MK-677 (Ibutamoren)
Ibutamoren mesylate (MK-0677, L-163,191)
Access and compounding status raise extra safety and legal questions.
An oral daily compound (ibutamoren) that mimics ghrelin (the body's hunger hormone) to raise growth hormone levels, studied in people for building lean muscle and improving bone density. It is not a peptide, is not FDA-approved, and requires careful medical monitoring due to effects on blood sugar and heart health, particularly in older adults.
This entry is a cited research summary, not an established treatment reference. Dosing language is included as source context, not as medical instruction.
MK-677 (Ibutamoren) has moderate clinical evidence but is not FDA-approved.
Access and compounding status raise extra safety and legal questions.
Safety Summary
Most common side effects (appetite increase, water retention) are most prominent in the first 1-2 weeks and may partially attenuate. Insulin resistance is dose-dependent and more concerning with chronic use, particularly in individuals with pre-existing metabolic risk. Insulin resistance may be managed through dietary modification and dose reduction. The CHF signal occurred in elderly, frail patients with potential pre-existing cardiovascular vulnerability. Long-term safety data beyond 1-2 years is limited. Sustained IGF-1 elevation raises theoretical concerns about tumor promotion, though no clinical data confirm this risk with MK-677 specifically. Monitoring of blood glucose and insulin sensitivity recommended
Clinical check-in
If real-world use or exposure is being considered, review potential interactions, contraindications, and monitoring needs with a licensed clinician rather than relying on summary copy alone.
Cited sources
Every claim on this page links to one of the 8 sources below. Identifiers are PubMed (PMID), ClinicalTrials.gov (NCT), or DOI; click through to the source of record before acting on a claim.
- 1PMID 18981485PubMed
- 2PMID 19015485PubMed
- 3PMID 21067829PubMed
- 4PMID 8954023PubMed
- 5PMID 9467534PubMed
- 6NCT06948214ClinicalTrials.gov
- 7NCT00116129ClinicalTrials.gov
- 8PMID 40675653PubMed