Research

Hormonal

Activation of the IGF1-Akt/PKB pathway in skeletal muscle drives hypertrophy by simultaneously stimulating protein synthesis via mTOR and inhibiting protein degradation via FoxO transcription factors.

To build muscle, you must stimulate the IGF1-Akt pathway. This happens naturally through resistance training and adequate nutrition. The paper confirms that activating this pathway increases muscle size by building protein and stopping breakdown. Focus on progressive overload in training and sufficient protein intake to support this biological process.

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A central component in this cascade is the kinase Akt, also called protein kinase B (PKB), which controls both protein synthesis, via the kinases mammalian target of rapamycin (mTOR) and glycogen synthase kinase 3b (GSK3b), and protein degradation, via the transcription factors of the FoxO family.
Stefano Schiaffino et al. · Skeletal Muscle · 2011

Why this rating

Based on extensive in vivo genetic models (transgenic, knockout, and transfection) in mice and rats.

Source

Regulation of skeletal muscle growth by the IGF1-Akt/PKB pathway: insights from genetic models

Stefano Schiaffino et al. · Skeletal Muscle · 2011

DOI 10.1186/2044-5040-1-4

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DOI resolved against Crossref · corpus check 2026-06-10

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