MK-677
Ibutamoren (oral; not a peptide) · S-tier (Dr. Alex Tatem) · Moderate evidence
An oral pill that raises GH and IGF-1 all day. It builds lean mass and appetite, but it clearly worsens blood sugar.
Dr. Tatem’s take
S-tier for appetite and bulking in his SARMs list, with firm caveats: watch blood sugar, never use it while cutting, and avoid it with heart disease.
Benefits
- Raised lean mass over 2 years in older adults.
- Strong appetite increase, useful for people who can’t eat enough.
- Reversed muscle breakdown during dieting in a short study.
Risks
- Higher fasting glucose and A1C; lower insulin sensitivity.
- Water retention and swelling.
- A hip-fracture trial in frail elderly patients was stopped early over a heart-failure signal.
- Raised prolactin.
Dosing protocols (informational, labeled by evidence)
- Clinical trial / label: RCT – healthy older adults — 25 mg, Oral, Once daily, 12 mo (+12 mo extension)
- Clinical trial / label: Hip-fracture RCT — 25 mg, Oral, Once daily, Planned 24 wk; stopped early
- Community (bro science): Typical gray-market use — 10–25 mg, Oral (often bedtime), Daily, Varies
Status: Not approved. On FDA’s Category 2 “significant safety risk” list (503A and 503B).
Grade and commentary: Dr. Alex Tatem. Watch: SARMs Tier List: Ostarine, RAD-140, MK-677 & LGD Explained by a Doctor, MK-677 Review by a Doctor | Is It Safe or Hype?, MK-677: Muscle Growth or Metabolic Disaster?. Subscribe: @DrAlexTatem.