Read 30 October 2026, every figure sourced and dated. MK-677 has more trial-typed papers than any other unapproved compound in our table, and FDA still lists it in Category 2 for a potential heart-failure risk. More trials is not safer. We cover status, evidence and harms, and nothing about dosing or where to buy.
Whitepill finding
As of 30 October 2026, PubMed types 16 MK-677 papers as clinical trials, more than any other unapproved compound we track, yet FDA's page, current to 22 April 2026, lists ibutamoren mesylate in Category 2 for a potential congestive heart failure risk. A trial count is depth, not safety.
The short version
They sayFDA is fine with it.
FDA lists ibutamoren mesylate in Category 2, citing a potential for congestive heart failure in certain patients. See the receipt
They sayPlenty of trials, so it must be safe.
16 papers typed as trials is the deepest unapproved record in our table. A trial in people recovering from hip fracture was stopped early over a heart failure signal. See the receipt
They sayThis is a new worry.
FDA's table dates the 503B listing to 29 December 2022 and the 503A listing to 29 September 2023. See the receipt
FDA's page on bulk drug substances that may present significant safety risks (content current as of 22 April 2026) lists ibutamoren mesylate in Category 2 for both compounding policies: added for 503B on 29 December 2022 and for 503A on 29 September 2023. Nothing on that page approves it.
FDA's stated reason, in our paraphrase: it poses significant safety risks because of a potential for congestive heart failure in certain patients, and the agency points to a randomized, placebo-controlled trial in people recovering from hip fracture that was stopped early over a heart failure safety signal. Our own walk through what the categories mean is in how FDA's peptide categories work.
FDA's table names the substance only as ibutamoren mesylate. The 2008 Neurology abstract on PubMed states the equivalence itself, calling it "MK-677 (ibutamoren mesylate)", and the 2011 paper's title uses "MK-0677 (ibutamoren mesylate)".
A PubMed search on MK-677 and ibutamoren returns 64 papers. 45 carry PubMed's loose "humans" tag, which is not the same as a human trial.
16 are tagged as a clinical trial or randomized trial, and 4 are tagged as case reports. ClinicalTrials.gov lists 8 interventional studies matching the names; we have not assessed their design or results.
For scale, the next deepest unapproved compound in our table is Melanotan II with 4 trial-typed papers, BPC-157 has 0 (see our BPC-157 check), and semaglutide, a blockbuster approved drug used for scale only, has 344. So MK-677 has the deepest record of its kind here, and it is still in Category 2. That is the point of this page: a long trial list and a safety listing sit side by side.
We opened two abstracts at PubMed and state only their design and population. Here they are side by side.
Both groups are older patients with a disease or injury. Neither describes healthy young adults, and neither tells you what happens in anyone outside its own population.
The trial populations were older, ill patients, and the record cannot tell us how much risk differs for other groups. If you or someone you know has had a bad reaction to any product, report it to FDA MedWatch.
1. A count of tagged trial papers is depth of record, not effect, quality or safety. 2. Open the trial and read why it stopped, if it did. 3. Check the regulator's own page, and the date on it. 4. Ask who the participants were. Results in one group do not transfer to another. 5. Take what you read to a licensed clinician, and report any adverse event to FDA MedWatch.
Trial depth is only one rung. The evidence ladder sets randomized-trial counts for ordinary topics beside attention. MK-677's 16 is deeper than most compounds the scene discusses, but a rung is not a verdict: depth of record tells you that studies were run, and these studies are where the heart-failure signal came from.
PubMed counts come from the published query shown on each linked search (title and abstract terms for the names, plus a publication-type filter where stated), read 30 October 2026; they move as papers are indexed, and the "humans" tag is a loose label.
ClinicalTrials.gov counts are interventional studies matching the same terms, read the same day. The FDA row was read from FDA's page on 30 October 2026, and the two abstracts were opened at PubMed the same day; we state only what each abstract says about design and population.
We found no test data from any tester for MK-677, so this page has no quality grade. Nothing here is medical advice, and the page contains no dosing, protocol or sourcing information by design.
Nothing on FDA's own bulk-substances page approves it. As of that page's content date of 22 April 2026, FDA lists ibutamoren mesylate, the name behind MK-677, in Category 2 for both 503A and 503B compounding, citing a potential for congestive heart failure in certain patients. We read the page on 30 October 2026.
FDA says it poses significant safety risks because of a potential for congestive heart failure in certain patients, and notes a randomized placebo-controlled trial in people recovering from hip fracture that was stopped early over that signal.
No. PubMed has 16 trial-typed papers on it, the most of any unapproved compound in our table, and FDA still lists it in Category 2. A trial count is depth of record (tagged trial papers, not effect or quality). Trials are also where safety signals get found.
As of 30 October 2026, PubMed has 64 papers, 45 tagged human, 16 typed as clinical or randomized trials and 4 as case reports, and ClinicalTrials.gov lists 8 interventional studies. We have not assessed every study's quality.
In the two abstracts we read, the participants were 123 elderly hip-fracture patients (2011) and 563 patients with mild to moderate Alzheimer disease (2008). Neither tells you about healthy people.
To FDA MedWatch, FDA's adverse event reporting program, and tell a licensed clinician. Reports are how a safety record gets built.
MK-677 has 16 trial-typed papers, the deepest record of any unapproved compound in our table, and FDA lists it in Category 2 over a potential for congestive heart failure after a trial was stopped early. More trials is not safer. Nothing here is medical advice; take it to a licensed clinician.