MK-677 (ibutamoren) is an unapproved compound with no medically validated dosing regimen. The figures below describe what published trials administered and what community sources commonly report. They are educational data points, not a protocol for the reader.
Overview
MK-677 dosing discussions have an anchor most gray-market compounds lack: actual human trials. Published studies administered oral doses from 2 to 25 mg once daily, and 25 mg once daily was the dose carried into every major efficacy trial — in healthy older adults, dieting volunteers, Alzheimer's patients, and hip-fracture patients. Community and vendor sources most often describe 10–25 mg daily, which tracks the studied range. No regulator has ever validated any dose as safe or effective, because the compound was never approved.
Doses used in clinical trials
2, 10, and 25 mg daily — the dose-ranging study in 32 healthy elderly adults; GH rose dose-dependently, with 25 mg raising 24-hour GH concentrations about 97% and lifting IGF-1 into the young-adult range (J Clin Endocrinol Metab 1996).
25 mg daily for 2 years — the Nass trial in 65 healthy adults aged 60–81, the longest exposure on record, which sustained young-adult GH/IGF-1 levels but raised fasting glucose (Ann Intern Med 2008).
25 mg daily — the diet-catabolism study (7 days, n=8), the obese-men study (8 weeks, n=24; JCEM 1998), the 563-patient Alzheimer's trial (Neurology 2008), and the hip-fracture trial that was stopped for safety (Arch Gerontol Geriatr 2011).
Community reports of 10–25 mg once daily, sometimes taken at night, are anecdotal — but unlike most research chemicals, they at least sit inside a range that trials characterized.
Why once daily, and why oral
MK-677 exists because Merck wanted a GH secretagogue that survives digestion. As a non-peptide small molecule it is orally bioavailable — no reconstitution, no injections — and it is long-acting enough that a single daily dose sustains elevated GH and IGF-1 around the clock, in contrast to the brief pulse produced by injectable secretagogues like ipamorelin. That is why every trial used simple once-daily administration, and why splitting doses has no support in the literature. Evening dosing in community practice is usually justified by GH's natural nighttime pulse and the drowsiness some users report; the trials themselves did not establish that timing matters.
The dose–response trade-off
The dose-ranging data carry an inconvenient finding: the same doses that raise GH also disturb glucose metabolism. Fasting glucose rose significantly at GH-effective doses in the elderly dose-finding study (JCEM 1996), insulin sensitivity declined over a year at 25 mg (Ann Intern Med 2008), and glucose tolerance was impaired within two weeks in obese men (JCEM 1998). No published dose separates the hormonal effect from the metabolic cost — "lower dose, hormone benefit only" is a forum hypothesis, not a trial finding.
Why oversight matters
The known effects — raised fasting glucose, reduced insulin sensitivity, fluid retention, and a heart-failure signal in frail patients — are the kind that show up on lab work and clinical exam, not in the mirror. That is the practical argument for clinical oversight and glucose monitoring in any legitimate research context, and against unsupervised use of a compound whose gray-market versions carry FDA warning letters and unverified dosing (FDA, 2023). For the full risk picture, see MK-677 side effects and safety context.