Tesamorelin and sermorelin are often sold as two strengths of the same idea, and at the receptor they are. Both copy the hormone the hypothalamus uses to tell the pituitary to release growth hormone. Where they part company is the evidence, which differs in size, in the people studied and in what was measured.
This page compares the two molecules and their records. Each has its own page on what the trials found: tesamorelin’s Egrifta trials and whether sermorelin works. The sleep question, for readers arriving from the sleep goal, is covered on the sermorelin page.
Two copies of one hormone
Natural growth-hormone-releasing hormone is 44 amino acids long. Sermorelin is its first 29, which a 1999 review describes as the shortest synthetic peptide with the full biological activity of the natural hormone [3]. It acts on the pituitary to release growth hormone, which the liver answers with IGF-1.
Tesamorelin keeps all 44 amino acids and adds a hexenoyl group, a six-carbon chain, to the first one [1]. The label states that it binds the human receptor with potency similar to the natural hormone. Researchers describe it as a stabilized analog [7]. Even so, the label gives its half-life after an injection under the skin as about 11 minutes [1].
Both act on the same receptor, so both need a working pituitary to do anything. The tesamorelin label rules it out in people whose pituitary axis has been disrupted [1], and one of sermorelin’s approvals was a test of whether the pituitary could respond at all [2].
Two very different regulatory histories
Tesamorelin was approved by the FDA in November 2010 [4]. Its label covers one use: reducing excess abdominal fat in adults with HIV-associated lipodystrophy [1]. It remains on the market as Egrifta.
On March 23, 2020, Egrifta’s approval was deemed a biologics license [11]. The FDA states that products in that transition are not eligible for the exemptions that allow pharmacies to compound drugs [12]. Tesamorelin is available lawfully only as the brand product.
Sermorelin was approved twice under the name GEREF. One approval, from 1990, was a diagnostic test of the pituitary; the other, from 1997, treated growth hormone deficiency in children [2]. The maker discontinued both in 2008, and the approvals were withdrawn in 2009.
In 2013 the FDA determined that GEREF had not been withdrawn for reasons of safety or effectiveness [2]. That finding is what lets pharmacies compound sermorelin now, for adults and for uses the approval never covered.
What each has been tested in
| Tesamorelin | Sermorelin | |
|---|---|---|
| Largest controlled trials | 2 phase 3 trials, 806 adults with HIV, 26 weeks | None in adults |
| Adults without HIV | 60 adults with abdominal obesity, 12 months; 152 older adults, 20 weeks | 10 older men, 2 weeks; 11 older men, 6 weeks |
| Children | Not established, per the label | 110 children with growth hormone deficiency, open-label, 1 year |
| Placebo group in adult trials | Yes | No |
| FDA status | Approved 2010; a licensed biologic since 2020 | Approvals withdrawn 2009; not for safety |
| Can a pharmacy compound it? | No | Yes, under the 2013 determination |
Tesamorelin’s results
In the two phase 3 trials, 806 adults with HIV received 2 mg daily or placebo for 26 weeks [5]. Visceral fat fell with a treatment effect of −15.4%, and IGF-1 rose by a mean of 108 ng/mL. Glucose measures did not change in a clinically meaningful way.
Two trials went beyond HIV. In 60 adults with abdominal obesity and low growth hormone, 12 months of 2 mg daily cut visceral fat by 35 cm² more than placebo, with a 95% CI of −58 to −12 [6]. In 152 adults aged 55 to 87, 20 weeks of 1 mg nightly raised IGF-1 by 117% and lowered percent body fat by 7.4% [7].
Sermorelin’s results
The sermorelin record in adults rests on two studies of older men, neither with a placebo group running alongside it. In 10 men with a mean age of 68, 1 mg twice daily for 14 days raised 24-hour growth hormone and IGF-1 to the levels of young men; 0.5 mg twice daily did not [8].
In 11 men aged 64 to 76, 2 mg injected nightly for 6 weeks raised nighttime growth hormone but did not change IGF-1 [9]. Weight, muscle and fat measured by DEXA scan did not change either, and the authors concluded that a single nightly dose was less effective than several a day.
Sermorelin’s largest study is in children, the use GEREF was approved for. In 110 children with growth hormone deficiency, nightly injections raised mean height velocity from 4.1 to 8.0 cm a year after 6 months, in a trial with no control group [10].
How each was dosed
The tesamorelin trials used 2 mg once daily of the original formulation, and the current labels state 1.28 mg or 1.4 mg depending on the product [1]. The detail is in tesamorelin dosage.
Sermorelin’s only approved treatment regimen was for children, at 30 micrograms per kilogram under the skin at bedtime [3]. The adult studies above used 0.5 mg to 2 mg, once or twice a day, and none of those doses was ever approved. They are laid out in sermorelin dosage.
What the comparison means for a patient
If the question is which molecule has been tested more thoroughly, the answer is tesamorelin, by a wide margin, but only in people with HIV, obesity with low growth hormone, or memory complaints in later life. If the question is which one a pharmacy may lawfully compound, the answer is sermorelin, and only sermorelin.
None of the studies here measured sleep, and none tested either drug for building muscle in healthy younger adults, the use both are often sold for. For how sermorelin compares with a peptide that works on a different receptor, see sermorelin vs ipamorelin.