MK-677
Also known as Ibutamoren, Nutrobal
An orally active, non-peptide growth hormone secretagogue that mimics ghrelin to stimulate sustained GH and IGF-1 release. MK-677 is popular for muscle building, recovery, and improved sleep quality. Not a true peptide but frequently categorized alongside them.
| Typical dose | 10-25 mg |
|---|---|
| Frequency | Once daily (oral) |
| Half-life | ~24 hours |
| Cycle length | 8-16 weeks (some use longer) |
| Research level | extensive |
| Prescription required | No |
Mechanism of action
Binds the ghrelin/GHS-R1a receptor to stimulate GH release from the pituitary in a pulsatile manner. Increases IGF-1 levels sustained over 24 hours, promotes nitrogen retention, and enhances deep sleep architecture.
What this means in practice
MK-677 is orally active, which sets it apart from nearly everything else in this library — no reconstitution, no injections. That convenience is also why it's frequently misused: the long half-life means it's taken daily, and the appetite increase is pronounced and sustained rather than transient. It's a growth hormone secretagogue rather than a peptide in the strict sense. Water retention and elevated fasting glucose are the effects most commonly reported, and both are dose-dependent.
Reported side effects
- Increased appetite
- Water retention
- Lethargy
- Elevated blood sugar
- Numbness/tingling
Commonly stacked with
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Get Optim on Google Play →This page is informational and summarises publicly available research. It is not medical advice, not a prescription, and not a recommendation to use any compound. Most compounds described here are not approved by the FDA for human use. Legal status varies by jurisdiction and is yours to determine. Talk to a qualified clinician before starting, stopping, or changing any protocol. For adults 18+. Optim does not sell, source, or recommend suppliers.