MK-677 (Ibutamoren)
MK-677 (Ibutamoren) is a non-peptide oral growth hormone secretagogue that mimics ghrelin and binds the ghrelin receptor (GHSR). It increases growth hormone and IGF-1 levels without affecting cortisol. Notable for its oral bioavailability (no injections needed) and long half-life (24 hours), MK-677 is popular for improving sleep quality, body composition, bone density, and recovery. It provides sustained GH elevation compared to injectable GH peptides.
Frequency
1-2 times daily
Cycle Length
8-16 weeks. Some use ongoing at lower doses (10 mg).
Route
Oral
Research Level
Established
Goals
Dosing Protocol
10-50 mg daily, taken orally (25 mg tablets). 1 to 2 tablets per day. Take on empty stomach; if taking once daily, take at night before bed.
Timing
For muscle gain, take during the day. For sleep and repair, take before bed. If taking once daily, take at night before bed on empty stomach.
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Potential Side Effects
- Increased appetite
- Water retention and bloating
- Numbness/tingling in hands
- Lethargy
- Elevated blood sugar with long-term use
Important Warnings
- May elevate blood sugar — monitor fasting glucose during use
- Not suitable for diabetics without medical supervision
- Do not use with active cancer
- WADA-prohibited substance
Frequently Asked Questions
What is MK-677 used for?
MK-677 is used for growth-hormone support, recovery, sleep quality, and body-composition goals. It is popular because it raises GH and IGF-1 while being taken orally rather than injected.
Is MK-677 a peptide?
MK-677 is not technically a peptide. It is an oral non-peptide ghrelin receptor agonist that is often discussed alongside peptide protocols because it targets the same growth-hormone axis.
When should MK-677 be taken?
Timing depends on the goal and side effects. Some people take it at night to lean into sleep and recovery benefits, while others use daytime dosing if appetite and lethargy are easier to manage then.
What side effects are common with MK-677?
The most common MK-677 side effects are increased appetite, water retention, bloating, lethargy, tingling in the hands, and elevated blood sugar with longer-term use.
Research References
- Nass R, et al. J Clin Endocrinol Metab. 2008;93(4):1198-1206. doi:10.1210/jc.2007-2232
- Murphy MG, et al. J Clin Endocrinol Metab. 1998;83(2):320-325. doi:10.1210/jcem.83.2.4539
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Medical Disclaimer: This information is for educational purposes only and is not intended as medical advice. MK-677 (Ibutamoren) may be regulated differently in various jurisdictions. Always consult with a qualified healthcare provider before beginning any peptide protocol. PepStack Pro does not sell peptides or provide medical advice. Content reviewed by Dr. Seth Miller, MD.