MK-677 (Ibutamoren)
Also known as: Ibutamoren, Ibutamoren Mesylate, Nutrobal, MK-0677
Overview
MK-677 (ibutamoren) is a potent, orally active, non-peptide GHS-R1a (ghrelin receptor) agonist that mimics ghrelin to stimulate pulsatile growth hormone secretion and sustained IGF-1 elevation. Unlike injectable GH secretagogue peptides, MK-677 is orally bioavailable with a half-life of approximately 24 hours, enabling once-daily dosing. It has been investigated in clinical trials for GH deficiency, muscle wasting (HIV/AIDS, surgery recovery), osteoporosis, and as a potential anti-aging agent. It increases GH pulse amplitude without significantly altering pulse frequency.
Mechanism of Action
MK-677 binds and activates GHS-R1a (the ghrelin receptor) on somatotroph cells of the anterior pituitary and hypothalamic neurons expressing ghrelin receptors. This activates Gq/11-coupled phospholipase C, producing IP3 and DAG, raising intracellular calcium and stimulating GH secretion. Additionally, GHS-R1a activation in the hypothalamus increases GHRH release and reduces somatostatin tone, creating a dual mechanism that amplifies both the frequency and amplitude of GH pulses. Sustained GH elevation drives hepatic IGF-1 synthesis via JAK2/STAT5 signaling.
Potential Benefits
- 24-hour oral dosing convenience vs. injectable GH secretagogues
- Increased GH pulse amplitude and sustained IGF-1 elevation
- Lean mass preservation in catabolic states (surgery, HIV wasting)
- Bone density improvement via IGF-1 signaling
- Improved sleep quality (specifically slow-wave sleep increase)
- Potential anti-aging effects via GH/IGF-1 axis restoration
Dosage Protocols
The following reflects doses used in published research studies. This is not medical advice. Consult a qualified healthcare professional.
| Typical Range | 10-25 mg/day orally |
| Beginner | 10 mg/day at bedtime |
| Intermediate | 15-20 mg/day at bedtime |
| Advanced | 25 mg/day |
| Cycle Duration | 3-6 months; some use year-round at lower doses |
| Cycle Off | 1-2 months; 10 mg/day maintenance sometimes used continuously |
MK-677 is a non-peptide GH secretagogue taken orally. Half-life ~24 hours allows once-daily dosing. Bedtime dosing aligns GH pulse with natural nocturnal release. Significant appetite stimulation and possible insulin resistance at higher doses.
Use our Reconstitution Calculator to determine exact syringe units for your protocol.
Routes of Administration
Oral (Capsule/Tablet) Varies — typically moderate for oral-stable compounds
Take with or without food as specified. Follow product labeling for timing.
Read our full Routes of Administration Guide for detailed comparison of all delivery methods.
Stacking Protocols
Popular research stacks involving MK-677 (Ibutamoren):
Anabolic Recovery Stack
Combines MK-677 (Ibutamoren) with healing (BPC-157) and GH-axis support (CJC-1295 + Ipamorelin) for comprehensive muscle growth and recovery.
Explore our complete Peptide Stacking Guide for more combinations and safety considerations.
Reconstitution
| Typical Vial Size | N/A — available as oral capsules/tablets (10mg, 25mg) |
|---|---|
| BAC Water | N/A — oral formulation |
| Storage | Store capsules/powder at room temperature 15-25°C; protect from moisture |
| Shelf Life | 24-36 months sealed; 6-12 months after opening |
Need exact syringe measurements?
Amino Acid Sequence
N/A (non-peptide small molecule GHS-R1a agonist)
Side Effects & Safety
- Increased appetite (ghrelin mimetic effect)
- Water retention and edema
- Elevated fasting insulin/glucose (monitor in pre-diabetics)
- Fatigue and lethargy at higher doses
- Potential worsening of insulin resistance with long-term use
Safety & Contraindications
This information is for educational purposes only. Consult a qualified healthcare provider before using any peptide.
Active Malignancy
Uncontrolled Diabetes Mellitus
Severe Cardiac Disease
Pregnancy / Lactation
Bleeding Disorders
Active Skin Infection at Injection Site
Drug Interactions
- Insulin / Oral Hypoglycemics:
Pharmacokinetics
| Half-Life | ~4-6 hours |
|---|---|
| Storage | Store at room temperature (15-25°C) in a dry, dark place. Keep tightly closed. Do not refrigerate capsules. |
Synergistic Compounds
The following compounds have been studied alongside MK-677 (Ibutamoren) for potential complementary or synergistic effects:
Learn More
References & Further Reading
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