MK-677 (ibutamoren) is an oral, non-peptide drug that mimics the hormone ghrelin and triggers growth hormone release. It was developed by Merck and is not FDA approved.
Also known as: ibutamoren, ibutamoren mesylate, MK-0677.
There is no approved product. Published trials used 2, 10 or 25 mg a day in older adults (Chapman 1996) and 25 mg a day for up to 2 years (Nass 2008).
MK-677 is not FDA approved. FDA has placed ibutamoren mesylate in Category 2 of its 503A compounding list (substances that raise significant safety risks), citing a possible risk of congestive heart failure: a trial in hip-fracture patients was stopped early over that safety signal. FDA warning letters treat products sold as MK-677 as unapproved new drugs.
In published trials, MK-677 raised fasting blood sugar in older adults (Chapman 1996) and lowered insulin sensitivity over 2 years; the most common side effects were increased appetite and mild, short-lived leg swelling and muscle pain (Nass 2008). These are trial protocols, not personalized advice; confirm any dosing with your prescriber.
We could not open a primary human pharmacokinetic study of MK-677. A later trial (Campbell 2018) cites the company's unpublished investigator brochure for a plasma half-life of 6 to 13 hours, which we cannot check, and we found no published time to peak. So we do not list the app's 6-hour and 1.75-hour modeling values.