What does tesamorelin do? What published studies found

What does research show tesamorelin does in the body?

The Egrifta SV label (DailyMed record updated 29 July 2026, read 14 October 2026) reports that, in laboratory tests, tesamorelin binds and stimulates human growth-hormone-releasing hormone (GHRH) receptors with similar potency to the natural hormone, an in-vitro cell result that does not by itself show an effect in people (Egrifta SV label, section 12.1). GHRH is the brain signal that tells the pituitary gland to release growth hormone. In a study of 13 healthy men, after two weeks of tesamorelin, mean overnight growth hormone rose by 0.5 µg/L and IGF-1 rose by 181 µg/L, while fasting glucose and insulin-stimulated glucose uptake did not change significantly, results for those 13 men only and from an abstract that describes no placebo group, so a small study with no control (Stanley et al., Journal of Clinical Endocrinology and Metabolism, 2011). Tesamorelin is the 44-amino-acid GHRH sequence with a hexenoyl group added at one end, not growth hormone itself (Egrifta SV label, section 11).

The pituitary gland keeps growth hormone in store, and GHRH is the signal that releases some. The Stanley et al. study assessed the 13 men at baseline, after two weeks of tesamorelin and after two weeks of withdrawal (Journal of Clinical Endocrinology and Metabolism, 2011).

A 2026 narrative review calls tesamorelin the most comprehensively characterised GHRH analogue from a regulatory and clinical-trial perspective (Dominikowski et al., Frontiers in Endocrinology, 2026). The Egrifta SV label gives a mean elimination half-life of 8 minutes in healthy subjects, with no participant number (Egrifta SV label, section 12.3).

Evidence limits

What have tesamorelin studies not shown?

Time and size set other limits. The label's pivotal trials followed people for 52 weeks at most, and the label's limits of use say long-term cardiovascular safety has not been established (Egrifta SV label, sections 1 and 14). Results also vary between trials: a 2026 meta-analysis of four randomised trials in 909 adults with HIV lipodystrophy reported heterogeneity of I² = 74% for the visceral-fat result, in those four trials only (Ditta et al., Journal of the International Association of Providers of AIDS Care, 2026).

A 6-month open-label trial of 73 adults with HIV and abdominal obesity reported no significant between-group difference in neurocognitive performance between tesamorelin and standard of care (p = 0.673), though waist size fell more with tesamorelin (median difference -2.7 cm); it had no placebo group and its authors note insufficient power (Ellis et al., The Journal of Infectious Diseases, 2025).

What outcomes changed in tesamorelin trials?

In a pooled analysis of two randomised placebo-controlled 26-week trials in 806 adults with HIV and excess abdominal fat, the treatment effect at 26 weeks was 15.4% lower visceral fat, 12.3% lower triglycerides and a 7.2% lower total-cholesterol-to-HDL ratio, with no significant change in subcutaneous fat (the layer under the skin), results for those adults only (Falutz et al., Journal of Clinical Endocrinology and Metabolism, 2010). In the second trial, of 404 adults with HIV, trunk fat, waist circumference and waist-hip ratio improved against placebo and IGF-1 increased, in that trial only (Falutz et al., Journal of Acquired Immune Deficiency Syndromes, 2010).

People and doctors also rated appearance. In the second randomised trial of 404 adults with HIV, patient-rated distress about belly appearance and physician-rated belly profile both scored better with tesamorelin than with placebo, as subjective ratings in that trial only (Falutz et al., Journal of Acquired Immune Deficiency Syndromes, 2010).

A 2026 meta-analysis of four randomised trials in 909 adults with HIV lipodystrophy reported visceral fat 21.47 cm² lower, waist 1.61 cm smaller, trunk fat 1.20 kg lower and lean body mass 1.42 kg higher with tesamorelin, alongside growth-hormone-related adverse effects, in those four trials only (Ditta et al., Journal of the International Association of Providers of AIDS Care, 2026). The table below lists the trials behind these numbers.

How much visceral fat did tesamorelin trials measure losing?

In the two pivotal 26-week randomised trials of adults with HIV (273 on tesamorelin and 137 on placebo in the first, 270 and 126 in the second), CT-scan visceral fat was 31 cm² lower with tesamorelin than with placebo in the first trial (95% confidence interval 24 to 39) and 21 cm² lower in the second (12 to 29), in those two trials only (Egrifta SV label, section 14, Table 2). In the same two trials of adults with HIV (273 and 137; 270 and 126), the label's mean treatment differences in percent change were -20% (95% confidence interval -24 to -15) and -12% (-16 to -7), in those two trials only (Egrifta SV label, section 14, Table 2). In the first published trial, visceral fat fell 15.2% against a 5.0% rise among 412 adults with HIV, in that trial only (Falutz et al., New England Journal of Medicine, 2007). In the second published trial, it fell 10.9% against 0.6% among 404 adults with HIV, in that trial only (Falutz et al., Journal of Acquired Immune Deficiency Syndromes, 2010).

Averages hide spread. In the pooled analysis of 806 adults with HIV, visceral fat changed by -24 ± 41 cm² on tesamorelin, so the spread around the mean was wide, in those adults only (Falutz et al., Journal of Clinical Endocrinology and Metabolism, 2010). The FDA defined a responder in these two phase III trials, in advance, as someone whose visceral fat fell by at least 8% (Fourman et al., AIDS, 2017).

Other groups gave other numbers. In a 6-month randomised trial of 50 adults with HIV, which its authors call preliminary, visceral fat changed by -34 cm² with tesamorelin and +8 cm² with placebo (Stanley et al., JAMA, 2014). In a 12-month randomised trial of 60 abdominally obese adults with reduced growth hormone secretion, it changed by -16 cm² against +19 cm², in that group only (Makimura et al., Journal of Clinical Endocrinology and Metabolism, 2012). Each number belongs to its own group.

What did trials record for body weight with tesamorelin?

In the two pivotal 26-week randomised trials of adults with HIV (273 on tesamorelin and 137 on placebo in the first, 270 and 126 in the second), the average weight change with tesamorelin against placebo was -0.4 kg against 0.0 kg in the first trial and +0.5 kg against +0.3 kg in the second, and the treatment differences (-0.4 kg and +0.2 kg) had confidence intervals that included zero, in those two trials only (Egrifta SV label, Table 3). The label states tesamorelin 'is not indicated for weight loss management as it has a weight neutral effect' (Egrifta SV label, section 1).

In the two pivotal trials of adults with HIV (273 on tesamorelin and 137 on placebo in the first, 270 and 126 in the second), trunk fat fell by 1.0 kg and 0.8 kg with tesamorelin against rises of 0.4 kg and 0.2 kg with placebo, while lean body mass rose by 1.3 kg and 1.2 kg against falls of 0.2 kg and 0.03 kg, in those two trials only (Egrifta SV label, section 14). The label separately lists fluid retention among its warnings (Egrifta SV label, section 5.3). A 2026 meta-analysis of five randomised trials in adults with HIV, whose abstract gives no participant total, reported no significant reduction in body-mass index, in those five trials only (Badran et al., Obesity Research & Clinical Practice, 2026).

The label's indication concerns excess abdominal fat in adults with HIV (Egrifta SV label, section 1). The side-effects page lists the fluid-related events.

What did trials record for lean body mass and muscle with tesamorelin?

In the two pivotal randomised trials of adults with HIV (273 on tesamorelin and 137 on placebo in the first, 270 and 126 in the second), average lean body mass rose by 1.3 kg in the first trial and 1.2 kg in the second with tesamorelin, while it fell by 0.2 kg and 0.03 kg with placebo, in those two trials only (Egrifta SV label, section 14). A 2026 meta-analysis of five randomised trials in adults with HIV, whose abstract gives no participant total, reported lean body mass 1.42 kg higher with tesamorelin, in those five trials only (Badran et al., Obesity Research & Clinical Practice, 2026). The label separately lists fluid retention among its warnings (Egrifta SV label, section 5.3).

A separate analysis of CT scans looked at muscle itself. In a secondary exploratory analysis of two randomised trials in adults with HIV, tesamorelin was associated with denser trunk muscle and, in several muscle groups, larger muscle area at 26 weeks in 193 tesamorelin responders (visceral fat down 8% or more) against 148 placebo participants with available images, and because the tesamorelin group was restricted to responders the comparison is not like-for-like (Adrian et al., The Journal of Frailty & Aging, 2019).

Strength and physical performance were not the measures in these records. A 2026 narrative review highlights uncertainty around putative performance and recomposition effects of growth-hormone-axis peptides (Dominikowski et al., Frontiers in Endocrinology, 2026).

Does visceral fat come back after stopping tesamorelin?

In the 26-week extension of the two pivotal randomised trials in adults with HIV, participants re-randomised to placebo had visceral fat change by +22% in the first trial (50 people) and +16% in the second (85 people), while those who stayed on tesamorelin changed by 0% (154 people) and -5% (92 people), in these selected extension participants only (Egrifta SV label, Table 4). Falutz et al. wrote that the first-phase improvements in the second trial of 404 adults with HIV were 'rapidly lost' after the switch to placebo, in that trial only (Journal of Acquired Immune Deficiency Syndromes, 2010). Visceral fat is the fat packed around the organs inside the abdomen.

The design explains the numbers. After 26 weeks on tesamorelin, some adults carried on (the T-T group) and some switched to placebo (the T-P group), without knowing which. In the second trial of 404 adults with HIV, the authors reported visceral fat reduced by approximately 18% at 12 months in the adults who continued tesamorelin, a result for that group only (Falutz et al., Journal of Acquired Immune Deficiency Syndromes, 2010).

Among adults with HIV in the two phase III trials who had high liver enzymes at the start, the enzyme improvements in visceral-fat responders persisted at 52 weeks even after the switch to placebo, an association that does not show tesamorelin caused it; the two trials enrolled 806 adults, but the abstract gives no relevant subgroup count (Fourman et al., AIDS, 2017). The side-effects page covers what else is recorded after stopping.

How did trials measure response to tesamorelin?

The primary measure in both pivotal trials of adults with HIV was the percent change in visceral fat on a CT scan at the L4-L5 level of the spine, from the start to week 26 (Egrifta SV label, section 14). The FDA defined a responder in these trials as someone whose visceral fat fell by at least 8% (Fourman et al., AIDS, 2017). Waist size, IGF-1, blood fats and patient-rated belly distress were secondary or other measures, and the 26-week extension re-randomised adults to blinded therapy with either tesamorelin or placebo (Egrifta SV label, section 14).

The responder threshold of at least 8% was defined a priori by the FDA for the two phase III trials of 806 adults with HIV (Fourman et al., AIDS, 2017). It is a measurement convention for those trials, and it says nothing about any person outside them.

Have studies tested tesamorelin for hair growth?

The sources searched on 14 October 2026 did not find a published human study of tesamorelin and hair growth. A PubMed search of titles and abstracts that day, pairing tesamorelin with hair, hair loss, hair growth or alopecia, returned no records, and a second search pairing tesamorelin with scalp, baldness or follicle also returned none. The label's indication concerns abdominal fat in adults with HIV (Egrifta SV label, section 1), and none of the trial abstracts read for this page names hair as an outcome.

An empty search is a statement about what the databases searched indexed, not proof that nothing was ever studied or could happen. It means that two PubMed searches on one day found no human trial to cite on tesamorelin and hair. The same reading applies to the other questions this page marks as untested.

Which randomised trials measured visceral fat with tesamorelin in HIV?

Four randomised placebo-controlled trials in the sources read measured visceral fat with tesamorelin in adults with HIV: a 12-week trial of 61 adults (Falutz et al., AIDS, 2005), two pivotal trials of 412 and 404 adults over 26 weeks (Falutz et al., New England Journal of Medicine, 2007; Falutz et al., Journal of Acquired Immune Deficiency Syndromes, 2010), and a 6-month trial of 50 adults at one hospital (Stanley et al., JAMA, 2014). Two 2026 meta-analyses pooled four and five trials (Ditta et al., 2026; Badran et al., 2026). The table below lists each.

Registry numbers help anyone check the source. The first pivotal trial is NCT00123253 on ClinicalTrials.gov, the 2014 trial is NCT01263717 and the 12-month liver trial is NCT02196831 (records read 14 October 2026). ClinicalTrials.gov records the product's manufacturer as lead sponsor of NCT00123253, which is worth knowing when reading an approval trial.

Has a randomised trial compared tesamorelin with sermorelin?

The sources searched on 14 October 2026 did not find a randomised trial comparing tesamorelin with sermorelin. A PubMed search for both names that day returned 13 records, and by title none is a head-to-head trial: four are reviews and nine are laboratory methods for detecting these peptides, such as Dominikowski et al., Frontiers in Endocrinology, 2026 and Vasylieva et al., Sexual Medicine Reviews, 2026. The 2026 Frontiers narrative review places tesamorelin in its top evidence tier because of its randomised trials in HIV, a ranking by quality of evidence rather than by which peptide works better.

The tesamorelin and sermorelin comparison page sets the two molecules side by side, with their structures and regulatory records, and states that the records reviewed do not support a like-for-like pharmacokinetic comparison or a ranking drawn from separate studies of different people.

Do these study findings apply to research-use tesamorelin?

No. The findings on this page describe tesamorelin received by enrolled adults under medical care in clinical trials. Research-use tesamorelin reference material is a laboratory compound, is not a medicine, is not a substitute for one, and is not for human or animal use. The trial results describe what happened inside those trials, in those people, and they say nothing about any material outside them. Nothing in this article suggests otherwise.

This site's catalogue lists tesamorelin reference material as freeze-dried laboratory stock, with a historical sample report that covers only the sample it names. The tesamorelin approved as a medicine is a separate, regulated product.