Ibutamoren (MK-677)
Active Substance: Ibutamoren
Description
Ibutamoren, also known as MK-677 or Nutrobal, is a growth hormone secretagogue. This means it is a compound that stimulates the pituitary gland to release growth hormone (GH). It works by mimicking the action of the hormone ghrelin, which is responsible for stimulating GH release and regulating appetite. Unlike exogenous GH injections, which introduce synthetic growth hormone directly into the body, ibutamoren works by increasing the body's own natural production of GH and insulin-like growth factor 1 (IGF-1).
Side Effects and Benefits
Benefits:
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Muscle Growth and Strength: By increasing levels of GH and IGF-1, ibutamoren can promote muscle growth, enhance recovery, and improve strength.
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Improved Sleep: Users often report better sleep quality and increased REM sleep.
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Bone Density: Studies have shown it can increase bone mineral density, making it a potential therapy for conditions like osteoporosis.
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Fat Loss: It has been reported to boost metabolism and help with fat loss, contributing to a leaner body composition.
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Skin, Hair, and Nails: Some users note improvements in the health and appearance of their skin, hair, and nails due to the elevated GH levels.
Side Effects:
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Increased Appetite: Due to its ghrelin-mimicking properties, one of the most common side effects is a significant increase in appetite, which can lead to weight gain.
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Water Retention/Edema: Users may experience fluid retention and swelling, especially in the extremities.
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Insulin Resistance: Ibutamoren can increase fasting blood glucose levels and decrease insulin sensitivity, which raises the risk of hyperglycemia and, with long-term use, the development of type 2 diabetes.
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Numbness and Joint/Muscle Pain: Some users have reported temporary numbness or tingling in the extremities and joint or muscle pain.
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Potential Cardiovascular Risks: A clinical trial was stopped early due to concerns that ibutamoren may increase the risk of congestive heart failure in certain patients.
Pros and Cons
Pros:
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Oral Administration: It is taken orally as a powder, tablet, or liquid, which is a significant advantage over injectable GH peptides.
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Stimulates Natural GH Production: It works with the body's own systems to increase GH, rather than introducing a synthetic hormone.
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Non-Hormonal: It does not directly affect testosterone or other androgenic hormones.
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Legal Status (for research): It is often sold as a "research chemical," which makes it more accessible, though its use for human consumption is illegal and unregulated in many places.
Cons:
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Unapproved for Human Use: Ibutamoren is an investigational drug and is not approved by regulatory bodies like the FDA for human use. Its long-term safety profile is not fully established.
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Serious Health Risks: The potential for serious side effects, including increased risk of diabetes and heart failure, is a major concern.
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Prohibited in Sport: It is on the World Anti-Doping Agency (WADA) Prohibited List and is banned in all legitimate forms of competition.
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Variable Product Quality: As it is sold on the black market, the purity, potency, and safety of products can be highly inconsistent.
Dosage and Frequency
Information on dosage and frequency is based on anecdotal and research data, not medical guidelines, as the substance is not approved for human consumption. Typical dosages range from 10 to 25 mg per day, with some users taking up to 50 mg. Frequency is generally once a day due to its long-lasting effects. It is often recommended to be taken before bed to coincide with the body's natural GH release cycle. Cycling the substance is also commonly suggested to prevent tolerance buildup.
Half-Life and Detection Time
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Half-Life: The elimination half-life of ibutamoren is reported to be around 4-6 hours in some animal studies. However, its effects, particularly the elevation of IGF-1 levels, are much longer-lasting, with a single oral dose sustaining elevated IGF-1 for up to 24 hours.
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Detection Time: Due to its status as a prohibited substance in sports, its detection time is a key concern for athletes. Ibutamoren can be detected in urine for several days to a few weeks, and its metabolites can be present for a longer duration.
Steroidogenic, Progestogenic, and Prolactin Effects
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Steroidogenic and Progestogenic: Ibutamoren is not a steroid and does not have direct steroidogenic or progestogenic effects. It does not act on androgen or progesterone receptors. It does not cause a shutdown of the body's natural testosterone production, unlike anabolic steroids.
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Prolactin: While ibutamoren does not directly affect prolactin levels in the same way as some other compounds, there is some research on other growth hormone secretagogues (like sermorelin) that suggests a small, acute rise in prolactin levels. The effects of ibutamoren on prolactin are not as well-documented, but are not considered a primary effect.
Anabolic Androgenic Ratio
Ibutamoren (MK-677) does not have an anabolic-androgenic ratio. This ratio is a metric used to compare the anabolic (muscle-building) effects of a compound to its androgenic (masculinizing) effects. The ratio is primarily applicable to anabolic-androgenic steroids (AAS). Since ibutamoren is not a steroid and does not act on androgen receptors, this ratio is irrelevant to its pharmacological profile. It has anabolic effects through GH and IGF-1, but no significant androgenic effects.
Pharmacological Properties
Half Life
1 days
Active Dose
100%
Detection
5.00 days
Concentration
10 mg/cap
Anabolic/Androgenic Profile
Usage Effectiveness
Activity Profile
Estrogenic
None
Progestanic
None
Water Retention
None
Aromatization
No
Benefits
Dosage Recommendations
Beginner
10-20 mg/week
Intermediate
20-30 mg/week
Advanced
30-40 mg/week
Evidence-based planning resources
Dive deeper into Ibutamoren (MK-677) cycle design, stacking options, and harm-reduction checklists available inside Anabolic Planner.
- Ibutamoren (MK-677) compound database overviewCompare Ibutamoren (MK-677) with other sarm agents in the structured compound index.
- Ibutamoren (MK-677) stack and cycle templatesReview evidence-based cycle outlines, dose progressions, and PCT pairings that incorporate Ibutamoren (MK-677).
- Harm-reduction guide for Ibutamoren (MK-677)Refresh safety monitoring, lab work, and countermeasure strategies tailored for Ibutamoren (MK-677) protocols.
Peer-reviewed reference material
Validate mechanisms, contraindications, and regulatory guidance for Ibutamoren (MK-677) with trusted clinical databases.
- Ibutamoren clinical research on PubMedSearch peer-reviewed human and veterinary studies discussing efficacy, endocrine impact, and contraindications.
- Ibutamoren pharmacology via Drug Information PortalReview mechanisms, synonyms, regulatory status, and toxicology summaries from the U.S. National Library of Medicine.
Side Effects
Common
Rare
Severe
Safety Information
Liver Toxicity
Low
Kidney Toxicity
Low
Cardiovascular Risk
Low
Disclaimer: This information is for educational purposes only. Always consult with a qualified healthcare professional before using any compounds.