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Research / Unapproved

MK-677 (Ibutamoren): Research Status and Trial Data

Molecular formulaC28H40N4O8S2
Molecular weight624.8 g/mol
Registered trials8
PubChem CID6450830

What MK-677 is

MK-677, also known as ibutamoren, is a synthetic compound with the molecular formula C28H40N4O8S2 and a molecular weight of about 624.8 g/mol (PubChem CID 6450830). It has no FDA-approved label, no approved brand name, and no approved indication. Any use outside of registered clinical research falls outside its current regulatory status.

Trial footprint

Eight trials involving MK-677 are registered. The available sample spans different research contexts and outcomes. One phase 2 trial examined an oral growth hormone drug for fibromyalgia and is listed as completed. A separate phase 2 trial looking at the compound's effect on lean body mass in people with advanced chronic kidney disease was withdrawn. A related phase 3 program for a growth hormone deficiency treatment in children is currently recruiting, though it is listed under a different compound name (LUM-201) rather than MK-677 itself. These records show a mix of completed, withdrawn, and ongoing research rather than an established, approved therapeutic path.

FAQ

Is MK-677 FDA-approved?
No. MK-677 (ibutamoren) has no FDA-approved label, no approved brand name, and no approved medical indication. It exists only as a research compound at this time.
What is MK-677 used for in research?
Registered trials have studied related compounds in contexts such as fibromyalgia and lean body mass in chronic kidney disease, with one trial completed and another withdrawn. These studies do not establish approved uses or confirmed benefits.
How many clinical trials involve MK-677?
There are 8 registered trials associated with the compound. They vary in status, including completed, withdrawn, and recruiting studies.
What is the chemical identity of MK-677?
MK-677 has the molecular formula C28H40N4O8S2 and a molecular weight of approximately 624.8 g/mol. It is catalogued under PubChem CID 6450830.
Does MK-677 have known side effects?
No adverse event report data is available for this compound in the dataset reviewed. The absence of data here does not mean the compound is free of risk.
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Sources: PubChem ClinicalTrials.gov

Updated 2026-11-07