Track MK‑677 in Peptimes™
MK-677 is ibutamoren, a small synthetic molecule with the formula C27H36N4O5S. FDA's substance registry lists its mesylate salt as MK-677 and MK-0677. (Source: FDA's substance registry (GSRS).)
Is MK-677 FDA-approved?
No. MK-677 (ibutamoren) is investigational and isn't FDA-approved: Drugs@FDA lists no application with it, and FDA puts ibutamoren mesylate on its Category 2 list for compounding.
MK-677
Also: ibutamoren, ibutamoren mesylate, MK-0677, L-163,191, LUM-201
- Status label in the Peptimes Library
- Compounding Restricted
- Routes in Peptimes
- Oral
- Updated
- 1 Nov 2026
US regulatory status
FDA status
Not FDA-Approved. Drugs@FDA lists no application with ibutamoren (MK-677) as an active ingredient.
Source: Drugs@FDA, checked 1 Nov 2026
FDA status
On FDA's Category 2 list: FDA lists ibutamoren mesylate among bulk drug substances for compounding that may present significant safety risks, under its interim policies for pharmacies (503A, added 29 Sep 2023) and outsourcing facilities (503B, added 29 Dec 2022).
Source: FDA, checked 1 Nov 2026
Investigational
Yes.
Source: ClinicalTrials.gov, checked 1 Nov 2026
How to track it in Peptimes
Add MK-677 in My Protocols and set the schedule you already follow: days of the week, times of day and a start date. Peptimes never suggests an amount when you log or schedule a dose. Its Library entry shows the status label “Compounding Restricted”, the app’s label for compounds on FDA’s Category 2 list. Category 2 is FDA’s list of bulk drug substances for compounding that may present significant safety risks; it is not an approval. Ibutamoren is also being studied in clinical trials as LUM-201; that isn’t an approval.
- Logging: the amount you took and how you feel.
- Reminders and history: reminders at your times, Dose History, the Calendar and CSV or JSON export work as described on the peptide tracker app page.
Peptimes is a tracking app, not medical advice. Talk to a licensed clinician about your treatment. Peptimes doesn’t sell MK-677 or any other compound.
More sources
- FDA, Certain bulk drug substances for use in compounding that may present significant safety risks, checked 1 Nov 2026: ibutamoren mesylate, 503A (added 29 Sep 2023) and 503B (added 29 Dec 2022).
- FDA, Global Substance Registration System, Ibutamoren and ibutamoren mesylate, checked 1 Nov 2026: its formula, and the names MK-677, MK-0677 and L-163,191.
- NIH, ClinicalTrials.gov, NCT06948214, checked 1 Nov 2026: a Phase 3 study of LUM-201 sponsored by Lumos Pharma, recruiting. Studies of ibutamoren on ClinicalTrials.gov include the LUM-201 studies.