Ibutamoren is a ghrelin receptor agonist, and the property that makes it unusual is that it works orally. The peptide secretagogues, ipamorelin, GHRP-2, GHRP-6, act at the same receptor and are all destroyed in the gut, so they have to be injected. MK-677 is a non-peptide small molecule that survives digestion, which is the entire reason it occupies the niche it does. It is routinely grouped with SARMs and is not one, having no androgen receptor activity at all. Its half life is long enough for once-daily use, again unlike the peptides.
How MK-677 compares
Against ipamorelin and the GHRPs: same receptor, but those are peptides requiring injection and MK-677 is orally active with a much longer duration. Against actual SARMs: no androgen receptor activity, so the shared shelf is misleading. Against GHRH analogues such as CJC-1295: different receptor entirely, which is why the two are studied together rather than as alternatives.
| Class | Orally active ghrelin receptor agonist |
| Also known as | Ibutamoren, Nutrobal |
| Presentation | Oral liquid or capsule. |
| Pharmacokinetics | Approximately 24 hours, which is why it is characterised as once-daily in study design. |
| Storage | Cool, dry, out of direct light. |
Quanta Pharma MK-677 (Ibutamoren) 12.5mgin stock£36
Availability checked 2026-09-08. The product page carries live stock.