As of September 2026, the FDA and the EMA have not approved MK-677. Its development for frailty and Alzheimer's disease was stopped after trials found limited benefit and safety concerns. WADA bans it in sport. Bodybuilders and biohackers use it, based on small trials. You cannot tell from the outside what a product sold as MK-677 holds.
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What is MK-677?
MK-677, also called ibutamoren, is a small molecule and not a peptide. Merck developed it in the 1990s as a drug that prompts the pituitary gland to release more growth hormone. It was tested for frailty in older people, growth hormone deficiency, hip-fracture recovery and Alzheimer's disease, and none of those programs led to FDA or EMA approval.
Does MK-677 work?
In trials, it modestly raised fat-free mass in healthy older adults and showed no benefit on the progression of Alzheimer's disease. No trial has shown a favorable long-term balance of risk and benefit in any group.
What we found. 3 completed randomized trials counted on the record. 3 study rows listed below, and the record labels one of them, the Alzheimer's trial, as randomized.
| Study | Tested in | Status | What it shows |
|---|---|---|---|
| Sleep trial, 1997 | People | Published in 1997. Small | Slow-wave sleep improved with prolonged treatment, and IGF-1 rose |
| Body composition trial in healthy older adults | People | Published | Fat-free mass rose modestly. Fasting blood sugar and markers of insulin resistance rose too |
| Alzheimer's disease trial | People | Published. Randomized | No benefit for thinking or everyday function, though IGF-1 rose. The program was stopped |
Is MK-677 safe?
Nobody knows whether long-term use is safe. Trials in healthy older adults found raised blood sugar and fluid retention. Development for frailty and Alzheimer's disease was stopped after trials found limited benefit and safety concerns. People who use it now rely on small trials, with no long-term safety data behind them. That is the drug Merck developed. What is sold under the name today is covered below.
Is MK-677 legal?
- United States
- Not approved by the FDA. Development for growth hormone deficiency, frailty and Alzheimer's disease was stopped after negative or limited trials.
- European Union
- No EMA marketing authorisation.
- Sport
- Banned in sport. The record names no class and no timing.
Not medical advice. Approval and sport status as of . Medical disclaimer
What is in a product sold as MK-677?
The record says bodybuilders and biohackers use MK-677 hoping to gain muscle or improve sleep. It does not say how the product is sold or in what form, and it lists no test of anything sold under the name. A "research use only" label guarantees nothing about purity. A certificate of analysis counts only if it names your lot number, a lab with no stake in the result, and the method used. Purity and identity are separate tests.
Three questions to ask the seller:
- Which lot number is this certificate for?
- Who ran the test, and are they independent of you?
- Does the report confirm identity by mass spectrometry, or purity alone?
What don't we know?
- Whether long-term use is safe in any group. No trial has shown a favorable long-term balance of risk and benefit.
- Whether the sleep finding from one small 1997 trial holds up. The record lists no larger sleep trial.
- What raised blood sugar and fluid retention lead to over the long term.
- What is in any vial or other product sold as MK-677.
The other side
The record says bodybuilders and biohackers use MK-677 hoping to gain muscle or improve sleep. That hope rests on small trials. A personal result cannot fill in what those trials left out: long-term safety, and what the product in hand contained.
What would change this record?
- A new randomized controlled trial that is long enough and large enough, with a favorable result on safety and benefit.
- A submission to the FDA or the EMA after such a trial. The record says no such trial is under way.
Three questions to ask next
- What does 'research use only' actually mean?
- How can you tell if a peptide vendor is legitimate?
- How do you read a certificate of analysis?
Ask better questions.
More questions about MK-677
Is MK-677 a peptide?
- No. The record describes it as a small organic molecule, not a peptide.
Is MK-677 the same as ibutamoren?
- Yes. The record is filed under ibutamoren and lists MK-677 and MK-0677 as other names.
Is MK-677 approved by the FDA?
- No. It has never been approved by the FDA or the EMA. Development was stopped after negative or limited trials.
Is MK-677 banned in sport?
- Yes. The record says WADA prohibits it in sport. It names no class and no timing.
Did MK-677 help in Alzheimer's disease?
- No. A published randomized trial found no benefit on the progression of the disease. The program was stopped.
THE PEPTIDE TABLE
RECORD · IBUTAMOREN
- Checked
- 22 SEP 2026
- Sources read
- 3
- Approved?
- NO
- Sport (WADA)
- BANNED
- COMPLETED RANDOMIZED TRIALS
- 3
- GRADE
- B
Ask better questions.
thepeptidetable.com/table/mk-677
The record on one slip. Save it as a picture and send it to whoever asked you about MK-677.
Record checked on . Each source shows the date it was checked.
In the same group
- IpamorelinGrade C2 completed randomized trials
- SermorelinGrade B1 completed randomized trial
- Tesamorelin (Egrifta)Grade A4+ completed randomized trials
- CJC-1295Grade C1 completed randomized trial
- GHRP-2 (pralmorelin)Grade C1 completed randomized trial
- GHRP-6Grade C4+ completed randomized trials