MK-677 has more real human clinical trial data than almost any other compound discussed on this site — here's what it actually shows.
🧪 A 2-year randomized controlled trial — one of the longest in this category
📈 +1.1 kg fat-free mass vs -0.5 kg with placebo (p<0.001)
⚠️ Fasting glucose +0.3 mmol/L and reduced insulin sensitivity in the same trial
💊 Oral capsule — no reconstitution or injection required
MK-677 (Ibutamoren) is an orally active, non-peptide growth hormone secretagogue. Unlike Ipamorelin or CJC-1295, it doesn't require reconstitution or injection — it's taken as a capsule and has a long half-life, which is a major reason it has been more extensively studied in formal human clinical trials than most other GH secretagogues discussed on this site.
MK-677 activates the ghrelin receptor (GHS-R1a), stimulating pulsatile growth hormone release from the pituitary and, as a downstream effect, raising IGF-1 levels produced by the liver. This GH/IGF-1 axis mechanism is the same broad pathway targeted by injectable secretagogues, but MK-677's oral bioavailability and multi-hour half-life let researchers study sustained, once-daily dosing rather than short-acting pulses.
The most rigorous human data on MK-677 comes from a specific, real, published trial — not from anecdotal or forum-based claims:
A 2-year, double-blind, randomized, placebo-controlled trial enrolled 65 healthy older adults (ages 60–81 — 23 men, 25 women on hormone replacement therapy, and 17 women not on HRT) and randomized them to oral MK-677 at 25 mg/day or placebo. This is one of the longest controlled human trials of any GH secretagogue discussed on this site.
MK-677 restored GH and IGF-1 levels to those typically seen in younger adults over the 2-year trial period. On body composition, fat-free mass increased by 1.1 kg in the MK-677 group, versus a 0.5 kg decrease in the placebo group — a statistically significant difference (p<0.001).
Nass et al. 2008 found MK-677 restored GH and IGF-1 to young-adult reference levels over 2 years.
+1.1 kg lean mass vs a 0.5 kg decrease with placebo — a real, statistically significant controlled-trial result.
Separate published trials have examined MK-677's effects on slow-wave sleep in older adults and muscle-wasting populations.
No reconstitution or injection — one of the few secretagogues on this site with a simple oral capsule protocol in its trial data.
The figure below is reported strictly as trial data — not usage guidance. There is no FDA-approved dosage for MK-677 for any general-population use.
| Context | Dose Tested | Source |
|---|---|---|
| Nass et al. 2008 (ages 60–81) | 25 mg/day, oral, 2 years, clinically supervised | Annals of Internal Medicine, 2008 |
| Other published trials (muscle-wasting / pediatric GHD research) | Varies by study design and population | Multiple published trials |
Compound X does not provide dosing recommendations. MK-677 is sold for laboratory research use only and is not intended for human consumption.
The Nass et al. trial's 2-year safety data is some of the most complete available for any compound on this site. Reported findings included:
The glucose and insulin-sensitivity findings are worth taking seriously — they were measured in a controlled 2-year trial, not a short-term or anecdotal report. MK-677 is not FDA-approved for any indication.
No, despite often being grouped with SARMs in online discussion. MK-677 is a growth hormone secretagogue with a completely different mechanism — it doesn't touch the androgen receptor at all.
The Nass et al. 2008 trial found a measurable increase in fasting glucose and a decrease in insulin sensitivity over 2 years of use — a real, replicated finding rather than an unconfirmed concern.
It is not FDA-approved for any use and is not classified as a controlled substance in most jurisdictions, but it is sold strictly as a research chemical labeled "not for human consumption."
Nass R, Pezzoli SS, Oliveri MC, et al. "Effects of an Oral Ghrelin Mimetic on Body Composition and Clinical Outcomes in Healthy Older Adults: A Randomized, Controlled Trial." Annals of Internal Medicine. 2008;149(9):601-611. Additional MK-677 clinical trial data is indexed on PubMed under "MK-677 Ibutamoren growth hormone secretagogue."
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