Muscle GrowthAnti-AgingSleepWell-evidencedHuman trials

MK-677

Ibutamoren

Overview

MK-677 (Ibutamoren) is a potent orally active growth hormone secretagogue and ghrelin receptor agonist that stimulates the pituitary gland to release growth hormone and IGF-1. Unlike injectable GH secretagogues it is taken as a daily oral tablet making it one of the most accessible GH-stimulating compounds available. MK-677 has completed multiple clinical trials demonstrating increases in GH and IGF-1 levels improvements in lean body mass bone density and sleep quality. It is widely used in the research community for muscle growth anti-aging applications and improving recovery.

Mechanism of Action

MK-677 acts as a selective agonist of the ghrelin receptor (GHSR-1a) mimicking the action of ghrelin — the endogenous hunger and GH-releasing hormone. By binding to GHSR-1a in the pituitary gland and hypothalamus MK-677 stimulates the pulsatile release of growth hormone through pathways that complement and enhance those activated by GHRH. Unlike exogenous GH administration MK-677 preserves the natural pulsatile pattern of GH secretion and works through the body's own regulatory feedback mechanisms. The resulting GH pulse stimulates hepatic IGF-1 production which mediates downstream anabolic effects including muscle protein synthesis lipolysis and tissue repair. MK-677 also increases deep sleep duration by enhancing slow-wave sleep — an effect mediated through central ghrelin receptor activation in sleep-regulating brain circuits.

Where does MK-677 sit?

See how this peptide compares across all 85 peptides in our database.

Dosage Information

Typical Dose

10-25 mg daily

Frequency

Once daily, typically at bedtime

Administration

Oral capsule or liquid

Notes

Bedtime dosing takes advantage of the sleep-enhancing effects and aligns with the natural nocturnal GH pulse. Lower doses (10mg) minimize water retention and appetite stimulation while preserving most GH benefits.

Compound Data

MK-677 structure

Molecular Formula

C28H40N4O8S2

Molecular Weight

624.80 g/mol

IUPAC Name

2-amino-2-methyl-N-[(2R)-1-(1-methylsulfonylspiro[2H-indole-3,4'-piperidine]-1'-yl)-1-oxo-3-phenylmethoxypropan-2-yl]propanamide;methanesulfonic acid

PubChem CID

6450830

Potential Side Effects

Increased appetite — significant and commonWater retention and mild edema (common)Fatigue or lethargy especially initially (common)Elevated fasting glucose — monitor in pre-diabetics (uncommon)Tingling or numbness in extremities (uncommon)Joint pain at higher doses (uncommon)

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Quick Facts

Administration
Oral capsule or liquid
Typical Dose
10-25 mg daily
Frequency
Once daily, typically at bedtime
References
0 curated + 48 from PubMed
Clinical Trials
8 registered
Evidence Score
80.0 / 100