MK-677
Also known as: Ibutamoren, Nutrobal, L-163,191
An oral growth hormone secretagogue with 24-hour activity.
Overview
MK-677 is an orally active, non-peptide growth hormone secretagogue that mimics ghrelin's GH-stimulating effects. Its oral bioavailability and long duration make it unique among GH secretagogues.
Mechanism of Action
Agonist at ghrelin receptors (GHS-R1a) in pituitary and hypothalamus. Increases GH pulsatility and amplitude. Also increases appetite and may affect sleep architecture.
Pharmacokinetics
Oral bioavailability ~60%. Half-life 4-6 hours but effects last 24 hours due to IGF-1 elevation. Peak GH at 1-2 hours.
Dosing Protocols
Note: These are research protocols from literature. This is not medical advice.
Standard
10-25 mg
Once daily
8-12 weeks
Evening dosing may enhance sleep benefits
Stacking Recommendations
Peptides that may be combined based on complementary mechanisms in research settings.
Research Areas
Key Research Findings
- 1Increased GH and IGF-1 to youthful levels in elderly
- 2Improved sleep quality and REM sleep
- 3Increased lean mass and bone mineral density
- 4Maintained efficacy over 12+ months without significant tachyphylaxis
Side Effects & Contraindications
Reported Side Effects
- Increased appetite
- Water retention
- Lethargy
- Insulin resistance
Contraindications
- Diabetes
- Active malignancy
Safety Considerations
May worsen insulin sensitivity. Water retention common. Increased appetite. Monitor fasting glucose.
Storage Requirements
Store at room temperature, protected from moisture
Scientific References
- 1