In a Phase 3 for children and on the grey market at once
What it actually is
MK-677 is a pill, not an injection. It is a lab made chemical that nudges the body into releasing more of its own growth hormone. The same molecule is in a late stage trial in children right now, under the name LUM-201, and is also sold online, unapproved, as a research chemical.
What it is supposed to do
It switches on the same docking point that the hunger hormone ghrelin uses, which tells the pituitary gland in the head to release a pulse of growth hormone. The growth hormone then raises a blood marker called IGF-1, and this part is not in doubt: IGF-1 went up in every trial ever run, across six populations and three decades. What has never been shown is that the raised marker turns into anything a person would notice.
What people take it for
People take it for muscle size and for sleep, usually swallowed once at night, and it is sold as an oral stand in for growth hormone. That is what people do, not what the trials found: no randomised trial has tested muscle growth, strength or performance in young trained adults, and the entire human sleep record is one 1997 study in 14 people.
The dose question
What circulates
10 to 25 mg once daily
What was studied
25 mg, the top of three arms
A 1996 dose ranging study in 32 people aged 64 to 81
The convention matches a studied dose, but one chosen for being the largest tried in 32 elderly people. Children in the active Phase 3 are dosed per kilogram. Nobody re-derived it for adults.
Reported because it is what people use. Nothing here recommends any amount.
How long it lasts
Nobody has measured this in a person. The roughly 24 hours quoted on vendor pages has no primary human source, and the pages contradict each other.
Route studied
By mouth, as a daily pill
Route used
By mouth, usually one capsule at night
How to check you have the right molecule
There is no chemical fingerprint to compare on a lab report here, so the check is on the certificate. These names all mean the same molecule: MK-677, MK-0677, ibutamoren, ibutamoren mesylate, LUM-201, and Merck's old code L-163,191. These are different molecules whose results do not carry over: anamorelin, capromorelin, ipamorelin, macimorelin, hexarelin, and CJC-1295, which works on a different docking point altogether. The numbers worth knowing are about the products rather than the molecule: of 44 products sold online in one analysis, only 18 held the labelled amount of the labelled compound, and 17 held a different unapproved drug instead, with ibutamoren itself named among the contaminants found in other products. A certificate should cover the batch in your hand and state the amount actually found, not just the name.
The mistake that costs people is trusting a normal fasting blood test. In the trial of 24 obese men, fasting sugar and insulin looked unchanged after eight weeks, while a test that challenges the body with a measured sugar drink showed impaired handling at both two weeks and eight weeks. A clean fasting panel here is reassurance from the one test already shown to under report the effect.
What is known about harm
In the two year trial the usual effects were more hunger, mild swelling in the lower legs, muscle pain, blood sugar rising by about 5 mg/dL, and insulin working less well. One trial in elderly hip fracture patients was stopped early over a heart failure signal and its authors called the safety profile unfavourable, though the case counts behind that were never published, and a single case report describes a man in his thirties whose liver enzymes rose after two months and settled once he stopped. Every one of those numbers comes from people aged 60 and over or from hospital patients. Nobody has run a long trial in healthy young adults, so what it does to them over years is unmeasured.
Everything on this page is a summary. The citations, the studies and the reasoning live in the full entry.