MK-677 — Safety, Research, Risks & Legal Status

Not medical advice. MK-677 is discussed here for informational and harm-reduction purposes only. We do not endorse use, and any dosing context is informational, not a protocol.

Also known as	ibutamoren, MK0677, L-163191, oratrope
Category	SARM
merck_developer	Developed by Merck & Co. as an oral GH secretagogue for muscle wasting
ghrelin_mimic	Acts as a synthetic ghrelin analog at the ghrelin receptor
oral_advantage	Among the first oral growth-hormone secretagogues, unlike peptide alternatives
US legal status	MK-677 is not approved by the FDA for any use, and it is illegal to market or sell it as a dietary supplement. The FDA has warned that products in this category are associated with serious risks, and MK-677 is sold as a research chemical not for human consumption. It is prohibited at all times in sport under the WADA list.

What is MK-677?

MK-677 (ibutamoren) is a growth-hormone secretagogue, not technically a SARM, but it is commonly grouped and sold with them. It stimulates the body to release more growth hormone and IGF-1.

How it works

MK-677 is an oral, non-peptide growth-hormone secretagogue receptor (GHSR) agonist that mimics ghrelin and stimulates the pituitary to release growth hormone and subsequently IGF-1 from the liver. It crosses the blood-brain barrier and acts centrally at the ghrelin receptor. The result is increased pulsatile GH secretion without affecting cortisol or ACTH.

Background & history

MK-677 (ibutamoren) was developed by Merck & Co. as an oral growth-hormone secretagogue for muscle wasting, osteoporosis, and age-related dysfunction. It advanced to Phase II clinical trials in older adults and patients with cachexia. Development was discontinued before FDA approval, though the compound remains marketed illegally in research-chemical channels.

What the research says

Research suggests MK-677 raises growth hormone and IGF-1 levels and was studied in trials for conditions like muscle wasting and older adults. Studies report side effects such as water retention, increased appetite, and impaired insulin sensitivity, and it was not approved for these uses.

Reported effects

Reported increases in growth hormone and IGF-1 levels
Studied increases in appetite and food intake
Reported improvements in sleep by some users
Studied effects on lean mass and water retention
Reported increases in growth-hormone pulsatility
Studied effects on bone turnover and density markers

Dosing & administration (informational)

In published clinical trials, oral doses of 10-25 mg once daily were studied for 8-16 weeks in healthy and patient populations. Studies demonstrated effects on GH and IGF-1 at these doses, along with side effects like hunger and water retention. No established safe dose for long-term use exists outside clinical trial contexts.

This is general research/context information, not medical advice or a recommended protocol.

Safety & side effects

Reported to cause water retention and edema by raising GH and IGF-1
Reported to increase appetite, which can drive unwanted weight gain
Studies report it can raise blood sugar and reduce insulin sensitivity, a concern for diabetes risk
Elevated IGF-1 is a theoretical concern for anyone with an active or prior cancer since IGF-1 is a growth signal
Prohibited at all times in sport under the WADA list
May cause joint pain or carpal tunnel-type symptoms in some users

Drug & supplement interactions

May interact with glucose-controlling medications given effects on insulin sensitivity
Potential additive effects if combined with other growth-hormone-stimulating compounds
Possible interactions with thyroid medications given effects on metabolic rate
Risk of amplified water retention if combined with other compounds affecting fluid balance
Limited data on interactions with cardiovascular medications given theoretical effects on growth-hormone-dependent tissues

Who should avoid it

Avoid in anyone with diabetes or at high risk given reports of insulin resistance and hyperglycemia
Avoid if there is personal or family history of cancer, given IGF-1 growth-signal concerns
Avoid in those with pituitary or growth-hormone-axis disorders without specialist oversight
Avoid if prone to water retention or at risk for congestive heart failure
Avoid if tested in sport or under workplace drug-screening requirements

How it is commonly combined

MK-677 is sometimes combined with SARMs or other compounds in unregulated communities for purported synergistic muscle gains. However, such combinations multiply metabolic stress, hormonal disruption, and unknown drug interactions. No evidence supports such stacks and all multi-compound use substantially increases risk.

Legal & regulatory. MK-677 is not approved by the FDA for any use, and it is illegal to market or sell it as a dietary supplement. The FDA has warned that products in this category are associated with serious risks, and MK-677 is sold as a research chemical not for human consumption. It is prohibited at all times in sport under the WADA list.

Quality & harm reduction

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Lab testing & harm-reduction tools

If you are going to research a compound, verifying identity and purity is the single most protective step. Independent analytical testing and sterile-handling supplies reduce risk.

Compare testing options

Frequently asked questions

Is MK-677 a SARM?

No. It is a growth-hormone secretagogue that raises GH and IGF-1, but it is commonly marketed and sold alongside SARMs.

Does MK-677 affect blood sugar?

Studies report it can raise blood sugar and reduce insulin sensitivity, which is a concern especially for people at risk of diabetes.

What dose is safe?

We do not provide human dosing guidance. MK-677 is unapproved and any use should involve a qualified clinician.

What are the water-retention effects?

Elevated growth hormone causes fluid retention and edema; the degree varies but can be significant and uncomfortable for some users.

Can MK-677 increase cancer risk?

Elevated IGF-1 is a growth signal and is theoretically concerning in cancer survivors or those at high risk, but clinical data are limited.

References & further reading

PubMed: MK-677 ibutamoren growth-hormone secretagogue clinical trial
PubMed: ibutamoren IGF-1 insulin sensitivity glucose metabolism
FDA warning on unapproved growth-promoting and muscle-building compounds
WADA Prohibited List: growth-hormone secretagogues and related peptides
ClinicalTrials.gov: MK-677 muscle wasting older adults cachexia