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Tesamorelin: key facts
Evidence level FDA-approved
Approved as a medicineExcess abdominal fat in HIV-associated lipodystrophy
Randomized trials on PubMed21
Registered human trials24
People use it forReducing abdominal fat in HIV lipodystrophy (the approved use); promoted off-label for body composition.
In tested sportProhibited
In one sentence: Tesamorelin is an approved medicine (excess abdominal fat in HIV-associated lipodystrophy). Its strongest evidence is FDA approval backed by large trials, with 21 randomized trials listed on PubMed and 24 registered human trials.
FDA-approved as Egrifta for reducing excess visceral abdominal fat in HIV-associated lipodystrophy. Clinical trials demonstrate selective visceral fat reduction without lowering subcutaneous fat.
What it is
Tesamorelin (brand names Egrifta and Egrifta SV, code name TH9507) is a synthetic 44-amino-acid peptide analog of human growth hormone-releasing factor (GHRH). It is modified with a trans-3-hexenoyl group at the N-terminus to improve stability and resist degradation by dipeptidyl peptidase-4 (DPP-4). In November 2010, the US FDA approved tesamorelin for daily subcutaneous injection to reduce excess visceral abdominal adipose tissue in adults with HIV-associated lipodystrophy.
How it is thought to work
Tesamorelin binds specifically to GHRH receptors on anterior pituitary somatotrophs, stimulating the endogenous synthesis and pulsatile release of growth hormone (GH). Elevated GH acts on the liver to stimulate insulin-like growth factor 1 (IGF-1) and directly triggers lipolysis in adipocytes, with a selective affinity for metabolically active visceral fat over subcutaneous fat depots. Because endogenous negative feedback by somatostatin remains intact, tesamorelin maintains physiological GH pulsatility rather than causing constant high levels.
What the studies found5 studies explained
Two pivotal Phase 3 randomized, double-blind, placebo-controlled trials (412 and 404 HIV patients with excess abdominal fat) published in The New England Journal of Medicine and JCEM showed that 2 mg daily for 26 weeks reduced visceral adipose tissue (VAT) by 15.2% to 17.5% measured by CT scan, compared to an increase with placebo. Subcutaneous adipose tissue was unaffected. A 12-month multicenter RCT published in The Lancet HIV (2019) demonstrated that tesamorelin also significantly reduced hepatic fat fraction by 37% in HIV patients with non-alcoholic fatty liver disease (NAFLD) and prevented the progression of liver fibrosis.
412 HIV-infected patients with excess abdominal fat accumulation
What they found
Tesamorelin 2 mg daily subcutaneously for 26 weeks reduced visceral adipose tissue by 15.2% (vs +5.0% for placebo, p < 0.001) as measured by CT scan, with no significant change in subcutaneous adipose tissue. Trunk fat and waist circumference decreased significantly.
Limitations
26-week initial duration; studied exclusively in patients with HIV-associated lipodystrophy on stable antiretroviral therapy, not in the general population.
humanRandomized, double-blind, 52-week extension study of phase 3 trials
Who / how many
404 HIV-infected patients who completed the initial 26-week phase 3 trial
What they found
Patients continuing tesamorelin maintained a 17.5% reduction in visceral fat at 52 weeks, whereas patients switched to placebo re-accumulated visceral fat back toward baseline.
Limitations
Visceral fat re-accumulation upon cessation indicates chronic treatment is needed to maintain body composition changes; mild increases in IGF-1 were observed.
Tesamorelin significantly reduced visceral adipose tissue and ectopic liver fat stores, along with favorable changes in circulating adipokines, over 6 months of daily therapy.
Limitations
Small sample size (48 patients); focused on imaging and metabolic biomarkers rather than long-term cardiovascular clinical endpoints.
53 HIV-infected patients with impaired fasting glucose or type 2 diabetes and abdominal fat accumulation
What they found
Tesamorelin 2 mg daily for 12 weeks reduced visceral fat (-15%) without deteriorating insulin sensitivity or glycemic control (measured by 2-hour oral glucose tolerance test).
Limitations
Short 12-week study duration and small sample size in a specialized diabetic subgroup.
20 trials on ClinicalTrials.gov list Tesamorelin as an intervention; the most advanced are shown. Registration is not evidence of benefit: many trials are ongoing, unpublished or never reported results.
Data pulled from the ClinicalTrials.gov API. Check sponsors: several newer peptide registrations come from companies that also sell the product.
European research
94 records in Europe PMC mention Tesamorelin in the title or abstract. Of the 17 most-cited with European author affiliations that we sampled, the most common countries were UK (4), Germany (4), Belgium (3), Italy (2).
Adverse events in clinical trials include injection site reactions (erythema, pruritus, or pain in ~17%), arthralgias (13%), peripheral edema (6%), and myalgias, primarily resulting from fluid shifts associated with elevated GH and IGF-1. Because GH has anti-insulin effects, glucose tolerance must be monitored; small increases in fasting glucose and HbA1c have been observed. Because GH and IGF-1 are mitogenic, tesamorelin is contraindicated in patients with active malignancy or a history of pituitary neoplasm.
FDA-approved in November 2010 (brand names Egrifta and Egrifta SV) for the reduction of excess visceral abdominal fat in HIV-infected patients with lipodystrophy. Prescription-only. Not approved for general weight loss or bodybuilding.
Canada
Authorized by Health Canada as Egrifta for HIV-associated lipodystrophy.
European Union
Not authorized in the European Union. An application for marketing authorization was submitted to the EMA but withdrawn in 2012 by the manufacturer after questions regarding risk-benefit balance.
Sport (WADA)
Prohibited at all times in sport under Category S2 (Peptide Hormones, Growth Factors, Related Substances, and Mimetics: Growth Hormone Secretagogues).
Is tesamorelin FDA-approved for weight loss or bodybuilding?
No. Tesamorelin (Egrifta) is FDA-approved solely for reducing excess visceral abdominal fat in adults with HIV-associated lipodystrophy. It is not approved for general obesity or athletic performance.
How does tesamorelin differ from synthetic growth hormone (somatropin)?
Somatropin is recombinant human growth hormone itself, which bypasses the pituitary and overrides the body's natural feedback loops. Tesamorelin is a GHRH analog that stimulates the pituitary to release the body's own growth hormone in natural, pulsatile bursts while preserving somatostatin feedback.
What happens when tesamorelin is stopped?
Clinical extension trials showed that when tesamorelin was discontinued after 26 or 52 weeks, visceral adipose tissue re-accumulated back toward baseline levels over several months, indicating that ongoing treatment is necessary to maintain benefits.
