IGF-1 LR3 vs Mechano Growth Factor (MGF)
Both trade on IGF-1 biology in muscle, but one is a long-acting laboratory reagent and the other is a load-induced splice variant your own muscle already makes.
IGF-1 LR3
An engineered long-acting IGF-1 with zero human muscle-building trials; the risks (hypoglycemia, the growth-factor/cancer concern, a WADA ban) follow straight from the biology.
Full IGF-1 LR3 evidence reviewMechano Growth Factor (MGF)
IGF-1Ec / PEG-MGF
A real load-induced IGF-1 splice variant in muscle biology, but the injected PEG-MGF product has no controlled human outcome trials.
Full Mechano Growth Factor (MGF) evidence reviewSide by side
| IGF-1 LR3 | Mechano Growth Factor (MGF) | |
|---|---|---|
| Marketed for | Muscle growth | Muscle growth, recovery |
| Evidence grade | Preclinical / minimal | Preclinical / minimal |
| Family | GH axis | GH axis |
| Regulatory status | Not FDA-approved | Not FDA-approved |
| How it's obtained | Research-only | Research-only |
| Key human source | Watts, Int J Epidemiol 2023 | Yang & Goldspink, FEBS Lett 2002 |
marks a row where the two differ. Evidence grades come from our evidence matrix, which grades each molecule on the human data for the use it is marketed for.
Our verdict
Neither injectable is supported for muscle building, and the difference is in what kind of evidence each borrows. IGF-1 LR3 is an engineered analog that resists the IGF-binding proteins and stays active far longer than native IGF-1, with no controlled human trials of any kind for muscle growth and predictable mechanistic risks: hypoglycemia, the IGF-axis cancer concern, and a WADA ban. MGF, formally the IGF-1Ec splice variant, does have real human data, but it is about the body's own gene switching on after resistance exercise, not about injecting anything; the pegylated PEG-MGF product sold online has essentially no human outcome trials, no established dose, and no safety profile. They have not been compared directly, and the honest reading of the MGF literature is that training, not a vial, is what raises your MGF.
IGF-1 LR3 fits if
The LR3 page is the better read for understanding why a sustained, systemic growth-factor signal is the specific thing epidemiology and the Laron data counsel against amplifying.
Mechano Growth Factor (MGF) fits if
The MGF page is the better read for seeing how a genuine satellite-cell mechanism and a real human exercise-physiology finding get quietly swapped in for evidence about an injectable.
Where to get it
Where to get peptide therapy
Clinician-led telehealth services that prescribe compounded peptides. The specific peptides offered vary by provider — confirm IGF-1 LR3 availability before ordering.
