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Growth Factors & IGF

MGF (Mechano Growth Factor)

Also known as Mechano Growth Factor · IGF-1Ec · IGF-1Ec splice variant · MGF E-peptide

PreliminarySubcutaneous injectionIntramuscular injectionNot approved by the FDA for any indication; characterized as a research compound with no approved therapeutic use in any jurisdiction, and not an established 503A/503B compounded preparation (it was not on the FDA interim 503A Category 2 bulks list). Prohibited at all times for athletes under the WADA Prohibited List, category S2 (peptide hormones, growth factors, and related substances).

MGF (Mechano Growth Factor) refers to a splice variant of the insulin-like growth factor 1 (IGF-1) gene that is expressed locally in tissues such as skeletal muscle in response to mechanical loading and damage. In humans it corresponds to the IGF-1Ec isoform, while the rodent ortholog used in much preclinical work is IGF-1Eb; the two share only part of their E-domain sequence. The compound usually studied or sold as 'MGF' is the synthetic 24-amino-acid C-terminal E-peptide of this variant, which research describes as acting at least partly independently of mature IGF-1, with proposed effects on activating quiescent satellite (muscle stem) cells and promoting myoblast proliferation. It has been examined in preclinical work for roles in muscle, cardiac, neural, and bone tissue. The current evidence base is almost entirely preclinical, consisting of animal models and in-vitro cell studies, with no completed human clinical efficacy or safety trials reported as of 2026. Some literature has also raised theoretical concerns about oncogenic potential given its growth-factor activity.

Studied / used for

  • Investigated for skeletal muscle repair and hypertrophy via satellite cell activation (preclinical)
  • Studied for age-related muscle loss (sarcopenia) in animal models
  • Investigated for cardiac tissue preservation following myocardial injury (preclinical)
  • Studied for neuroprotection and neurogenesis in brain injury and aging models
  • Investigated for bone repair and mechanotransduction (preclinical)

Commonly reported side effects

  • Injection-site reactions such as redness, swelling, or discomfort (commonly reported anecdotally)
  • Localized soreness near the injection area (commonly reported anecdotally)
  • Concern about oncogenic/carcinogenic potential raised in the research literature given its growth-factor activity
  • Theoretical satellite cell depletion with chronic activation (noted in research, not from human trials)
Preliminary. Mostly early or animal studies. This reflects the strength of the research base, not effectiveness or a recommendation.

Not medical advice.

This is an educational reference. Peptalk does not recommend, prescribe, endorse, or rate any compound, and provides no dosing information. Do not start, stop, or change any peptide, hormone, supplement, or therapy based on this page. All clinical decisions must be made with your licensed healthcare provider.

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