MK-677 (Ibutamoren)

Also known as: Ibutamoren, MK-0677, L-163,191

MK-677 (Ibutamoren) is an orally active, non-peptide ghrelin receptor agonist that mimics the action of ghrelin on the growth hormone secretagogue receptor (GHSR-1a). By binding to this receptor in the pituitary and hypothalamus, it stimulates pulsatile growth hormone (GH) release, leading to sustained elevations in insulin-like growth factor 1 (IGF-1) levels for up to 24 hours following a single dose. Unlike exogenous GH administration, MK-677 preserves the endogenous feedback regulation of the GH/IGF-1 axis. Key research findings from clinical trials indicate that MK-677 increases GH and IGF-1 levels in a dose-dependent manner without significantly altering cortisol or prolactin. Studies have shown improvements in lean body mass, bone mineral density, and muscle strength in elderly populations, as well as potential benefits in conditions such as frailty, sarcopenia, and growth hormone deficiency. However, transient increases in fasting glucose and insulin resistance have been observed, suggesting a need for careful metabolic monitoring. Clinically, MK-677 has been investigated for age-related decline in GH secretion, muscle wasting disorders, and as an adjunct to fracture healing. Despite promising anabolic effects, its development has been limited by metabolic side effects and lack of long-term safety data. It remains an investigational compound with no approved therapeutic indications. For research purposes only — not medical advice.

Key data

Frequently asked questions

Related peptides