MK-677

Quick Facts

• Full Name: Ibutamoren Mesylate
• Aliases: MK-677, L-163,191, Nutrobal
• Category: GH Axis / Muscle / Fat Loss / Sleep
• Type: Non-peptide oral GH secretagogue (ghrelin mimetic small molecule)
• Molecular Weight: 624.8 Da
• Administration: Oral
• Typical Dose: 10–25 mg/day
• Half-Life: ~24 hours (allows once-daily dosing)
• Status: Research Only (not FDA-approved)
• WADA Status: Prohibited (S2)

What It Does

MK-677 (Ibutamoren) is a non-peptide oral ghrelin mimetic that mimics the action of ghrelin to stimulate GH and IGF-1 secretion. Unlike injectable GH secretagogues, it is orally bioavailable and has a 24-hour half-life, enabling once-daily dosing. It significantly elevates GH and IGF-1 levels, improves body composition, enhances slow-wave sleep, and supports bone density — without suppressing endogenous GH production.

Mechanism of Action

1. GHS-R1a agonism (oral): Binds ghrelin receptor in pituitary and hypothalamus → sustained GH pulse amplitude increase throughout the day/night
2. 24-hour half-life: Long half-life produces a more tonic GH elevation vs. pulsatile injection-based protocols
3. IGF-1 elevation: Sustained GH drives robust hepatic IGF-1 production — often 50–100% above baseline
4. Appetite stimulation: Ghrelin pathway activation increases hunger; manage with dietary discipline or GLP-1 support
5. Sleep architecture improvement: Increases slow-wave (delta) sleep duration and quality

Ageless Peps Products

• AP-MK677-Capsules — MK-677 Capsules, $215, retail (draft status)

Dosing Protocols

Standard Protocol

• Dose: 10–25 mg orally
• Timing: Evening / bedtime (amplifies nocturnal GH pulse, manages daytime hunger)
• Frequency: Once daily
• Duration: 3–6 months; can be used continuously long-term at lower doses
• Cycling: Optional 5 days on / 2 days off to manage appetite side effects
• Source: The Peptides Bible, Peptides Made Easy

Conservative (Sleep/Anti-Aging) Protocol

• Dose: 10 mg at bedtime
• Goal: Sleep quality and GH restoration with minimal appetite disruption

Stacks Well With

• PEG-MGF – GH axis + local muscle repair synergy
• IGF-1 LR3 – additive anabolic effect downstream of GH axis
• Ipamorelin – complementary pulsatile GHRP to MK-677's tonic GH elevation
• CJC-1295 NO DAC – GHRH partner for maximal GH axis stimulation
• Semaglutide – manages MK-677-driven appetite increase

Use Cases

• GH Axis Optimization (GH deficiency, age-related GH decline)
• Muscle Growth and lean mass accrual
• Fat Loss via GH-mediated lipolysis
• Sleep Quality and slow-wave sleep enhancement
• Bone Density improvement
• Recovery from training
• Anti-Aging

Contraindications & Safety

• Active malignancy — GH/IGF-1 elevation; avoid
• Insulin resistance / T2DM — elevates blood glucose and fasting insulin; monitor HbA1c
• Fluid retention — edema, carpal tunnel syndrome at higher doses
• Prolactin elevation — mild; monitor
• Long-term IGF-1 elevation — theoretical cancer risk at very high sustained levels
• Common side effects: Hunger (especially first 1–2 weeks), water retention, fatigue (morning), mild insulin resistance

Storage

• Oral capsules/liquid: Room temperature; away from heat, light, moisture
• Stability: Highly stable as a small molecule; 1–2 year shelf life

PubMed Research

Research links will be added after PubMed search

Sources

• The Peptides Bible – GH axis and oral secretagogues
• Peptides Made Easy – Dosing protocols
• Peptide Protocols Master Bible – Evidence-based guide

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