MK-677 (Ibutamoren)
MK-677 (Ibutamoren)
Also known as: MK-677, Ibutamoren, MK-0677, L-163, 191, Nutrobal
Overview
Key Facts
Primary Goal: Research and therapeutic applications of MK-677 (Ibutamoren)
Mimics ghrelin by agonizing the GHS-R1a receptor to stimulate pituitary GH release. Produces sustained GH elevation by activating both hypothalamic and pituitary ghrelin receptors.
Dosing Information
24 hours
10–25 mg
once daily
8-16 weeks (some research protocols extend longer)
Benefits
- Oral administration — no injections required
- Sustained 24-hour GH and IGF-1 elevation
- Significant improvement in sleep quality
- Increased lean body mass in clinical studies
- Improved bone mineral density with long-term use
- Convenient once-daily dosing
Side Effects
Mechanism of Action
Mimics ghrelin by agonizing the GHS-R1a receptor to stimulate pituitary GH release
Produces sustained GH elevation by activating both hypothalamic and pituitary ghrelin receptors
Increases appetite through hypothalamic NPY/AgRP signaling pathway
Does not suppress natural GH pulsatility or HPTA function
Contraindications
Do not use this peptide if any of the following apply:
- Insulin resistance or type 2 diabetes
- Active malignancy
- Congestive heart failure (fluid retention risk)
- Pregnancy or breastfeeding
Storage & Reconstitution
Unreconstituted (Powder)
Reconstituted (Mixed)
Research Summary
MK-677 has been studied in multiple Phase II trials for muscle wasting, osteoporosis, and GH deficiency. A landmark 2-year study in elderly adults demonstrated sustained increases in GH and IGF-1 without tachyphylaxis, along with improved lean mass. However, concerns about insulin resistance and glucose metabolism have prevented FDA approval to date.
Frequently Asked Questions
Common questions about MK-677 (Ibutamoren)
UK-Specific Information
Exclusive data points and guidance for UK residents using MK-677 (Ibutamoren)
UK Lab Testing
UK Lab Testing
Recommended labs: Medichecks, Thriva (£89-£149 for peptide safety panel)
Why this matters: UK-specific lab testing guidance not available on US competitor sites
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Note: Peptide stacking should only be done under the guidance of a qualified healthcare professional. Individual responses may vary.
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