Peptides Muscle BuildingRecovery & Healing Preclinical (animal) data

MGF (Mechano Growth Factor)

MGF · IGF-1Ec

29 min

Half-life

200–800 mcg

Typical dose

4–6 weeks (reported)

Cycle length

IGF-1 splice variant produced in response to mechanical load; involved in muscle repair signaling.

Key takeaways

IGF-1Ec splice variant made by muscle after mechanical load; acts locally on satellite cells.
Half-life is minutes (~30 min estimated), so protocols dose it right after training.
No human trials exist; every dosing number traces back to rodent and cell studies.
WADA-prohibited as a growth factor under S2.3.

Overview

What it is

MGF (mechano growth factor) is the IGF-1Ec splice variant that skeletal muscle produces locally in response to mechanical load and damage. Its unique C-terminal E-domain activates satellite cells and kicks off repair signaling within hours of injury.

Pharmacokinetics

The peptide clears fast, with an estimated half-life around 30 minutes and roughly 50% subcutaneous bioavailability. That short residence is why research protocols dose it immediately post-training, often injected near the worked muscle.

What the evidence says

Everything rests on animal and in vitro work; no human trials or human PK data exist, and MGF isn't an approved medication. The dose numbers circulating online trace back to rodent studies. PEG-MGF exists specifically to fix the minutes-long half-life. WADA prohibits MGF for tested athletes.

Reported dosing protocols

Protocols reported in research literature and clinic/community use — informational context, not a dosing recommendation.

Use case	Dose	Route	Frequency	Duration
Muscle repair (community)	200–400 mcg	SubQ or IM	Post-training, training days only	4–6 weeks

Pharmacokinetic summary

Model tier: Simple (t½ + F, Tmax estimated)
Half-life: 29 min
Bioavailability: 50%
Typical dose: 0.2–0.8 mg

Frequently asked questions

What does MGF actually do?

In animal models it activates quiescent satellite cells, the stem cells that repair damaged muscle fibers. It's the first local signal in the repair cascade, rising within hours of mechanical overload, before systemic IGF-1Ea takes over.

Why inject MGF right after training?

Native MGF appears within hours of muscle damage and degrades in minutes. Community protocols time the injection post-workout to mimic that pulse and extend the signaling window. Whether exogenous MGF meaningfully adds to the natural pulse is untested in humans.

MGF vs PEG-MGF — what's the difference?

Same active peptide, different half-life. PEGylation shields MGF from breakdown, stretching the half-life from minutes to roughly a day. PEG-MGF allows less frequent dosing, but the longer systemic exposure moves further from the local, pulsatile action seen in animal studies.

References

Estimated — Very short half-life (minutes); splice variant of IGF-1. Yang & Goldspink 2002.
Tang et al., 2017 — mechano growth factor promotes neurogenesis in the aging mouse brain — Characterizes MGF as the IGF-1Ec splice variant with distinct E-domain signaling.
Frontiers in Physiology 2015 — satellite cells in human skeletal muscle plasticity — Reviews IGF-1 splice variants including MGF in muscle regeneration.

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