Ibutamoren (MK-677)
Also known as MK-677, Ibutamoren mesylate
An orally active growth-hormone secretagogue with real human trial data, never FDA-approved.
Medically reviewed by Dr. Jonathan Snipes, MD
Reviewed for clinical accuracy · Last reviewed July 22, 2026 · Review policy
Quick answer
Ibutamoren (MK-677) is an orally active growth-hormone secretagogue that reliably raises growth hormone and IGF-1 in humans. It has real clinical trial data but was never FDA-approved, is prohibited in sport, and can raise blood sugar and appetite.
- Drug class
- Oral ghrelin mimetic / GH secretagogue
- FDA status
- Not approved (investigational)
- Route
- Oral
- Evidence grade
- C (Emerging Human Data)
- Banned in sport
- Yes (WADA)
Key takeaways
- →Ibutamoren is unusual among these compounds in being orally active and having genuine human trial data.
- →It reliably increases growth hormone and IGF-1, and has been studied for body composition and bone density.
- →It was investigated by a major pharma program but never FDA-approved.
- →Notable downsides: increased appetite, water retention, and raised blood glucose / insulin resistance. It is banned in sport.
Ibutamoren, better known by its development code MK-677, is one of the more genuinely studied compounds in the growth-hormone space. It is orally active, which is rare for this category, and it has real human trial data showing it raises growth hormone and IGF-1. Despite that, it was never brought to market, and its metabolic side effects are a meaningful part of the picture.
How Ibutamoren (MK-677) works
Ibutamoren mimics ghrelin and activates the growth-hormone secretagogue receptor, stimulating the pituitary to release growth hormone and, downstream, raising IGF-1. Because it is a small orally-available molecule rather than an injected peptide, it produces a sustained increase in GH signaling that has been documented in controlled human studies.
What the evidence shows, by use
Each use is graded on the same A-E scale, based on human-trial quality rather than popularity.
Raising GH / IGF-1 and body composition
CEmerging Human DataHuman trials consistently show increased GH and IGF-1 and some effects on lean mass; long-term outcome and safety data is more limited.
Bone density / older adults
CEmerging Human DataStudied in older adults with mixed clinical relevance; not an approved treatment.
Dosing
Ibutamoren is not an approved drug, so there is no official dose. It has been studied at defined oral doses in trials, but products sold to consumers are unregulated. Because it raises blood glucose and can worsen insulin sensitivity, anyone considering it should involve a licensed clinician and monitoring, not self-dose from research-chemical sources.
Side effects
- •Increased appetite · Common
- •Water retention / edema · Common
- •Lethargy or fatigue · Less common
- •Raised blood glucose / insulin resistance · Less common
Legal & regulatory status
Ibutamoren (MK-677) is not FDA-approved and is prohibited in sport. It is sold as a research chemical, outside the regulated supply chain.
Is Ibutamoren (MK-677)legal? Full regulatory status →Where to get it: TeleRanked independently ranks the telehealth providers that offer clinician-prescribed peptides. See our Peptide Therapy rankings. We rank providers, we do not sell compounds, and rankings are never for sale.
Frequently asked questions
Does ibutamoren (MK-677) actually raise growth hormone?+
Yes. Human trials consistently show it increases growth hormone and IGF-1. The open questions are about long-term benefit and safety, not whether it affects GH.
Is MK-677 a steroid?+
No. It is a growth-hormone secretagogue that stimulates the body's own GH release; it is not an anabolic steroid.
Is ibutamoren safe?+
Its short-term effects are documented, but long-term safety is not established, and it can raise blood glucose and reduce insulin sensitivity, so it warrants clinician oversight and monitoring.
How we grade evidence
Grade C: Emerging Human Data. Early or small human studies exist; results are preliminary and not yet confirmed at scale. Our A-E scale reflects the strength of human evidence, not how popular a compound is.
Sources
- 1.Compounding and the FDA: Questions and Answers · U.S. Food & Drug Administration
- 2.WADA Prohibited List · World Anti-Doping Agency