Source comparison
MK-677 Safe Side Effects: Comparison Across Growth Hormone Pathways
Growth Hormone Elevation Sustained 24-hour elevation; IGF-1 increases 40–60% at 25mg daily Pulsatile release mimicking natural GH rhythm; moderate IGF-1 increase Direct replacement; IGF-1 increase proportional to dose MK-677 produces the highest sustained GH b
This comparison does not assign a generated winner or score.
- Growth Hormone Elevation
- Sustained 24-hour elevation; IGF-1 increases 40–60% at 25mg daily
- Pulsatile release mimicking natural GH rhythm; moderate IGF-1 increase
- Direct replacement; IGF-1 increase proportional to dose
- MK-677 produces the highest sustained GH but also the most metabolic disruption
- Insulin Sensitivity Impact
- 15–34% reduction in insulin sensitivity over 12–16 weeks
- Minimal impact in clinical trials; glucose typically stable
- Moderate reduction; dose-dependent; reversible with discontinuation
- MK-677 carries the highest insulin resistance risk of all GH pathways
- Water Retention (Edema)
- 2–4 kg fluid gain in first 4 weeks; aldosterone-mediated
- Mild; typically <1 kg; transient
- Moderate; 1–2 kg; dose-dependent
- MK-677 causes the most pronounced and sustained edema
- Appetite Dysregulation
- Universal; 60–90% ghrelin increase; persists throughout use
- Minimal to absent; GHRP-2/6 can increase appetite transiently
- Mild increase; indirect via IGF-1
- Only MK-677 produces clinically significant appetite stimulation
- Cortisol Elevation
- 15–25% increase in morning cortisol; sustained
- Minimal; follows natural cortisol rhythm
- Suppresses endogenous cortisol; long-term use disrupts HPA axis
- MK-677 elevates cortisol without the feedback suppression seen with exogenous GH
- Long-Term Safety Data
- Limited; longest trial is 2 years in elderly; no data in healthy adults beyond 16 weeks
- Moderate; multiple Phase II/III trials in healthy and clinical populations
- Extensive; decades of clinical use; well-characterised risk profile
- MK-677 has the least long-term human safety data of the three