MK-677
Also known as: Ibutamoren · Nutrobal
An orally active, non-peptide growth hormone secretagogue that mimics ghrelin signaling to produce sustained elevations in GH and IGF-1.
Overview
MK-677 (Ibutamoren) is technically not a peptide but a non-peptide spiropiperidine compound that functions as a potent, orally active growth hormone secretagogue. It mimics the action of ghrelin by binding to the growth hormone secretagogue receptor (GHS-R1a) in the brain, stimulating growth hormone release from the pituitary. What makes MK-677 unique is its oral bioavailability — unlike most peptides that require injection, MK-677 can be taken as a capsule or liquid. It produces sustained elevations in GH and IGF-1 levels for up to 24 hours after a single dose, without significantly altering cortisol levels.
Clinical studies have shown that MK-677 can increase IGF-1 levels by 40-89% in elderly subjects, with improvements in body composition, sleep quality, and bone mineral density. However, it does increase appetite significantly (due to its ghrelin-mimetic action) and can affect insulin sensitivity with prolonged use.
Mechanism of Action
Non-peptide agonist of the ghrelin/growth hormone secretagogue receptor (GHS-R1a). Stimulates GH release through hypothalamic and pituitary pathways. Also increases appetite through ghrelin-like signaling in the arcuate nucleus.
Key Benefits
Potential Side Effects
Common Stacks
This peptide is commonly combined with the following compounds for synergistic effects:
Known Interactions
The following interactions have been documented for MK-677. Always consult a healthcare professional before combining compounds.
Use Caution (2)
MK-677 increases appetite significantly while semaglutide suppresses it. The opposing effects may reduce the efficacy of either compound's primary benefit.
Both raise IGF-1 levels significantly. Combined use may push IGF-1 to supraphysiological levels, increasing risk of unwanted cell proliferation.
Synergistic (2)
CJC-1295 (GHRH analog) combined with MK-677 (oral ghrelin mimetic) provides dual-pathway GH stimulation with the convenience of oral + injectable dosing.
MK-677 can raise blood glucose and insulin. Metformin helps counteract this by improving insulin sensitivity, making the combination more metabolically favorable.
Scientific References
Quick Reference
Typical Dose
10-25 mg
Frequency
Once daily, typically before bed
Route
Oral
Half-Life
~24 hours
Cycle Length
8-12 weeks on, 4 weeks off
FDA Status
Not FDA approved; investigational drug
Need to calculate dosing?
Use our reconstitution calculator to determine exact syringe measurements.
Open CalculatorThis information is for educational purposes only. Consult a qualified healthcare professional before using any peptide. Dosing information reflects commonly reported protocols and may not be appropriate for everyone.
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