Tesamorelin and sermorelin both copy GHRH, the hormone that tells the pituitary to release growth hormone. Sermorelin is the first 29 amino acids of GHRH. Tesamorelin is the full 44-amino-acid GHRH with a trans-3-hexenoyl group added at one end, which slows its breakdown. Tesamorelin is FDA-approved as Egrifta for excess abdominal fat in HIV. Sermorelin was approved as Geref, but its approvals were withdrawn effective 18 June 2009 after the maker stopped selling it, and FDA later found the exit was not for safety or effectiveness reasons.
How do tesamorelin and sermorelin differ?
Tesamorelin is the longer, stabilised molecule with an FDA approval. Sermorelin is the shorter fragment whose approval lapsed.
| Sermorelin | Tesamorelin | |
|---|---|---|
| Structure | GHRH 1-29, unmodified | Full GHRH 1-44 plus an N-terminal trans-3-hexenoyl group |
| Half-life | About 12 minutes | 26 to 38 minutes (Egrifta label) |
| FDA status | Approvals withdrawn 2009 (discontinued 2008) | Approved as Egrifta |
| Approved indication | Pediatric GH deficiency and a pituitary diagnostic test (former) | Excess abdominal fat in HIV-associated lipodystrophy |
| Withdrawal reason | Commercial, not safety | n/a |
| 503A compounding | Yes | No; a licensed biologic since 23 March 2020 |
| Best evidence | Pediatric GH deficiency | Visceral fat in HIV |
Both bind the GHRH receptor on the pituitary and trigger the body's own GH release in pulses. The added group on tesamorelin resists breakdown by the enzyme DPP-4, so each injection keeps the receptor engaged longer.
Is sermorelin still FDA-approved?
No. EMD Serono discontinued Geref in 2008; for the diagnostic version it said the active ingredient was no longer being manufactured. FDA withdrew both approvals effective 18 June 2009 (74 FR 23407) and in 2013 determined they were not withdrawn for safety or effectiveness reasons (78 FR 14095). Tesamorelin is now the only GHRH analog with a current US approval. The full timeline is on our sermorelin page.
What does the clinical evidence show?
Tesamorelin has the strongest body-composition data of any GHRH analog. In the Falutz trial and the Egrifta pivotal program in HIV-associated lipodystrophy, visceral fat measured by CT fell about 15-18% over 26 weeks. The fat came back after people stopped. IGF-1 rose but stayed within reference ranges in most patients.
Sermorelin evidence comes mostly from children with GH deficiency, the use FDA approved. The adult studies are small and short, and one six-week study in older men found no change in IGF-1 or body composition. Our sermorelin page lists each study and the protocols it used. These are records of what trials did, not dosing advice.
How much do they cost?
| Product | Cost |
|---|---|
| Egrifta WR (branded tesamorelin) | About $10,709 per kit, cash (Drugs.com, 10 Oct 2026) |
| Compounded tesamorelin | Not lawful under 503A: FDA lists Egrifta among products deemed biologics licenses on 23 March 2020 |
| Compounded sermorelin (503A) | Varies by pharmacy; we have no sourced figure |
| Research-grade vials, either | Lower; sold for laboratory use only |
What side effects do they share?
Both act on the GH axis, so the reported effects overlap: fluid retention, joint pain, tingling, lower insulin sensitivity with long use, and higher IGF-1, which raises a theoretical concern for people with existing tumours. The Egrifta trials reported injection-site reactions, joint pain, peripheral swelling and mild changes in glucose tolerance.
What this comparison does not settle
- Long-term effects. Published trials run 6 to 12 months at most. No one has measured effects on healthspan or lifespan.
- Use in healthy adults. The Egrifta label covers HIV-associated lipodystrophy only. No trial has tested either drug in healthy adults for body composition.
- Stacks. GHRH analogs are often paired with ghrelin-receptor agonists such as ipamorelin; see CJC-1295 vs ipamorelin.
Related reading
- Sermorelin: FDA history, compounding status and lab results.
- Tesamorelin: the FDA-approved GHRH analog.
- Tesamorelin vs HGH: releasing your own GH against injecting it.
- CJC-1295 vs ipamorelin: the most-paired GH-axis stack.
- Longevity peptides 2026: where the GH-axis cluster sits.
Sources
- Falutz J et al. Metabolic effects of a growth hormone-releasing factor in patients with HIV. N Engl J Med 2007
- Stanley TL et al. Reduction in visceral adiposity is associated with an improved metabolic profile in HIV-infected patients receiving tesamorelin. AIDS 2014.
- Walker RF. Sermorelin: a better approach to management of adult-onset growth hormone insufficiency? Clin Interv Aging 2006
- FDA, Egrifta (tesamorelin) label, 2010
- Federal Register, Geref withdrawal, 19 May 2009 and determination, 4 March 2013
Frequently asked
What's the main difference between tesamorelin and sermorelin?
Sermorelin is the first 29 amino acids of GHRH and clears in about 12 minutes. Tesamorelin is the full 44-amino-acid GHRH with an added chemical group that resists breakdown, giving a half-life of 26 to 38 minutes on the Egrifta label. Tesamorelin is FDA-approved; sermorelin's approvals were withdrawn in 2009, not for safety reasons.
Which one is FDA-approved?
Tesamorelin, as Egrifta, for excess abdominal fat in HIV-associated lipodystrophy. Sermorelin was approved as Geref in 1990 (a diagnostic test) and 1997 (pediatric GH deficiency). EMD Serono discontinued it in 2008, FDA withdrew the approvals effective 18 June 2009, and in 2013 FDA found the exit was not for safety reasons.
Which one is better for body composition?
Only tesamorelin has trial evidence and an FDA-approved indication for body fat. In the Egrifta trials in HIV-associated lipodystrophy, visceral fat fell about 15-18% over 26 weeks. Sermorelin has no comparable body-composition trial; a six-week study in older men found no change in body composition.
What's the cost difference?
Egrifta WR, the current branded tesamorelin, was listed at about $10,709 per kit cash on Drugs.com on 10 October 2026. Tesamorelin has been regulated as a biologic since March 2020, so 503A pharmacies cannot compound it. Compounded sermorelin prices vary by pharmacy and we have no sourced figure. Research-peptide vendors charge less for both, but those vials are sold for laboratory research only and are not for human use.
Are tesamorelin and sermorelin safe to combine?
No study has tested them together. Both act on the same receptor, the GHRH receptor, so a second GHRH analog adds little in principle. The combination people more often discuss pairs one GHRH analog with a ghrelin-receptor agonist such as ipamorelin, which acts on a different receptor. Neither pairing has trial data.