MK-677 (Ibutamoren) vs Mod GRF 1-29 vs PEG-MGF
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 →Mod GRF 1-29
Mod GRF 1-29 (Modified GRF 1-29, also called CJC-1295 without DAC or Tetrasubstituted GRF 1-29) is a modified growth hormone-releasing hormone analog with improved stability over natural GHRH.
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 →Side-by-Side Comparison
| Aspect | MK-677 (Ibutamoren) | Mod GRF 1-29 | PEG-MGF |
|---|---|---|---|
| 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. | Binds to GHRH receptors in the pituitary gland to stimulate growth hormone release. Four amino acid substitutions improve resistance to enzymatic degradation while maintaining biological activity. | 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. |
| Typical Dosage | Typical dosing: 10-25mg taken orally once daily. Often taken at night due to sleep benefits and appetite increase. | Typical dosing: 100-300mcg administered 2-3 times daily, usually combined with a GHRP like Ipamorelin for synergistic effects. | Research protocols typically use 200-400mcg injected into targeted muscle groups 2-3 times weekly, usually post-workout. |
| Administration | Oral administration (capsule or liquid). Can be taken with or without food. Long half-life allows once-daily dosing. | Subcutaneous injection. Best administered on empty stomach. Short half-life (~30 minutes) necessitates multiple daily doses, unlike DAC version. | Intramuscular injection, ideally into muscles trained that day. Best administered post-workout when satellite cell activation is relevant. |
| 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. | Flushing, headache, dizziness, and injection site reactions. Generally well-tolerated. May cause water retention. | Injection site soreness, potential hypoglycemia, and localized swelling. Generally well-tolerated. |
| Best For |
What They Have in Common
MK-677 (Ibutamoren), Mod GRF 1-29, PEG-MGF are all commonly used for:
Key Differences
Unique to MK-677 (Ibutamoren):
Unique to Mod GRF 1-29:
Detailed Analysis
Commonalities
Both MK-677 (Ibutamoren) and Mod GRF 1-29 are commonly used for Muscle Growth, Fat Loss, Recovery & Healing, Sleep Quality.
Which Should You Choose?
MK-677 (Ibutamoren) has stronger evidence for Sleep Quality.
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 Mod GRF 1-29 and PEG-MGF are commonly used for Muscle Growth, Recovery & Healing.
Which Should You Choose?
Mod GRF 1-29 has stronger evidence for Muscle Growth.