Peptide dossier, updated Nov 1, 2026
Ibutamoren (MK-677)
Ibutamoren mesylate, also called MK-677, MK-0677 and LUM-201. A non-peptide oral drug, covered here because it is sold and discussed with the peptides. A drug taken by mouth that mimics ghrelin and raises growth hormone and IGF-1. It is not a peptide. It has no FDA-approved use. It was developed by Merck and has been studied in older adults, in hip fracture patients and in Alzheimer’s disease; a company called Lumos Pharma now lists a pediatric phase 3 trial of LUM-201. FDA says it poses significant safety risks because of a heart failure signal in a trial.
See all 12 verified records for Ibutamoren (MK-677) on the Records page
In plain terms
Approved for: Nothing from FDA. It is not approved for any use. A pediatric growth hormone deficiency phase 3 trial (LUM-201) is listed as recruiting.
What it is: A pill that mimics ghrelin, the hunger hormone, and raises growth hormone and IGF-1 levels. It is not a peptide.
What it is said to do, and by whom:
- Researchers, 2008 two-year trial in 65 healthy older adults: it raised growth hormone and IGF-1 to young-adult levels and increased fat-free mass versus placebo, with higher fasting glucose and lower insulin sensitivity.
- Researchers, 2011 hip-fracture trial: IGF-1 rose but most functional measures did not improve, and the trial stopped early after a heart failure signal in a few patients.
- FDA: says it poses significant safety risks because of the potential for congestive heart failure in certain patients.
- We did not collect sellers’ claims for this compound.
How strong the evidence is: Human trials exist, which is more than most compounds in this set. They show a hormone effect, a small increase in fat-free mass in healthy older adults, and safety signals: higher blood glucose, weight gain, edema and a heart failure signal in hip-fracture patients. We found no trial showing a clinical benefit.
FDA review
FDA’s safety-risk page (content current Apr 22, 2026) is the one FDA document on ibutamoren that we read.
What the page says
- It lists “Ibutamoren mesylate” in category 2 under both the 503A and 503B interim policies: 503B added Dec 29, 2022 and 503A added Sep 29, 2023.
- It says ibutamoren mesylate poses significant safety risks due to the potential for congestive heart failure in certain patients.
- It says the agency is aware of a randomized, placebo-controlled trial assessing ibutamoren for patients recovering from hip fracture that “was terminated early due to a potential safety signal of congestive heart failure.”
What we did not find
- The page gives no citation. The 2011 hip-fracture paper in the next section says its trial was “terminated early due to a safety signal of congestive heart failure,” which closely matches FDA’s wording, but FDA does not say that is its source.
- We found no FDA briefing document, advisory committee review or press release specific to ibutamoren.
Registered trials
ClinicalTrials.gov returns 8 studies for ibutamoren and MK-0677 as of Nov 1, 2026. We opened the records below. Registry entries are written by sponsors and are not reviewed for scientific merit.
| Registry | Study | Status | What the record says |
|---|---|---|---|
| NCT00074529 | Merck phase 2, Alzheimer’s disease | Completed, 2006 | Sponsor: Merck Sharp & Dohme. No results posted on the registry. A 2008 Neurology paper on an MK-677 Alzheimer’s trial reports no clinical effect on progression; we did not confirm it is this record. Neurology PubMed |
| NCT00128115 | Merck phase 2, sarcopenia in patients after hip fracture | Terminated, Sep 2005 to Aug 2007 | 83 enrolled. The record states no reason for stopping. We did not find a publication tied to it, and it is not the same enrollment as the 123-patient paper in the next section. |
| NCT05364684 | Phase 2, nonalcoholic fatty liver disease (Massachusetts General Hospital) | Completed, Dec 2024 | 12 enrolled. The record lists the drug as LUM-201 (ibutamoren mesylate). Results are posted on the registry; primary outcome is liver fat after 6 months. We did not read the results. |
| NCT06948214 | Phase 3, children with growth hormone deficiency (Lumos Pharma) | Recruiting; started May 20, 2026; est. completion Jan 2028 | 150 planned. Studies LUM-201 versus placebo in children who have not had treatment. The registry names the drug only as LUM-201; the MGH record above links LUM-201 to ibutamoren mesylate. |
We also saw studies from the University of Virginia on kidney disease patients (one completed with results, one withdrawn) and a fibromyalgia study; we did not open them.
Published research
PubMed returns 118 results for ibutamoren, MK-677 and MK-0677 in the title or abstract as of Nov 1, 2026. We read the abstracts of the papers below.
What the papers show
- Healthy older adults, 2008. 65 adults aged 60 to 81, two-year randomized trial of 25 mg daily. Growth hormone and IGF-1 rose to young-adult levels. Fat-free mass rose 1.1 kg versus a 0.5 kg fall on placebo. Visceral and total fat did not differ. Body weight rose 2.7 kg versus 0.8 kg. Fasting glucose rose about 5 mg/dL and insulin sensitivity fell. Common side effects were increased appetite, mild edema and muscle pain. Ann Intern Med PubMed
- Hip fracture, 2011. 123 elderly patients, 25 mg daily for 24 weeks. IGF-1 rose by 51.4 ng/mL. Gait speed improved (p = 0.011) but most functional measures did not. The trial stopped early after a heart failure signal in a limited number of patients, and the authors call the safety profile unfavorable in this population. Arch Gerontol Geriatr PubMed
- Dieting volunteers, 1998. Eight healthy volunteers on a calorie-restricted diet; the paper tests whether it reverses diet-induced protein loss. J Clin Endocrinol Metab PubMed
- Dialysis, 2018. A randomized crossover study: 26 hemodialysis patients enrolled and 22 completed 3 months. The primary outcome, IGF-1, was higher on the drug (geometric mean 1.07-fold). Nephrol Dial Transplant PubMed
- Alzheimer’s disease, 2008. The title reports no clinical effect on disease progression in a randomized trial; we read the title only. Neurology PubMed
Read with care
- The two outcome trials above are small, and the hip-fracture trial ended early, so its efficacy numbers are weak evidence.
- We did not read full text, funding or disclosures. Merck sponsored some of the early work; we did not check each paper.
- Raising IGF-1 is a hormone effect, not a clinical outcome.
Timeline
Newest first. Every entry links to the document it comes from.
- Government or registry record
- Journal
- Oct 30, 2026RegulatoryHHS publishes draft policy pausing enforcement on six peptides; Ibutamoren is not one of them
The draft policy’s appendix names six peptides: BPC-157, epitalon, KPV, MOTS-c, Semax and TB-500. The policy is a draft and not FDA approval. We read the appendix through a text extraction.
- July 23–24, 2026RegulatoryFDA advisory committee meets on seven peptides; Ibutamoren is not among them
The committee recommended six of the seven, all nonbinding. FDA’s notice of the meeting does not list Ibutamoren.
- May 20, 2026RegistryPediatric phase 3 trial of LUM-201 starts, per ClinicalTrials.gov
150 children with growth hormone deficiency planned; estimated completion January 2028.
- Apr 22, 2026RegulatoryFDA’s safety-risk page lists Ibutamoren
FDA lists ibutamoren mesylate as posing significant safety risks due to potential congestive heart failure, citing a hip-fracture trial terminated early.
- Jan 1, 2026Anti-dopingWADA’s 2026 Prohibited List names ibutamoren (MK-677) in S2.2.4
The list names it among GH secretagogues. We read WADA’s own file through a text extraction.
- Sep 29, 2023RegulatoryFDA places ibutamoren mesylate in category 2 under the 503A interim policy
The 503B date was Dec 29, 2022. Dates per FDA’s safety-risk page.
- 2011LiteratureHip-fracture trial stops early after a heart failure signal
123 patients. Published in Arch Gerontol Geriatr.
- 2008LiteratureTwo-year trial in healthy older adults reports more fat-free mass, higher fasting glucose
65 adults. Published in Ann Intern Med.
Still not covered
Left off rather than guessed:
- HHS policy: we read the draft policy appendix through a text extraction, not as the original PDF layout. It names six covered peptides and not ibutamoren.
- FDA review: we found no FDA briefing document or advisory committee evaluation for ibutamoren. FDA’s notice for the July meeting does not name it.
- The trial FDA cites: FDA names a hip-fracture trial but gives no citation. The 2011 paper matches its wording; we have not confirmed it is the one.
- The Merck hip-fracture record (NCT00128115): enrollment differs from the 2011 paper, so it may be a different trial or an earlier stage. We did not resolve this.
- LUM-201 and ibutamoren: we rely on the MGH record to treat them as the same drug. We did not read Lumos’s own documents.
- Warning letters: we found none that name ibutamoren. Absence is not proven.
- Patents and SEC filings: not researched for this dossier.
- Seller claims and independent lab reports: how gray-market product is marketed versus what testing finds. We have not collected testing data.
- Unread items: full text of most papers; EU and other non-US regulators and registries; WADA lists for years other than 2026; FDA warning letters beyond those listed, which rest on web searches.