MK-677
Also known as: Ibutamoren · MK677 · L-163 · 191 · Nutrabol
MK-677 is an orally active, non-peptidic agonist of the ghrelin receptor (GHS-R1a). Unlike peptide GHRPs which require injection, MK-677 is highly orally bioavailable and has a long half-life (~24 hours) allowing once-daily oral dosing. It stimulates pulsatile GH release from...
What It Is
MK-677 is an orally active, non-peptidic agonist of the ghrelin receptor (GHS-R1a). Unlike peptide GHRPs which require injection, MK-677 is highly orally bioavailable and has a long half-life (~24 hours) allowing once-daily oral dosing. It stimulates pulsatile GH release from the pituitary and raises IGF-1 levels significantly (30-60% over baseline). It also moderately stimulates appetite via GHS-R1a. It does not meaningfully elevate cortisol or ACTH at standard doses - more selective in this regard than GHRP-2 or GHRP-6. Long-term use produces sustained IGF-1 elevation. Originally studied for muscle wasting disorders and frailty in elderly patients.
Supplies Needed
Oral capsule administration
Reconstitution if injectable
Subcutaneous administration
Storage
Store at room temperature in original packaging for oral capsules/liquid. Powder at -20C.
Refrigerate at 2-8C; use within 30 days.
This information is provided for educational and research purposes only. Not approved for human consumption by the FDA or any regulatory body. Always consult a qualified medical professional.
Dosing Protocols
Timing: Before bed (to coincide with natural nocturnal GH pulse; also manages hunger). Start at 10 mg to assess hunger and water retention; most benefits seen at 15-25 mg
↓ Apply these values to the reconstitution calculatorTiming: Before bed. 25 mg is the most studied dose; IGF-1 elevation plateau at ~25 mg
↓ Apply these values to the reconstitution calculatorTiming: Before bed. Long-term use studied up to 2 years in clinical trials; monitor IGF-1, blood glucose, and IGF-1 levels; beneficial for anti-aging and muscle preservation
↓ Apply these values to the reconstitution calculatorWeekly Timeline
| Week | Expected Effects |
|---|---|
| Week 1 | Significantly improved sleep depth and vivid dreams; noticeable hunger increase; mild water retention |
| Week 2 | IGF-1 beginning to rise; improved recovery; continued water retention |
| Week 4 | Sustained IGF-1 elevation; improved muscle fullness; body composition beginning to improve |
| Week 8 | Significant lean mass gains; improved skin quality; notable anti-aging effects with long-term use |
| Week 12 | Maximum IGF-1 elevation and body composition improvements; improved bone density markers |
Reconstitution Calculator
1 unit on U-100 syringe = 0.01 mL · Always label your vial after reconstitution
Injection Technique & Reconstitution
- MK-677 is typically available as oral capsules or liquid for oral use - no reconstitution required
- If in lyophilized powder form for injection: Remove flip-top cap
- Swab rubber stopper with alcohol swab
- Draw 1 mL bacteriostatic water
- Inject slowly down the vial wall and swirl gently
- Label with date; refrigerate at 2-8C
Use our free peptide dosage calculator to get the exact syringe units for your vial size and dose.
Mechanism of Action
MK-677 is an orally active, non-peptidic agonist of the ghrelin receptor (GHS-R1a). Unlike peptide GHRPs which require injection, MK-677 is highly orally bioavailable and has a long half-life (~24 hours) allowing once-daily oral dosing. It stimulates pulsatile GH release from the pituitary and raises IGF-1 levels significantly (30-60% over baseline). It also moderately stimulates appetite via GHS-R1a. It does not meaningfully elevate cortisol or ACTH at standard doses - more selective in this regard than GHRP-2 or GHRP-6. Long-term use produces sustained IGF-1 elevation. Originally studied for muscle wasting disorders and frailty in elderly patients.
Key Research Papers
Demonstrated that oral MK-677 significantly increased GH pulsatility and IGF-1 levels to those of healthy young adults in elderly subjects, with sustained effects over 2 years.
View on PubMed →Stacks Well With
Oral MK-677 for sustained 24-hour GH/IGF-1 elevation combined with Ipamorelin injections for acute pulsatile GH release provides comprehensive GH optimization.
MK-677 GH elevation for systemic anabolism and recovery combined with BPC-157 for local tissue repair and gut health.
Frequently Asked Questions
MK-677 is an orally active ghrelin receptor agonist that stimulates pulsatile GH release and raises IGF-1 by 30-60%. Unlike injectable GHRPs, it can be taken once daily as a capsule or liquid, making it the most convenient GH secretagogue.
No - MK-677 works by stimulating GH release from the pituitary (secretagogue mechanism), not by replacing GH. Long-term studies (up to 2 years) show no suppression of the natural GH axis.
Taking MK-677 before bed coincides with the natural nocturnal GH pulse, amplifying it. This also means the significant hunger effect occurs during sleep, reducing daytime appetite disruption.
Legal Status by Region
This information is provided for educational and research purposes only. Not approved for human consumption by the FDA or any regulatory body. Always consult a qualified medical professional.