Verified July 2026 · Cited to primary sources

Ipamorelin: Evidence Grade C. Early / foreign human data only.

Grade CResearch-onlySafety: amber

The honest verdict

The most selective GHRP on paper and the best-tolerated in a real human trial, but that trial failed and there is no human evidence it does the muscle or fat-loss job it is sold for. Interesting pharmacology, unproven benefit, not legal to compound.

Ipamorelin at a glance

Class
Growth hormone secretagogue (selective ghrelin/GHS-R1a agonist, pentapeptide)
Mechanism
Binds the ghrelin receptor (GHS-R1a) on pituitary somatotroph cells and triggers a pulse of stored growth hormone. Its selling point is selectivity: at GH-releasing doses it does not meaningfully raise ACTH, cortisol, prolactin, FSH, LH or TSH, which is what separates it from GHRP-6 and GHRP-2. It still needs your own GHRH axis to work, so it is not a substitute for GH itself.
Also known as
NNC 26-0161
Research applications
  • Postoperative ileus / gastric motility (Phase 2, failed)
  • Growth hormone stimulation research
  • Preclinical bone and body-composition models
Forms
Lyophilized powder for reconstitution (research supply), Subcutaneous injection (research use)
Legal status
Research-only
WADA (anti-doping)
Prohibited at all times (S2.2.4, growth hormone secretagogues), named on the WADA Prohibited List
Evidence grade
Grade CEarly / foreign human data only

How we grade evidence

Every grade comes from a fixed A to F rubric: human-trial strength, not hype or affiliate status. Last verified July 6, 2026.

What is Ipamorelin?

The cleanest of the GH-releasing peptides on paper: it bumps GH without the cortisol and prolactin spike the older GHRPs cause. But the honest headline is that the one real human trial was for gut motility, not muscle, and it flat-out failed. Zero human data proving it builds muscle or burns fat.

Binds the ghrelin receptor (GHS-R1a) on pituitary somatotroph cells and triggers a pulse of stored growth hormone. Its selling point is selectivity: at GH-releasing doses it does not meaningfully raise ACTH, cortisol, prolactin, FSH, LH or TSH, which is what separates it from GHRP-6 and GHRP-2. It still needs your own GHRH axis to work, so it is not a substitute for GH itself.

How strong is the evidence for Ipamorelin?

One genuine human Phase 2 randomized controlled trial exists (Beck 2014, 114 bowel-resection patients) but it missed every primary and secondary endpoint and the program was discontinued. That failure was in gut motility, not in muscle growth, so it does not brand ipamorelin a failure for the reason people actually buy it. But there is also zero human efficacy trial showing it builds lean mass, aids recovery or burns fat. So: real human exposure and a good safety/selectivity signal, no proof of the marketed benefit. That is a C, not higher.

Primary sources (3)

  1. Raun 1998, Eur J Endocrinol, 'Ipamorelin, the first selective growth hormone secretagogue' (defines its selectivity; no ACTH/cortisol rise vs GHRP-6/2)
  2. Beck 2014, Int J Colorectal Dis, Phase 2 RCT for postoperative ileus; well tolerated but no significant benefit vs placebo on any endpoint
  3. WADA Prohibited List, growth hormone secretagogues (incl. ipamorelin) banned at all times (S2.2.4)

What is Ipamorelin used for?

Ipamorelin is marketed for the goals below. See how it ranks against other peptides in each, by evidence, not hype.

Best peptides for Muscle Growth →

What does Ipamorelin cost, and how do you access it legally?

Typical cost

UNKNOWN

No legitimate FDA-approved or compounded route to price, so any number would be a gray-market figure. Sold only as a research chemical. We do not price research chemicals.

No legal supervised access route right now.

Ipamorelin has no compliant US route today. Vials sold "for research use only" are a gray-market fig-leaf, not a legal loophole, so we don't link them. If you pursue Ipamorelin, do it with a licensed clinician, and re-check its legal status first.

Is Ipamorelinsafe? Side effects & risks

Limited human safety data, no major documented harms

Not an FDA-approved drug and cannot be legally compounded; PCAC voted against 503A inclusion in October 2024. The Phase 2 trial showed it was well tolerated at 0.03 mg/kg twice daily, which is the best human safety signal in this whole class, but that is short-term GI-patient data, not long-term healthy-user data. Chronic GH elevation carries the class risks: water retention, joint aches, carpal-tunnel-type symptoms, and a theoretical concern about anything that raises IGF-1 long term. Biggest real-world risk is the supply chain: FDA testing found roughly 40% of online/compounded peptides had wrong doses or undeclared ingredients.

Medical disclaimer: This page is independent editorial information, not medical advice, and Best Peptide For That is not a medical provider. We do not provide dosing. Talk to a licensed clinician before starting, stopping, or changing any peptide or medication. Full medical disclaimer.

FAQ

Ipamorelin FAQ

Is ipamorelin FDA-approved?

No. It reached Phase 2 for postoperative ileus, failed, and was discontinued. It is sold only as a research chemical and cannot be legally compounded. PCAC voted against including it in 503A compounding in October 2024.

Does ipamorelin build muscle?

There is no human trial showing it builds muscle. It reliably raises growth hormone in the short term, but no controlled study has measured lean mass, strength or fat loss in people using it. That gap is the whole reason it grades C.

Why is ipamorelin considered 'cleaner' than GHRP-6?

Because at GH-releasing doses it does not spike cortisol, ACTH or prolactin the way GHRP-6 and GHRP-2 do. That selectivity is well documented (Raun 1998). It means fewer off-target hormone effects, not that it works better for muscle.

Is ipamorelin banned in sport?

Yes. All growth hormone secretagogues are prohibited at all times under WADA section S2.2.4. Ipamorelin is named on the list.

From our portfolio

Tracking Ipamorelin?

Titrate is an iOS app for logging doses, schedules and progress over time, with a reconstitution calculator built in. It tracks, it does not prescribe.

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Grade C

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Grade B

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How we grade the evidence →Are peptides safe? →FDA peptide status 2026 →

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