Ipamorelin vs MK-677
An injectable selective peptide against an oral small molecule. MK-677 has by far the deeper trial record, and that record is largely what argues against it.
Ipamorelin
Raises GH, but failed its one rigorous human efficacy RCT; no body-composition outcome data.
Full Ipamorelin evidence reviewMK-677
Ibutamoren
An oral ghrelin mimetic that reliably lifts GH, IGF-1 and lean mass — but the same trials found no gain in strength or function, plus metabolic and cardiac safety signals.
Full MK-677 evidence reviewSide by side
| Ipamorelin | MK-677 | |
|---|---|---|
| Marketed for | Muscle, fat loss, 'anti-aging' | Muscle, sleep, 'anti-aging' |
| Evidence grade | Clinical data | Clinical data |
| Family | GH axis | GH axis |
| Regulatory status | Not FDA-approved | Not FDA-approved |
| How it's obtained | Research-only | Research-only |
| Key human source | Beck RCT, 2014 | Nass, Ann Intern Med 2008 |
marks a row where the two differ. Evidence grades come from our evidence matrix, which grades each molecule on the human data for the use it is marketed for.
Our verdict
MK-677 is not a peptide; it is an orally active ghrelin mimetic with the deepest human evidence base in this group. It reliably raises GH and IGF-1, and in a two-year randomized trial in healthy older adults it increased fat-free mass by 1.1 kg versus a 0.5 kg loss on placebo, yet the authors reported that gain did not result in changes in strength or function. It also raises fasting glucose, reduces insulin sensitivity, and a hip-fracture trial was terminated early for a heart-failure safety signal. Ipamorelin has a cleaner hormonal profile on paper but a much thinner record, and its one rigorous randomized human efficacy trial failed its primary endpoint. Neither is FDA-approved, both are sold as research chemicals, and they have not been compared directly.
Ipamorelin fits if
Ipamorelin is the one to read about if selectivity is your question, meaning a GH pulse with minimal cortisol, prolactin or appetite effect.
MK-677 fits if
MK-677 is the more instructive case if you want to see what happens when a GH secretagogue is actually taken to outcome trials; the biomarkers moved and the outcomes did not.
Where to get it
Where to get peptide therapy
Clinician-led telehealth services that prescribe compounded peptides. The specific peptides offered vary by provider — confirm CJC-1295 & Ipamorelin availability before ordering.
