What is it?
What it is
5Ibutamoren, commonly sold as MK-677, is an oral non-peptide ghrelin-receptor agonist that stimulates growth hormone release and increases IGF-1. It is not a vitamin, amino acid, herb, or conventional dietary supplement ingredient in the practical buyer sense.
Common marketplace name
1Often sold as MK-677 or ibutamoren capsules, including by vendors that also sell SARMs or research chemicals.
Research-code variant
7Several clinical papers use MK-0677 for ibutamoren mesylate.
Healthy-user claims are the weak link
5The visible product market often implies rest, recovery, muscle, or anti-aging benefits. Clinical data support hormone-marker changes more strongly than real-world improvements in strength, cognition, function, or long-term health.
Names, aliases and forms
Mechanisms of action
Ghrelin-receptor agonism
5Ibutamoren mimics ghrelin-like signaling at the growth-hormone secretagogue receptor, increasing pulsatile growth hormone secretion and downstream IGF-1 in controlled trials.
Metabolic downstream effects
8In an eight-week trial of otherwise healthy obese men, oral MK-677 impaired glucose tolerance even though fasting glucose and insulin did not change. A normal fasting measurement therefore does not establish unchanged glucose handling.
Potential effects and evidence map
Human trials consistently show increased growth hormone and IGF-1, a hormone involved in growth signaling. These laboratory changes have not established a useful nootropic effect: a large Alzheimer trial found no clinical benefit, and a healthy older-adult trial found no strength or functional improvement despite increased fat-free mass. Evidence grade C reflects this limited transfer to healthy buyers, rather than uncertainty that the compound affects hormones.
Older-adult trials show GH/IGF-1 and some lean-mass signals, but strength, function, and recovery outcomes are mixed or mostly unimproved.
A large Alzheimer trial increased IGF-1 but did not slow clinical progression, so cognition and memory claims are weak.
Typical dosages and timing
Several adult trials used 25 mg/day. That clinical-study context should not be read as a general safe dose for unsupervised use.
Timing & effect horizon
The healthy older-adult trial assessed its primary outcomes after 12 months, with exploratory follow-up to 2 years. This is a study window, not a recommended cycle or a duration of cognitive benefit. The reviewed sources do not establish a useful nootropic onset, acute benefit duration or a verified plasma The time for blood levels to fall by half during the final elimination phase.Source for this comparison.
Safety, side effects and risk profile
Ibutamoren is explicitly prohibited in sport under the WADA 2026 list; anti-doping status is separate from retail availability.
Human trials show meaningful GH/IGF-1 target engagement plus glucose, insulin-sensitivity and cortisol signals, so this is endocrine-active rather than benign wellness support.
FDA highlights a congestive-heart-failure safety signal from a hip-fracture ibutamoren trial, and edema/fluid-retention signals are clinically relevant.
Increased appetite was frequent in the older-adult study and generally subsided over several months; this is a tolerability concern, not evidence of gastrointestinal injury.
The strongest evidence shows hormone-marker movement, while cognition, healthy aging, recovery, and performance outcomes remain limited, mixed, or negative.
In a healthy older-adult trial, MK-677 increased fasting glucose, decreased insulin sensitivity, increased body weight, and commonly caused increased appetite plus transient mild lower-extremity edema and muscle pain.
A trial in older adults recovering from hip fracture stopped early after a congestive-heart-failure signal. FDA identifies this as a serious risk in certain patients; it is not an estimate of the risk in healthy young users.
Australia's TGA found undeclared metandienone in Pharmatech MK-677 capsules in June 2026. This finding is specific to that product and does not establish adulteration in the offers displayed here.
Legal and regulatory status
As of 15 October 2026, the U.S. FDA lists ibutamoren mesylate among compounding substances with significant safety concerns, citing potential heart failure in certain patients. U.S. OPSS also identifies MK-677 as an unapproved drug, not a lawful dietary-supplement ingredient. This is U.S. context, not a worldwide legal ruling.
As of 15 October 2026, WADA's effective 2026 list names ibutamoren under growth-hormone secretagogues prohibited in and out of competition. This applies to sport governed by that code; retail availability does not change eligibility.
As of 15 October 2026, TGA reports no ibutamoren product approved for supply in Australia. Its 4 June 2026 alert identified undeclared metandienone in Pharmatech MK-677 capsules. Other countries have their own rules; this alert is not proof that all MK-677 products are adulterated.
Practical buying and quality notes
- Compare capsule strength and total labeled ingredient amount before comparing unit prices: equal capsule counts do not imply equal contents. Check whether milligrams refer to ibutamoren or its mesylate salt. The current catalog includes inconsistent duplicate price records; verify package price, currency and quantity at the merchant before using any displayed minimum. Shipping and discounts can change the final cost.
- A capsule count and milligram claim are not enough. Prefer lot-specific third-party identity testing, impurity testing, and a seller that does not frame MK-677 as a harmless dietary supplement.4
- Hormone markers and fat-free mass are not interchangeable with strength, performance or healthy longevity. In the controlled older-adult study, additional fat-free mass did not produce improved strength or function. A product promise of those outcomes goes beyond that evidence.5
FAQ
Is there an evidence-based MK-677 cycle?
5No safe self-directed cycle has been established by the cited trials. A trial observation window describes when researchers measured outcomes; it does not establish a recommended length of use or a safe break between cycles.
Is Ibutamoren the same as a SARM?
2No. Ibutamoren is a growth-hormone secretagogue, not a selective androgen receptor modulator. It is still often sold beside SARMs and remains prohibited in sport because of its endocrine performance-enhancing pathway.
Is MK-677 a nootropic?
6Not in the evidence-first sense. It changes GH/IGF-1 markers, but human cognition evidence is weak, and a large Alzheimer trial did not show clinical benefit despite IGF-1 increases.
Does capsule strength establish a safe dose?
5No. Per-capsule strength describes a product, not a validated safe daily intake. A label also needs to distinguish the mesylate salt from the active compound; retail naming alone cannot resolve that difference.
What about pregnancy or combining MK-677 with medicines?
1The cited adult trials do not establish safety during pregnancy or breastfeeding, or safe combinations with medicines and other performance-enhancing compounds. These gaps do not establish a specific interaction, but the existing glucose and fluid-retention signals make an assumption of safety inappropriate.
References
- Operation Supplement Safety (OPSS). Performance Enhancing Substance: MK-677 (Ibutamoren).
- World Anti-Doping Agency. The 2026 Prohibited List: International Standard.
- U.S. FDA. Ibutamoren mesylate safety-risk listing for compounding.
- Therapeutic Goods Administration. Unapproved ibutamoren capsules (MK-677) found to contain undisclosed anabolic steroid.
- Nass R, Pezzoli SS, Oliveri MC, Patrie JT, et al. Effects of an oral ghrelin mimetic on body composition and clinical outcomes in healthy older adults: a randomized trial. Ann Intern Med. 2008;149(9):601-611.
- Sevigny JJ, Ryan JM, van Dyck CH, Peng Y, et al. Growth hormone secretagogue MK-677: no clinical effect on AD progression in a randomized trial. Neurology. 2008;71(21):1702-1708.
- Adunsky A, Chandler J, Heyden N, Lutkiewicz J, et al. MK-0677 (ibutamoren mesylate) in patients recovering from hip fracture: a multicenter, randomized, placebo-controlled phase IIb study. Arch Gerontol Geriatr. 2011;53(2):183-189.
- Svensson J, et al. Two-month treatment of obese subjects with the oral growth hormone secretagogue MK-677 increases GH secretion, fat-free mass, and energy expenditure. J Clin Endocrinol Metab. 1998;83(2):362-369.