promote cell growth ².

What is not known

Every large trial of tesamorelin is in people with HIV. Outside that group the published work is small: a 20-week study in healthy older adults and adults with mild cognitive impairment reported better scores on some cognitive tests, with a rise in IGF-1, in 2012 ⁶. There is no trial of tesamorelin for body composition in healthy adults, no long-term outcome data beyond a year, and no evidence that the visceral-fat finding transfers to anyone without HIV lipodystrophy. The drug is approved for one condition, and the evidence is for that condition.

What these studies are, and aren't

Large human trials. Two randomised, placebo-controlled phase 3 trials and two smaller randomised trials, all in people with HIV, supporting one approved use; the evidence outside HIV is a single small cognitive study, and nothing is known about long-term use.