Sermorelin and tesamorelin are growth hormone releasing hormone analogs with an approved-drug history, and research vendors sell both. People searching for one often land on the other. We read the drug label, the Federal Register, the trial abstracts and the vendor listings to set out what separates them. This is not advice to use either one, and vendors label both for laboratory research only.
What separates them
Sermorelin is the first 29 amino acids of human growth hormone releasing hormone, with an amidated end, at about 3,358 Da on the Peptryn listing. Tesamorelin keeps all 44 amino acids and adds a trans-3-hexenoyl group at the start, at about 5,136 Da. Peptides for Sale says that group makes tesamorelin more resistant to breakdown. Both act on the same receptor, and the tesamorelin label says it stimulates the release of the body's own growth hormone.
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| Sermorelin | Tesamorelin | |
|---|---|---|
| Structure | 29 amino acids of GHRH | All 44 amino acids of GHRH plus an N-terminal group |
| Mass and CAS on the Peptryn listing | 3,357.93 Da, 86168-78-7 | 5,135.88 Da, 218949-48-5 |
| Approved-drug history | Geref was an FDA-approved injection. A 2013 FDA notice found it was not withdrawn for safety or effectiveness reasons. We found no current sermorelin label. | Egrifta WR is indicated for excess abdominal fat in HIV-infected adults with lipodystrophy. The label says it is not for weight loss management. |
| Human trials we found | Two 1993 trials in children with growth hormone deficiency | Pooled phase 3 trials in 806 adults with HIV |
| What was measured | Growth in height, hormone levels, antibodies | Visceral fat by CT scan, lipids, IGF-I, safety |
| Named on the 2026 WADA list, per the Cologne laboratory | Yes, among GHRH analogs | Yes, among GHRH analogs |
What sermorelin trials showed
The sermorelin trials we found were in children. In a 1993 trial of 60 children with growth hormone deficiency, height velocity was 9.2 and 9.3 cm a year on the two GHRH(1-29) regimens against 14.6 cm a year on growth hormone itself. IGF-I rose at first and then fell back to its starting range. Nearly every child on GHRH(1-29) developed antibodies to it, 39 of 40, and the antibodies had almost gone nine months after stopping. The authors concluded it was unlikely to be as effective as growth hormone for growth. A 1997 trial of a close analog in 19 older adults reported more lean body mass in men only, which our post on the best peptides for muscle growth covers.
What tesamorelin trials showed
A pooled analysis of two phase 3 trials randomized 806 adults with HIV and excess abdominal fat. At 26 weeks, visceral fat measured by CT fell 15.4% more on tesamorelin than on placebo, with no significant change in subcutaneous abdominal fat. IGF-I rose, and the abdominal changes did not last: in an extension study, visceral fat reaccumulated after the drug was stopped. The label lists neoplasms, raised IGF-1, fluid retention, glucose intolerance and hypersensitivity among its warnings, and contraindicates it in active malignancy and pregnancy.
Which one has muscle data
Neither, in the trials we found. The tesamorelin trials measured fat and lipids, and the sermorelin trials measured growth in children. The one lean mass result is the 1997 analog trial in 19 people. Our post on what trials measured for muscle gain sets this against the other published studies.
What the vendors list
All four vendors we review list both compounds (, and for American Peptides), and the paperwork differs.
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| Vendor | Sermorelin listing | Tesamorelin listing |
|---|---|---|
| Peptryn | 10 mg, lot 2026-08-05, 99.65% by HPLC-UV-MS, endotoxin negative, tested by MZ Biolabs | 10 mg, lot 2026-08-05, 99.97% by HPLC-UV-MS, endotoxin negative, MZ Biolabs. The 20 mg report is sent on request. |
| American Peptides | 5 mg, one certificate in its library (lot SERMO5-0318). We did not read it. | 10 mg and 20 mg, one certificate each (lots TESA10-0803 and TESA20-0803). We did not read them. |
| Core Power Peptides | 5 mg page says a COA is provided with every batch | 10 mg page says a COA is available on request. It was out of stock when we read it. |
| Peptides for Sale | No COA statement on the page we read | Page says a COA is available for each batch |
Peptryn's tesamorelin page notes that the approved Egrifta product is a different product from its research vial. That is worth keeping in mind with any vial: a label for the drug does not describe a research material. Our guide to reading a COA explains what each line proves, and the reviews of Peptryn, Core Power Peptides and Peptides for Sale list what we could not confirm for each.
Sports and compounding status
The Cologne anti-doping laboratory's page on the 2026 WADA Prohibited List names both sermorelin and tesamorelin among the growth hormone releasing hormone analogs. The FDA's page on bulk substances that may pose significant safety risks, current as of 22 April 2026, does not mention either one. That absence is not an approval of either compound for compounding.
Frequently asked questions
What is the difference between sermorelin and tesamorelin?
Sermorelin is the first 29 amino acids of growth hormone releasing hormone. Tesamorelin is all 44 amino acids with an added chemical group at one end. Both act on the same receptor.
Is tesamorelin FDA approved?
The brand Egrifta WR is, for excess abdominal fat in HIV-infected adults with lipodystrophy. A research vial is a different product from the drug. Check the current label before relying on this.
Is sermorelin FDA approved?
Geref was approved in the past, and a 2013 FDA notice says it was not withdrawn for safety or effectiveness reasons. We found no current sermorelin label on DailyMed. Check FDA records.