Peptide Comparison
Ipamorelin vs MK-677
Editorial breakdown of mechanism, evidence, decision criteria, and the misconceptions worth calling out.
This combination is flagged
GH secretagogues combined with exogenous HGH: Moderate-High risk per peptide research literature. Negative feedback via somatostatin/IGF-1; risk of pituitary suppression; diminishing returns on GH output.
Data-derived verdict
MK-677 has stronger documented evidence (Phase 3 (not approved)) than Ipamorelin (Anecdotal + Phase 2) while both occupy the gh-secretagogue class. When clinical-evidence tier is the deciding factor, MK-677 is the safer pick. Ipamorelin may still fit a specific research framing the higher-evidence option does not cover: cost, dosing convenience, jurisdictional access, or a particular off-label use case.
Evidence at a glance
FDA-approved Phase 3 Phase 2 / approved abroad Anecdotal + animal Preclinical / flagged
Side-by-side
| Ipamorelin | MK-677 | |
|---|---|---|
| Class | Growth hormone-releasing peptide (GHRP); ghrelin receptor agonist | Oral non-peptide ghrelin receptor agonist |
| Drug class | Growth Hormone Secretion | Growth Hormone Secretion |
| Mechanism | Selective GHS-R1a (ghrelin receptor) agonist on pituitary; no cortisol or prolactin rise | GHS-R1a agonist; stimulates pulsatile GH/IGF-1 release; orally bioavailable spiropiperidine |
| Route | SC injection | Oral |
| Half-life | ~2 hrs | ~24 hrs |
| Dosage (research) | 200 mcg SC 2x daily (Seeds Vol 1 starting protocol, range up to 300 mcg 3x daily per r/Peptides wiki, often stacked with CJC-1295 no-DAC) | 12.5 mg oral daily (community starting dose to mitigate water retention and appetite increase, escalate to label dose 25 mg/day per MK-0677-014 Phase 3 protocol) |
| Evidence tier | Anecdotal + Phase 2 | Phase 3 (not approved) |
| Research depth | 91 indexed | 168 indexed |
| Availability | Compounding Restricted | Research Chemical |
| Reported risks | Mild fatigue; headache; injection site reactions; elevated IGF-1 theoretical | Increased hunger; water retention; insulin resistance risk; lethargy; CHF risk (elderly trials) |
Reported research data only. "Studied for" and "reported in literature" describe published research focus, not clinical recommendation. Most peptides catalogued here are not FDA-approved for human use.
Frequently asked questions
Should I pick Ipamorelin or MK-677?
MK-677 has stronger documented evidence (Phase 3 (not approved)) than Ipamorelin (Anecdotal + Phase 2) while both occupy the gh-secretagogue class. When clinical-evidence tier is the deciding factor, MK-677 is the safer pick. Ipamorelin may still fit a specific research framing the higher-evidence option does not cover: cost, dosing convenience, jurisdictional access, or a particular off-label use case.
What is the difference between Ipamorelin and MK-677?
Ipamorelin is classed as Growth hormone-releasing peptide (GHRP); ghrelin receptor agonist; MK-677 is classed as Oral non-peptide ghrelin receptor agonist. Reported mechanism: Ipamorelin, Selective GHS-R1a (ghrelin receptor) agonist on pituitary; no cortisol or prolactin rise; MK-677, GHS-R1a agonist; stimulates pulsatile GH/IGF-1 release; orally bioavailable spiropiperidine. Reported half-life: Ipamorelin, ~2 hrs; MK-677, ~24 hrs. Routes in published studies: Ipamorelin, SC injection; MK-677, Oral.
Which has stronger evidence, Ipamorelin or MK-677?
MK-677 has the stronger evidence base on PeptideHelper.org's five-step evidence scale, which runs from preclinical to FDA-approved. Ipamorelin is graded Anecdotal + Phase 2, with 9 cited sources on its reference page and 91 indexed studies. MK-677 is graded Phase 3 (not approved), with 5 cited sources on its reference page and 168 indexed studies.
Which is more accessible, Ipamorelin or MK-677?
Neither Ipamorelin nor MK-677 is an FDA-approved drug. Catalog status: Ipamorelin, Compounding Restricted; MK-677, Research Chemical. FDA lists Ipamorelin in category 2 of its bulk-substance compounding policy (503B, added September 29, 2023). FDA lists MK-677 in category 2 of its bulk-substance compounding policy (503A; 503B, added 503A: September 29, 2023 503B: December 29, 2022).
Are Ipamorelin and MK-677 ever combined?
Ipamorelin and MK-677 appear together in no stack catalogued on PeptideHelper.org, and the interaction engine raises no flag for the pair.
Open the PeptideHelper.org compare tool to add more compounds to this side-by-side and filter by evidence tier interactively.
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