MK-677 (Ibutamoren) vs PEG-MGF vs Sermorelin
A three-way comparison to help you find the right peptide for your research goals.
MK-677 (Ibutamoren)
MK-677, also known as Ibutamoren, is an orally active growth hormone secretagogue. Unlike peptides, it can be taken orally and has a long half-life, providing 24-hour GH elevation.
Full details →PEG-MGF
PEG-MGF (PEGylated Mechano Growth Factor) is a variant of IGF-1 that is produced in response to muscle damage. PEGylation extends its half-life from minutes to several hours, making it practical for use.
Full details →Sermorelin
Sermorelin is a synthetic analog of GHRH consisting of the first 29 amino acids of the natural hormone. It was previously FDA-approved for GH deficiency diagnosis and treatment in children.
Full details →Side-by-Side Comparison
| Aspect | MK-677 (Ibutamoren) | PEG-MGF | Sermorelin |
|---|---|---|---|
| Mechanism | Acts as a potent, selective agonist of the ghrelin receptor (GHS-R1a). Increases GH and IGF-1 levels without affecting cortisol. Mimics ghrelin's GH-releasing effects. | Activates muscle satellite cells (stem cells) and promotes their fusion to existing muscle fibers for repair and growth. MGF is produced naturally in response to mechanical stress on muscles. | Binds to GHRH receptors in the pituitary gland to stimulate natural GH production and release. Maintains the body's natural feedback mechanisms for GH regulation. |
| Typical Dosage | Typical dosing: 10-25mg taken orally once daily. Often taken at night due to sleep benefits and appetite increase. | Research protocols typically use 200-400mcg injected into targeted muscle groups 2-3 times weekly, usually post-workout. | Typical dosing: 200-500mcg administered once daily, usually before bed. Some protocols use twice daily dosing. |
| Administration | Oral administration (capsule or liquid). Can be taken with or without food. Long half-life allows once-daily dosing. | Intramuscular injection, ideally into muscles trained that day. Best administered post-workout when satellite cell activation is relevant. | Subcutaneous injection, preferably at bedtime to work with natural GH release patterns. Can be combined with GHRPs for synergistic effects. |
| Side Effects | Increased appetite and water retention are most common. May cause lethargy, vivid dreams, and mild numbness. Can affect blood glucose and insulin sensitivity. | Injection site soreness, potential hypoglycemia, and localized swelling. Generally well-tolerated. | Generally well-tolerated. May cause injection site reactions, headache, flushing, or dizziness. Less side effects than direct GH administration. |
| Best For |
What They Have in Common
MK-677 (Ibutamoren), PEG-MGF, Sermorelin are all commonly used for:
Key Differences
Unique to MK-677 (Ibutamoren):
Unique to Sermorelin:
Detailed Analysis
Commonalities
Both MK-677 (Ibutamoren) and PEG-MGF are commonly used for Muscle Growth, Recovery & Healing.
Which Should You Choose?
MK-677 (Ibutamoren) has stronger evidence for Muscle Growth.
Commonalities
Both MK-677 (Ibutamoren) and Sermorelin are commonly used for Muscle Growth, Fat Loss, Recovery & Healing, Sleep Quality.
Which Should You Choose?
MK-677 (Ibutamoren) has stronger evidence for Muscle Growth, Sleep Quality.
Commonalities
Both PEG-MGF and Sermorelin are commonly used for Muscle Growth, Recovery & Healing.
Which Should You Choose?
Both peptides have similar evidence levels for their shared goals. Your choice may depend on specific use case, availability, or personal response.