Skip to content
Peptigraph home

Ipamorelin vs MK-677: What the Research Shows

Ipamorelin and MK-677 side by side: what they are, how they are regulated and what is still unknown.

Medically reviewed by Juan Pablo Frías, MD · · DisclosureUpdated
GHRP (ghrelin receptor agonist)Not FDA approved · research chemicalIpamorelinGhrelin-receptor agonist peptide, not FDA-approved; in a randomized trial after bowel resection, median time to first tolerated meal was 25.3 versus 32.6 hours with placebo.[6]Growth hormone+70% searches
Oral ghrelin agonist (not a peptide)Not FDA approved · research chemicalMK-677Oral growth hormone secretagogue (not a peptide); in a randomized trial in obese men it raised IGF-I about 40% versus placebo.[9]
Quick verdict

Where the research points

Summary of studies, not a recommendation

Consider Ipamorelin if…

  • you want the option with a randomized human trial, though it found no significant difference from placebo (postoperative ileus): median time to first tolerated meal was 25.3 h vs 32.6 h[6]

Consider MK-677 if…

  • you want an oral option with randomized human data: in obese men, MK-677 25 mg daily raised serum IGF-I by about 40% versus placebo over 8 weeks (a hormone outcome)[9]
  • you are weighing trade-offs: in that trial an oral glucose tolerance test showed impairment of glucose homeostasis at 2 and 8 weeks[9]
  • you want to see a negative human trial: in Alzheimer disease, MK-677 raised serum IGF-1 but was ineffective at slowing disease progression[10]

What they have in common

  • WADA prohibits growth hormone secretagogues at all times; its list names ibutamoren (MK-677) and ipamorelin[2]
Ipamorelin is prohibited in tested sport (WADA). Status labels come from public FDA and WADA records; see the sources below.
Side by side

Spec comparison

Showing 9 of 11 fields where the two differ. FDA status, PCAC vote, Jul 2026 are the same or both unknown.

FieldIpamorelinMK-677
ClassGHRP (ghrelin receptor agonist)Oral ghrelin agonist (not a peptide)
Also calledipa, ipamibutamoren
WADAProhibited by WADA (S2.2.4)Ipamorelin is named as a growth hormone secretagogue in S2.2.4, prohibited at all times.No WADA record in our data
Anti-doping detection
  • After nasal dosing, ipamorelin metabolites were still found in urine after the parent drug was gone (samples were collected for 2 days).PMID 25869809
  • A direct-urine screen includes ipamorelin among the peptides it can detect, at 50 to 500 pg/mL.PMID 26578461
None reportedanti-doping literature, as of 2 Oct 2026
Half-life2 hours terminal half-lifeintravenous infusion (15 min) · Pharmaceutical research 1999, PMID 10496658[half-life by route]
Evidence strengthHuman RCT evidence, 4 of 4Strongest: International journal of colorectal disease 2014, PMID 25331030[evidence grade]
Human studies we summarised2 human (2 randomized or controlled) of 12 summarised[n]
Typical study doses[dose range]
Named in FDA warning letters, 2026Yes (24 Aug 2026)Not in the letters we track

Bracketed values are pending a sourced figure. Legal data reflects the regulatory events in our tracker.

Sources

  1. 1FDA warning letters to five research-peptide sellersFDA warning letter (NuScience Peptides; 1 of 5) · 2026fda.govAccessed 2 Oct 2026
  2. 2World Anti-Doping Code International Standard Prohibited List 2026World Anti-Doping Agency · 2026wada-ama.orgAccessed 2 Oct 2026
  3. 3Determination of growth hormone releasing peptides metabolites in human urine after nasal administration of GHRP-1, GHRP-2, GHRP-6, Hexarelin, and Ipamorelin.Drug testing and analysis · 2015PMID 25869809Accessed 2 Oct 2026
  4. 4Simplifying and expanding the screening for peptides <2 kDa by direct urine injection, liquid chromatography, and ion mobility mass spectrometry.Journal of separation science · 2016PMID 26578461Accessed 2 Oct 2026
  5. 5Pharmacokinetic-pharmacodynamic modeling of ipamorelin, a growth hormone releasing peptide, in human volunteers.Pharmaceutical research · 1999PMID 10496658Accessed 2 Oct 2026
  6. 6Prospective, randomized, controlled, proof-of-concept study of the Ghrelin mimetic ipamorelin for the management of postoperative ileus in bowel resection patients.International journal of colorectal disease · 2014PMID 25331030Accessed 2 Oct 2026
  7. 7The growth hormone secretagogue receptor 1a agonists, anamorelin and ipamorelin, inhibit cisplatin-induced weight loss in ferrets: Anamorelin also exhibits anti-emetic effects via a central mechanism.Physiology & behavior · 2024PMID 39043357Accessed 2 Oct 2026
  8. 8PubMed search: (ipamorelin[tiab]) AND (ibutamoren[tiab] OR "MK-677"[tiab] OR MK0677[tiab])PubMed · 2026pubmed.ncbi.nlm.nih.govAccessed 2 Oct 2026
  9. 9Two-month treatment of obese subjects with the oral growth hormone (GH) secretagogue MK-677 increases GH secretion, fat-free mass, and energy expenditure.The Journal of clinical endocrinology and metabolism · 1998PMID 9467542Accessed 2 Oct 2026
  10. 10Growth hormone secretagogue MK-677: no clinical effect on AD progression in a randomized trial.Neurology · 2008PMID 19015485Accessed 2 Oct 2026

Found an error? Report a correction.