Research use only. Nothing on this page is medical advice, and neither peptide is approved for body composition, anti-aging or performance.
Ipamorelin and sermorelin both raise growth hormone (GH), but they use different receptors:
- Sermorelin copies the first 29 amino acids of GHRH and works through the GHRH receptor
- Ipamorelin mimics ghrelin at the GHS-R1a receptor (1, 2)
No trial has compared them in people, and neither is FDA-approved today.
Jump to the comparison, the evidence, safety or where to buy.
Ipamorelin vs sermorelin at a glance
| Feature | Ipamorelin | Sermorelin |
|---|---|---|
| 1What it is | A five-amino-acid peptide, Aib-His-D-2Nal-D-Phe-Lys-NH2, that stimulates GH release (3) | A 29-amino-acid GHRH analog, also called GRF 1-29 (2) |
| 2Receptor | GHS-R1a, the ghrelin receptor (1) | The GHRH receptor on pituitary somatotrophs (1) |
| 3How long it lasts | Terminal half-life of about 2 hours in healthy men (4) | About 10 minutes in rats. We found no human figure (5) |
| 4Cortisol and ACTH | Not raised in swine, even above 200 times the ED50 (3) | Not a reported feature of GHRH analogs in the pediatric record (2) |
| 5Human trials | Healthy volunteers, plus a phase II ileus trial that missed its endpoint (4, 6) | Children with GH deficiency, diagnosis and treatment, mostly small (2) |
| 6US approval | None | Geref was approved. The approvals were withdrawn on 18 June 2009 (1) |
| 7FDA compounding page | Category 2 under the 503B interim policy (7) | Not listed on that page (7) |
| 8WADA 2026 | Named and prohibited, S2.2.4 (8) | Named and prohibited, S2.2.4 (8) |
How does each one work?
Your pituitary releases GH in pulses. GHRH tells it to release, and somatostatin tells it to stop. Sermorelin sits on the GHRH side, so somatostatin keeps its role (1).
Ipamorelin goes through the ghrelin receptor. In the 1998 study it released GH about as well as GHRP-6. But GHRP-6 and GHRP-2 also raised ACTH and cortisol in swine, and ipamorelin did not, even at more than 200 times its ED50 (3). That selectivity is why people got interested. It is animal data, so don’t read it as proof for people.
What does the evidence show?
Nine sources, sorted by closeness to humans. None of them compares the two peptides.
How to read the table. Failed: a human trial that missed its endpoint. Limited: small human data. Rats, Mice, Swine: animal work only. Review: a summary of other studies.
| Study | Model | What it reported | Watch-out |
|---|---|---|---|
| People | |||
| 1Beck, 2014Phase II, double-blind, placebo-controlled | 117 adults after bowel resection, ipamorelin by IV | FailedMedian time to the first tolerated meal was 25.3 hours on ipamorelin and 32.6 on placebo (P = .15). Adverse events: 87.5% against 94.8% (6) | A gut-motility endpoint, not GH. FDA cites an IV gastric-motility study with serious adverse events including death (7) |
| 2Gobburu, 1999Dose-escalation study | Healthy men, eight per dose level, IV ipamorelin | LimitedGH peaked at 0.67 hours and fell to negligible levels. Terminal half-life was 2 hours (4) | Short infusions. No efficacy endpoint |
| 3Prakash, 1999Review of sermorelin trials | Children with idiopathic GH deficiency | LimitedA single IV dose worked as a diagnostic test. Daily injections raised height velocity in some prepubertal children, less than somatropin did (2) | Small pediatric studies. Effect on final adult height unknown |
| 4Vasylieva, 2026Systematic review, 76 studies | Peptides in sexual medicine | ReviewGH secretagogues reliably raise GH and IGF-1, but evidence for sexual function, physical performance or quality of life is limited (9) | Covers a whole class, not these two alone |
| Animals | |||
| 5Raun, 1998Cell and animal pharmacology | Rat pituitary cells, rats, swine | SwineGH release matched GHRP-6 in rat cells (EC50 1.3 against 2.2 nmol/L). Swine ED50 was 2.3 nmol/kg. No ACTH or cortisol rise at over 200 times the ED50 (3) | No human cortisol data in this paper |
| 6Johansen, 1999Controlled rat study, 15 days | Adult female rats | RatsBone growth rose from 42 to 52 micrometres a day with dose. The GH response to a later ipamorelin challenge was marginally reduced, while the GHRH response was unchanged (10) | That small loss of response is why “never desensitizes” is too strong |
| 7Estrada, 2002Controlled rat study, 21 days | Young female rats, cultured pituitary cells | RatsCells from GHRH-treated rats stopped responding to new stimulation. Cells from ipamorelin-treated rats kept responding (11) | A culture readout after treatment, in one species |
| 8Lall, 2001Controlled mouse study | GH-deficient and GH-intact mice | MiceIpamorelin raised body fat, serum leptin and food intake without GH (12) | Fat gain is the opposite of what most buyers want |
| 9Rafferty, 1985Pharmacokinetics in rats | Anesthetized rats, hGRF 1-29-NH2 by IV and SC | RatsElimination half-life was 10.4 minutes. After SC injection only 4% reached the circulation compared with IV (5) | Old rat data, not human sermorelin kinetics |
The pattern is simple. Ipamorelin has a short human kinetics record and one failed phase II trial. Sermorelin has a longer record, but in children with GH deficiency, and that product is gone. Neither is approved for body composition or performance, and reviews rate the evidence for those uses as limited (1, 9).
Which one desensitizes the pituitary?
A popular claim says GHRH analogs like sermorelin blunt the pituitary over time while ipamorelin doesn’t. The support is thin. In young rats, 21 days of GHRH left cultured pituitary cells unresponsive to new stimulation, and ipamorelin didn’t (11). In adult rats, 15 days of ipamorelin slightly reduced the next response to ipamorelin (10). Both studies used rats, and no human data exist.
Can you combine ipamorelin and sermorelin?
Forums stack ipamorelin with a GHRH analog on the idea that the two add up. A 2026 review calls that practice anecdotal and says controlled evidence of synergy is limited (1). If a stack seems to work, you can’t tell which part did it. Our CJC-1295 and ipamorelin guide covers the most common pairing.
Ipamorelin vs sermorelin side effects and safety
- Sermorelin’s pediatric record lists transient facial flushing and injection-site pain (2).
- Ipamorelin’s phase II trial reported similar adverse-event rates on drug and placebo and called the drug well tolerated (6). FDA’s page still cites immunogenicity risk, unnatural amino acids and a gastric-motility study with serious adverse events including death (7).
- In mice, ipamorelin raised body fat and food intake without GH (12).
- Both raise GH and IGF-1. Reviews call the growth-signal worry theoretical, with no clinical cancer signal and no long-term data (1).
More detail is in our ipamorelin side effects guide.
Ipamorelin and sermorelin dosage: is there one?
We don’t list doses. No approved dose exists for ipamorelin, and sermorelin’s documented doses come from a withdrawn pediatric product. The dose tables on forums are self-reports. The 2026 review that collected them calls them behavioral data and says they carry no clinical recommendation (1).
Are ipamorelin and sermorelin legal?
No sermorelin product is FDA-approved today. Geref was, until the maker stopped selling it and the approvals were withdrawn on 18 June 2009. FDA later said that wasn’t for safety or effectiveness reasons (1). Ipamorelin was never approved.
FDA’s compounding-risk page lists ipamorelin acetate in Category 2 under the 503B interim policy, added 29 September 2023, and doesn’t list sermorelin (7). The HHS enforcement policy of 28 October 2026 names six other peptides and neither of these (13). WADA’s 2026 list names both, so tested athletes can’t use either (8).
A research-use-only label is a sales category. It tells you nothing about what is in the vial.
Where to buy ipamorelin and sermorelin
Three sellers list both peptides. Their lot reports differ a lot, so read the table before the price. Vial sizes differ too, so compare price per mg and not the headline price.
| Seller | Ipamorelin | Sermorelin | Watch-out |
|---|---|---|---|
| 1Amino Club | 10 mg, $49.99. ILS Laboratories, lot IPA0002, tested 30 Jul 2026. Purity 99.79% by HPLC, 10.4 mg measured (14) | 10 mg, $59.99. ILS Laboratories, lot SER0002, tested 22 Oct 2026. Purity 99.41% by HPLC, 10.43 mg measured (15) | Identity is an HPLC match, with no mass spectrum |
| 2Elite Edge | 10 mg, $45. Certificate on request. The CJC-1295 blend has an MZ Biolabs report at 99.78% (16, 17) | 10 mg, $49. MZ Biolabs, lot 2026-07-22. Purity 99.64%, measured mass 3355.92 Da against 3355.82 expected (18, 19) | The sermorelin report gives no content in mg |
| 3SwissChems | 2 mg, $21.95. Six lot reports linked. Two Freedom Diagnostics reports show 99.96% (2.17 mg) and 99.88% (2.13 mg) with LC-MS identity (20, 21) | 2 mg, $25.95. The only report linked is titled heavy metal. No purity or content report (22) | The client on the Freedom reports is IMT, not SwissChems |
Amino Club
Ipamorelin 10 mg · $49.99 ($5.00 per mg) · Sermorelin 10 mg · $59.99 ($6.00 per mg)
- Lot reports on both product pages from ILS Laboratories (ISO/IEC 17025)
- Each report lists purity, measured content, heavy metals and sterility results
- Free standard shipping over $100, same-day dispatch before 3 PM ET
Elite Edge Biotech
Ipamorelin 10 mg · $45 ($4.50 per mg) · Sermorelin 10 mg · $49 ($4.90 per mg)
- Sermorelin certificate from MZ Biolabs with mass spectrometry identity
- Ipamorelin certificate sent on request
- Free US shipping over $200
SwissChems
Ipamorelin 2 mg · $21.95 ($10.98 per mg) · Sermorelin 2 mg · $25.95 ($12.98 per mg)
- Six ipamorelin lot reports linked on the product page
- Same-day US shipping before 12 PM EST
- 30-day returns on unopened products
Match the lot number on your vial to a report before you trust it. Our guide to verifying a peptide COA shows how. For sermorelin alone, see sermorelin peptide for sale and our GHRH peptides guide. More sellers are in best peptide vendors.
Ipamorelin vs sermorelin FAQ
What is the difference between ipamorelin and sermorelin?
Sermorelin is a 29-amino-acid GHRH analog that works through the GHRH receptor. Ipamorelin is a five-amino-acid peptide that works through the ghrelin (GHS-R1a) receptor. Both raise growth hormone. They differ in target, half-life and regulatory history, and no trial has compared them.
Which is better, ipamorelin or sermorelin?
Nobody can say. No head-to-head trial exists, and neither has a trial in healthy adults showing a body-composition or anti-aging benefit. Compare them on regulatory history and lot reports, and ask a clinician before using either.
Is sermorelin FDA approved?
Not today. FDA approved it as Geref, but the approvals were withdrawn on 18 June 2009 after the maker stopped selling it. FDA later said the withdrawal wasn’t for safety or effectiveness reasons.
Is ipamorelin FDA approved?
No. Ipamorelin has never been approved. FDA lists ipamorelin acetate in Category 2 under its 503B interim compounding policy and cites immunogenicity risk and an intravenous study with serious adverse events.
What is the ipamorelin or sermorelin dosage?
No approved dose exists for ipamorelin, and sermorelin’s documented doses come from a withdrawn pediatric product. We don’t list doses. Forum tables are self-reports that carry no clinical recommendation.
What are the side effects of ipamorelin and sermorelin?
Sermorelin’s pediatric record lists flushing and injection-site pain. Ipamorelin’s phase II trial reported similar adverse-event rates to placebo. Neither has long-term safety data, and gray-market product quality varies.
Are ipamorelin and sermorelin banned in sport?
Yes. WADA’s 2026 Prohibited List names both under S2.2.4, growth hormone releasing factors and secretagogues.
Sources
Show references (22)Hide references
- Dominikowski A, et al. The emerging landscape of performance-enhancing peptides modulating GH-IGF1 axis. Front Endocrinol 2026. Source
- Prakash A, Goa KL. Sermorelin: a review of its use in the diagnosis and treatment of children with idiopathic growth hormone deficiency. BioDrugs 1999. Source
- Raun K, et al. Ipamorelin, the first selective growth hormone secretagogue. Eur J Endocrinol 1998. Source
- Gobburu JV, et al. Pharmacokinetic-pharmacodynamic modeling of ipamorelin, a growth hormone releasing peptide, in human volunteers. Pharm Res 1999. Source
- Rafferty B, et al. Growth hormone-releasing factor analogue (hGRF1-29NH2): immunoreactive-GRF plasma levels after intravenous and subcutaneous administration. J Endocrinol 1985. Source
- Beck DE, et al. Prospective, randomized, controlled, proof-of-concept study of the ghrelin mimetic ipamorelin for the management of postoperative ileus in bowel resection patients. Int J Colorectal Dis 2014. Source
- FDA. Certain bulk drug substances for use in compounding that may present significant safety risks (content dated 22 April 2026). Source
- WADA. The 2026 Prohibited List, section S2.2.4. Source
- Vasylieva V, et al. Peptides in urology and sexual medicine: clinical effectiveness, dosing, indications, and safety. Sex Med Rev 2026. Source
- Johansen PB, et al. Ipamorelin, a new growth-hormone-releasing peptide, induces longitudinal bone growth in rats. Growth Horm IGF Res 1999. Source
- Estrada RC, et al. Chronic in vivo ipamorelin treatment stimulates body weight gain and growth hormone release in vitro in young female rats. Eur J Anat 2002. Source
- Lall S, et al. Growth hormone (GH)-independent stimulation of adiposity by GH secretagogues. Biochem Biophys Res Commun 2001. Source
- BakerHostetler. HHS issues enforcement discretion policy regarding 503A compounding using certain peptide bulk drug substances. 28 October 2026. Source
- Amino Club. Ipamorelin 10 mg product page with the released lot report (ILS Laboratories, lot IPA0002). Source
- Amino Club. Sermorelin 10 mg product page with the released lot report (ILS Laboratories, lot SER0002). Source
- Elite Edge Biotech. Ipamorelin 10mg product page. Source
- MZ Biolabs certificate for Elite Edge, ipamorelin with CJC-1295 no DAC, lot 2026-05-28. Source
- Elite Edge Biotech. Sermorelin 10mg product page. Source
- MZ Biolabs certificate for Elite Edge, sermorelin 10 mg, lot 2026-07-22. Source
- SwissChems. Ipamorelin 2mg product page and linked lot reports. Source
- Freedom Diagnostics report linked from SwissChems, ipamorelin lot 2608-CY-IP. Source
- SwissChems. Sermorelin 2mg product page and linked report. Source