MK-677 (Ibutamoren) (Ibutamoren Mesylate (MK-677))
An orally active non-peptide GH secretagogue that mimics ghrelin signaling. Increases GH and IGF-1 for 24 hours from a single oral dose.
How it works
Acts as ghrelin mimetic at GHS-R1a receptors in hypothalamus and pituitary. Excellent oral bioavailability and 24-hour duration.
Key facts
- Molecular weight: 528.7 Da
- Half-life: 24 hours
- Bioavailability: High (oral)
- Storage: Room temperature, protected from light.
Dosing overview
- Typical dose: 10-25 mg
- Frequency: Once daily
- Duration: 12-24 week cycles
- Route: Oral (capsule/liquid)
Protocol notes
- Most start at 10 mg/day and assess for water retention and hunger before going to 25 mg.
- Taken as a single daily oral dose - no injecting and no fasting requirement.
- Often run in 3-6 month blocks because benefits (sleep, recovery, appetite) build over time.
Reported benefits
- Oral administration
- Sustained 24h GH elevation
- Increased IGF-1
- Improved sleep depth
- Enhanced recovery
- Bone density support
Possible side effects
- Increased appetite
- Water retention/edema
- Insulin resistance (long-term)
- Lethargy
- Joint pain
- Numbness
Research
- Two-year MK-677 treatment in elderly (2008): Reversed diet-induced nitrogen wasting, increased lean mass by 1.5kg, and elevated IGF-1 to young-adult levels.
- Effects of ibutamoren on bone mineral density (2019): 12 months increased BMD at femoral neck by 3.2% with sustained IGF-1 elevation.
Community reviews of MK-677 (Ibutamoren)
- sanjay_swims rated it 5/5 - fixed my dead sleep after late gym sessions: i tried mk-677 after a few weeks of rubbish sleep from late training and coding, proper grotty stuff here in the uk winter. after about 3 weeks, i was sleeping deeper and waking less knackered. for me it was very noticeable, though could just be my own experience.
- lifter_former rated it 5/5 - mk-677 made my sleep feel properly deep: i ran mk-677 for about 6 months while i was juggling grad work, lifting, and the usual canadian winter slog, and for me the biggest change was waking up less wrecked and recovering better between sessions. it seemed to help my sleep depth and made training feel more sustainable, tbh. i didn’t feel like a superhero, just like my body was keeping up for once. for me, that was enough to rate it 5 stars.
- coastal_chemist rated it 5/5 - Good sleep, but my pants noticed it: I ran MK-677 for about 4 months, mostly because at 40-something, teaching yoga on the East Coast and lifting a few days a week, I was tired of feeling half-recovered all the time, and I wanted to see if the sleep claim was real. For me, it did seem to deepen sleep and I woke up less wrecked, which was a big deal during winter when everything feels a little beat up anyway. The downside was hunger, plain and simple, it made me want to eat like a linebacker 😅 I also held a bit more water, so my waist got tighter before I liked it. Still, I’d give it 5 stars from my own experience.
- tired_vo2max rated it 4/5 - MK-677 Helped My Sleep, But CJC Still Wins for Me: I ran MK-677 for about 12 weeks while coaching CrossFit and trying to keep up with my own training in the South heat, and it did make my sleep feel deeper, which I was chasing hard. I woke up a little fuller too, which was nice for recovery. tbh though, I liked CJC-1295 better for the same goal, it felt cleaner to me with less of that all-day hungry feeling. MK still earned 4 stars from me 🙂
- rational_reads rated it 4/5 - Good sleep, but the hunger was rude: I ran MK-677 for about 10 weeks while I was lifting after work and chasing sales around NZ, and yeah, my sleep felt deeper and recovery seemed a bit better. The annoying part was the hunger, it was constant and made cutting way harder for me. Still a solid 4/5.
- evan_w rated it 2/5 - puffy hands and no real sleep upgrade, 2 stars from me: tried this at 55 hoping for deeper sleep since my writing deadlines wreck my schedule. ten weeks, just felt bloated and my fingers ached in the morning. honestly a strict magnesium glycinate before bed did more for my sleep depth than this ever did, for what it is worth.
Compare MK-677 (Ibutamoren)
Research and educational reference only. Not medical advice.