Head to head
MK-677 against Sermorelin
An oral non-peptide against an injected GHRH fragment, working on two different receptors that converge on the same pituitary output. Route and half-life differ; approval status differs; the ageing claims attached to both exceed what either has been tested for.
Column A
MK-677Ibutamoren (oral ghrelin receptor agonist)
A non-peptide, orally active ghrelin receptor agonist that raises growth hormone and IGF-1. Completed but did not pass Phase 3 for approval.
Column B
SermorelinSermorelin (GHRH 1-29 analogue)
A GHRH fragment historically approved as a diagnostic and pediatric GH agent, now used in compounded anti-aging research.
Side by side, on the facts we can check
| Attribute | MK-677 | Sermorelin |
|---|---|---|
| Category | Growth Hormone | Growth Hormone |
| FDA status | Not FDA-approved (failed to gain approval after Phase 3) | Previously FDA-approved (Geref, discontinued); available compounded |
| Half-life | ~24 hours | ~10-20 minutes |
| Molecular weight | 624.8 Da | 3,357.9 Da |
| Mechanism | Agonizes the ghrelin/GH secretagogue receptor (GHS-R1a), increasing GH and IGF-1 while also stimulating appetite. | Activates pituitary GHRH receptors to stimulate physiological growth hormone release. |
| Human studies cited | 3 | 1 |
| Legal status, US | Not approved; research use only | Prior approval discontinued; available via compounding pharmacies |
Frequently asked questions
What is the difference between MK-677 and Sermorelin?
MK-677: A non-peptide, orally active ghrelin receptor agonist that raises growth hormone and IGF-1. Completed but did not pass Phase 3 for approval. Sermorelin: A GHRH fragment historically approved as a diagnostic and pediatric GH agent, now used in compounded anti-aging research.
Which has stronger research evidence, MK-677 or Sermorelin?
This database does not grade compounds. It counts what was run in people: 3 of the 3 studies cited on the MK-677 profile were human work, against 1 of 2 for Sermorelin. Those counts are of our own citation lists and understate any larger literature, and neither is a recommendation.
Are MK-677 and Sermorelin FDA-approved?
MK-677: Not FDA-approved (failed to gain approval after Phase 3). Sermorelin: Previously FDA-approved (Geref, discontinued); available compounded.
Related posts
Blog articles that cover MK-677 or Sermorelin, newest first.
Reviewed Sep 2026. This page sets two published records side by side. It is educational, it is not medical advice, and it contains no dosing protocols or recommendations for personal use.