MGF (Mechano Growth Factor) vs Retatrutide
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 →Retatrutide
Retatrutide (LY3437943) is a first-in-class triple agonist peptide targeting GIP, GLP-1, and glucagon receptors simultaneously. Developed by Eli Lilly, it is currently in Phase 3 clinical trials and has demonstrated the highest weight loss of any obesity medication to date — up to 28.7% body weight reduction at 48 weeks. The triple-receptor mechanism represents the next evolution beyond dual agonists like tirzepatide.
Full details →Side-by-Side Comparison
| Aspect | MGF (Mechano Growth Factor) | Retatrutide |
|---|---|---|
| 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. | Retatrutide is a synthetic peptide that activates three incretin/metabolic hormone receptors: (1) GLP-1 receptor — appetite suppression, insulin secretion, delayed gastric emptying, (2) GIP receptor — enhanced insulin sensitivity, improved fat metabolism, (3) Glucagon receptor — increased energy expenditure, hepatic fat mobilization, thermogenesis. The glucagon receptor component is the key differentiator, adding an energy-expenditure mechanism absent from GLP-1 and dual GIP/GLP-1 agonists. The molecule uses a C20 fatty diacid for albumin binding, enabling once-weekly dosing. |
| Typical Dosage | Due to extremely short half-life (minutes), typical protocols use 100-200mcg injected directly into target muscles immediately post-workout. | Phase 2 trial doses: 0.5 mg, 4 mg, 8 mg, and 12 mg weekly. The 12 mg dose produced maximum weight loss (28.7%). Phase 3 trials are evaluating doses up to 12 mg. Dose escalation schedule similar to other GLP-1s (start low, increase every 4 weeks). Final approved dosing not yet established — Phase 3 trials ongoing. |
| Administration | Intramuscular injection into trained muscles within minutes of workout completion. Must be used immediately after reconstitution due to instability. | Subcutaneous injection, once weekly. Phase 3 trials use pre-filled single-dose pens. Not yet commercially available — estimated FDA approval ~2027-2028. |
| Side Effects | Injection site soreness, potential hypoglycemia, localized swelling. Short half-life limits systemic effects. | Phase 2 data: nausea (up to 25%), diarrhea (up to 22%), vomiting (up to 15%), constipation, decreased appetite. GI side effects were dose-dependent and generally mild-to-moderate. Lower rates of nausea compared to semaglutide, potentially due to GIP component. Increased heart rate observed at higher doses. |
| Best For |
Key Differences
Unique to MGF (Mechano Growth Factor):
Unique to Retatrutide:
Detailed Analysis
Commonalities
MGF (Mechano Growth Factor) and Retatrutide are used for different purposes and have limited overlap in their applications.
Which Should You Choose?
Choose MGF (Mechano Growth Factor) for Muscle Growth, Recovery & Healing. Choose Retatrutide for Fat Loss.
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