MK-677

MK-677 is a lab-made small molecule, not a peptide ^{[6] [16]}. Its drug name is ibutamoren. It also goes by MK-0677 and LUM-201 ^[6]. It copies ghrelin, a hormone made mostly in the stomach. It makes the pituitary gland release growth hormone ^{[6] [11] [18]}. The pituitary is a small gland at the base of the brain. MK-677 is made to be taken by mouth ^{[6] [17]}.

A drug company made it in 1995 and stopped work on it in 1999 ^[6]. Another company now studies it as LUM-201 in children short of growth hormone ^{[6] [19]}. Online, it is sold to build muscle, lose fat, sleep better and slow aging ^[6]. Some sellers call it a SARM. A SARM is a different kind of drug that acts on male hormone receptors. FDA says MK-677 is not a SARM ^[6].

MK-677 is on Category 2, FDA's list of substances that may present significant safety risks in compounding ^{[1] [2]}. That means no pharmacy may lawfully make it ^[3]. It is also in no FDA-approved drug ^[6]. Being on the list does not mean FDA has finished its review ^[3]. Checked 26 October 2026.

FDA keeps lists for two kinds of compounders. A pharmacy is covered by section 503A of the law. An outsourcing facility is covered by section 503B ^{[3] [4]}. FDA put ibutamoren mesylate on the outsourcing Category 2 list on 29 December 2022. It added it to the pharmacy list on 29 September 2023 ^[1]. FDA gave the reason as possible heart failure in some patients ^[1]. FDA's pharmacy list of 14 May 2026 still names it in Category 2 ^[2]. So does its outsourcing list of 21 March 2025 ^[4]. A law firm notes that pharmacies are strictly limited in making any Category 2 substance ^[12].

On 29 October 2024, FDA's Pharmacy Compounding Advisory Committee reviewed it for six uses ^{[5] [7]}. These included growth hormone shortage, weak bones and Alzheimer's disease ^[7]. FDA proposed leaving it off the list of substances pharmacies may use. The committee voted 13 to 1 against adding it ^[7]. A vote is a recommendation. The final decision is FDA's, made through rulemaking ^[3].

MK-677 is not a lawful dietary supplement either. FDA says it was studied as a new drug before anyone sold it as a supplement. That rules it out as a supplement ingredient ^[10]. FDA treats products sold for muscle or growth as unapproved new drugs ^{[8] [10]}. It was reviewed for growth hormone shortage and diseases of aging. It is sold online for muscle and anti-aging ^{[6] [7]}.

The evidence grade is moderate-human: controlled trials show MK-677 raises growth hormone and lean mass ^{[13] [14] [15]}. None showed a gain in strength or health, and most measures of function did not change ^{[13] [14]}.

In 65 healthy adults aged 60 to 81, a year of MK-677 raised growth hormone to young-adult levels ^[13]. Lean mass rose by about 1 kilogram, but strength and function did not change ^[13]. Body weight rose by 2.7 kilograms, against 0.8 on placebo, a dummy pill ^{[13] [22]}.

In 123 older people after a broken hip, MK-677 raised IGF-1 but did not improve most measures of function ^[14]. That trial stopped early over heart failure ^{[14] [21]}. In 563 people with mild to moderate Alzheimer's disease, a year of MK-677 did not slow the disease ^[15]. A small US study tested it in adults with fatty liver disease. It is complete, and this page holds no result from it ^[20].

In beagles, one dose by mouth raised growth hormone for up to six hours ^[17]. In mice bred to model Alzheimer's disease, it reduced plaque in the brain ^[18]. These are animal results, not results in people.

A rise in growth hormone or IGF-1 is a lab marker. It does not by itself show a benefit ^{[15] [16]}. FDA's 2024 review found too little evidence that it helps any of the six uses it reviewed ^[6].

No approved drug in the US contains MK-677, and no pharmacy may lawfully make it ^{[6] [1]}. It cannot be sold as a dietary supplement ^[10].

The only legal route is a clinical trial. A phase 3 trial of LUM-201, another name for MK-677, is recruiting children short of growth hormone at US sites ^[19]. Open trials are listed in the trials block below, with the date the official registry was last checked.

Three ways of getting MK-677 show up in FDA's records ^{[6] [8] [10]}. The first is online sellers that list it beside SARMs, often as a research product. FDA sent warning letters to such sellers in June 2023 and December 2025 ^{[8] [9]}. FDA said their products are unapproved new drugs, whatever the label says ^{[8] [9]}.

The second is products sold as supplements with MK-677 hidden inside. In 2025, FDA lab tests found it in a growth product for children whose label did not list it ^{[10] [11]}.

The third is pharmacies. FDA found websites that say a compounding pharmacy supplies their MK-677. FDA could not tell if any pharmacy still sells it ^[6]. A pharmacy that makes it now is outside the rules, because it is on Category 2 ^{[1] [2]}.

FDA warns that MK-677 may cause heart failure in some people. FDA also says its long-term effects are unknown ^{[1] [10]}.