For clinicians
MK-677 (ibutamoren) for prescribers: status, evidence and what FDA has said
A neutral reference. It reports MK-677 (ibutamoren)'s regulatory status, the quality of its human evidence and what FDA has said about it. It does not suggest a dose, a protocol or a source.
Status reviewed 2026-10-01 · By the Grey Peptides Editorial Board · Regulatory fields generated from our tracker
| Also known as | — |
| FDA approval | Not FDA-approved |
| Compounding (503A) | Category 2 (safety risks): not compoundable |
| Outsourcing (503B) | 503B Category 2: FDA has identified significant safety risks |
| WADA 2026 List | Prohibited (S2.2.4) |
| WADA 2027 List | Prohibited (S2.2.4) |
| Evidence grade | Medium |
| Status reviewed | 2026-10-01 |
What FDA has said
FDA lists Ibutamoren mesylate in Category 2, the substances it has found may present significant safety risks (page current as of 2026-04-22). In FDA's words:
Ibutamoren mesylate poses significant safety risks due to the potential for congestive heart failure in certain patients. The agency is aware of a randomized, placebo-controlled trial assessing ibutamoren mesylate for the treatment of patients recovering from hip fracture that “was terminated early due to a potential safety signal of congestive heart failure.”
Monitoring: what the literature does and does not say
- No label. MK-677 (ibutamoren) has no FDA-approved label, and therefore no labelled guidance on monitoring.
- What FDA has said about its risks is quoted above, from its list of bulk substances that may present significant safety risks.
These are gaps, not a monitoring schedule. This page does not supply one, and for a compound in this position the human evidence would not support one.
Compounding: where it stands
Today's position for MK-677 (ibutamoren): Category 2 (safety risks): not compoundable. An FDA advisory committee's vote is a non-binding recommendation; until FDA acts, a vote does not change what may be compounded. Our explainer on the 503A and 503B categories sets out what each status means, and the regulatory tracker is updated as FDA acts.
The evidence
An oral, non-peptide ghrelin-receptor agonist: it raised growth hormone and IGF-1 for months in trials and added lean mass in older adults, but failed in Alzheimer's and hip-fracture recovery, raised blood sugar and was never approved.
The encyclopedia entry lists the human and animal studies we hold, each with its PMID.
What this page leaves out
Doses, regimens, cycle lengths and sources. That is deliberate. A reference that reports status and evidence is useful only if it is not also a protocol, and for a compound in this position there is no approved one to report.
Sources
- US Food and Drug Administration. Certain Bulk Drug Substances for Use in Compounding that May Present Significant Safety Risks. Content current as of 2026-04-22; read 2026-10-01. FDA
- Grey Peptides regulatory tracker, row for MK-677 (ibutamoren), reviewed 2026-10-01. Tracker · dataset
- World Anti-Doping Agency. Prohibited List 2027, dated August 26, 2026, in force January 1, 2027. WADA
This page is a reference for qualified professionals. It is not medical advice, it does not recommend any treatment, and it is not a substitute for the prescriber's own judgement and their state and federal obligations.
Others in this group: AOD-9604 · Cathelicidin (LL-37) · Cerebrolysin · CJC-1295 · Dihexa · GHK-Cu (injectable) · GHRP-6 · Hexarelin · Ipamorelin · Melanotan II · Noopept · PEG-MGF · Pralmorelin (GHRP-2) · Selank · Sermorelin · Tesofensine · Thymopentin · Thymosin α-1