MGF (Mechano Growth Factor) vs MK-677 (Ibutamoren)
A detailed comparison to help you understand the differences and choose the right peptide for your research goals.
MGF (Mechano Growth Factor)
MGF (Mechano Growth Factor) is a splice variant of IGF-1 that is produced locally in muscle tissue in response to mechanical stress. The non-PEGylated form has a very short half-life.
Full details →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 →Side-by-Side Comparison
| Aspect | MGF (Mechano Growth Factor) | MK-677 (Ibutamoren) |
|---|---|---|
| Dose Range | 400 mcg–1.2 mg | 10 mg–25 mg |
| Frequency | Less than daily | 1x daily |
| Cycle Length | 4–6 weeks | 8–24 weeks |
| Route | intramuscular | oral |
| Mechanism | Activates muscle satellite cells (stem cells) and promotes their proliferation without differentiation, priming them for fusion with existing muscle fibers during repair and growth. | 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. |
| Typical Dosage | Due to extremely short half-life (minutes), typical protocols use 100-200mcg injected directly into target muscles immediately post-workout. | Typical dosing: 10-25mg taken orally once daily. Often taken at night due to sleep benefits and appetite increase. |
| Administration | Intramuscular injection into trained muscles within minutes of workout completion. Must be used immediately after reconstitution due to instability. | Oral administration (capsule or liquid). Can be taken with or without food. Long half-life allows once-daily dosing. |
| Side Effects | Injection site soreness, potential hypoglycemia, localized swelling. Short half-life limits systemic effects. | Increased appetite and water retention are most common. May cause lethargy, vivid dreams, and mild numbness. Can affect blood glucose and insulin sensitivity. |
| Best For |
What They Have in Common
MGF (Mechano Growth Factor), MK-677 (Ibutamoren) are both commonly used for:
Key Differences
Unique to MK-677 (Ibutamoren):
Which Has Stronger Evidence?
- Muscle Growth: MK-677 (Ibutamoren) has stronger research support.
| Goal | MGF (Mechano Growth Factor) | MK-677 (Ibutamoren) |
|---|---|---|
| Muscle Growth | medium | high |
| Recovery & Healing | medium | medium |
Key Studies
MGF (Mechano Growth Factor)
- The role of mechano growth factor in chondrocytes and cartilage defects: a concise review.
Acta biochimica et biophysica Sinica, 2023
- Pretreatment with mechano growth factor E peptide attenuates osteoarthritis through improving cell proliferation and extracellular matrix synthesis in chondrocytes under severe hypoxia.
International immunopharmacology, 2021
- Mechano growth factor interacts with nucleolin to protect against cisplatin-induced neurotoxicity.
Experimental neurology, 2020
MK-677 (Ibutamoren)
- Knowing the minimal detectable dose can facilitate the interpretation of a hair test result: II. Case example with ibutamoren (MK-677), a growth hormone secretagogue.
Clinica chimica acta; international journal of clinical chemistry, 2026
- Hepatotoxicity induced by MK-677.
BMJ case reports, 2025
- Investigating the P53-dependent anti-cancer effect of ibutamoren in human cancer cell lines.
Basic & clinical pharmacology & toxicology, 2025
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