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)
- wellness_wade rated it 5/5 - Gradual but consistent results: About 3 months into my MK-677 (Ibutamoren) protocol and the compound is doing what it is supposed to. Sleep is deeper, skin quality is better, fat around the midsection is slowly reducing, and my recovery from training is improved. The key insight I have learned is patience. This is not an overnight transformation. It is a slow, steady optimization that compounds over weeks and months. People who quit after 2 weeks are not giving it enough time. Only downsides: some mild joint stiffness early on (actually a sign it is working) and the fasted dosing schedule is sometimes inconvenient. Worth i
- measured_mike rated it 5/5 - Body comp changes subtle but real: About 3 weeks into my MK-677 (Ibutamoren) protocol and the compound is doing what it is supposed to. Sleep is deeper, skin quality is better, fat around the midsection is slowly reducing, and my recovery from training is improved. The key insight I have learned is patience. This is not an overnight transformation. It is a slow, steady optimization that compounds over weeks and months. People who quit after 2 weeks are not giving it enough time. Only downsides: some mild joint stiffness early on (actually a sign it is working) and the fasted dosing schedule is sometimes inconvenient. Worth it
- loading_phase_lucy rated it 4/5 - Sleep quality improvement was the first thing I noticed: Running MK-677 (Ibutamoren) for 3 weeks now, primarily for recovery and body composition. The first benefit I noticed was dramatically better sleep, deeper and more restorative, within the first week. Body composition changes came slower but are real. Leaner midsection, slightly fuller muscles, and my recovery between training sessions is noticeably improved. Not dramatic bodybuilder gains, more like everything works a bit better. Side effects have been minimal. Some water retention in the first 2 weeks that settled down, and occasional numbness in my fingers in the morning that goes away wi
- loading_phase_lucy rated it 4/5 - Clean GH pulse without the sides: Running MK-677 (Ibutamoren) for 2 weeks now, primarily for recovery and body composition. The first benefit I noticed was dramatically better sleep, deeper and more restorative, within the first week. Body composition changes came slower but are real. Leaner midsection, slightly fuller muscles, and my recovery between training sessions is noticeably improved. Not dramatic bodybuilder gains, more like everything works a bit better. Side effects have been minimal. Some water retention in the first 2 weeks that settled down, and occasional numbness in my fingers in the morning that goes away wi
- compound_curious rated it 5/5 - Better recovery and deeper sleep at 2 weeks: MK-677 (Ibutamoren) has been a solid addition to my protocol. The GH release translates to better sleep, improved recovery, and a gradual improvement in body composition that I did not get from training alone. I track my sleep with a wearable and my deep sleep percentage went from 12% to about 18-20% within the first two weeks. That alone is worth it for recovery. The body comp changes are more subtle but visible in progress photos over 2-3 months. No significant side effects at the doses I am running. Occasionally wake up with slightly puffy hands but it resolves within an hour. Recommend s
- 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.
Compare MK-677 (Ibutamoren)
Research and educational reference only. Not medical advice.