Follistatin vs FGL

A detailed comparison to help you understand the differences and choose the right peptide for your research goals.

Follistatin

Follistatin is a glycoprotein that inhibits myostatin, the protein responsible for limiting muscle growth. By blocking myostatin, follistatin can theoretically allow for increased muscle development beyond natural limits.

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FGL

FGL (FG Loop) is a synthetic peptide that mimics the neural cell adhesion molecule (NCAM) FG loop region. It promotes neuroplasticity and has shown cognitive-enhancing effects in research.

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Side-by-Side Comparison

AspectFollistatinFGL
MechanismBinds to and neutralizes myostatin and activin, both of which are negative regulators of muscle mass. This removes the natural brake on muscle growth, allowing for enhanced hypertrophy.Binds to FGFR1 (fibroblast growth factor receptor 1) to activate downstream signaling cascades that promote neurite outgrowth, synaptic plasticity, and neuronal survival.
Typical DosageResearch protocols typically use 100-300mcg daily, though optimal dosing is not well established. Gene therapy approaches have also been studied.Research protocols have used subcutaneous doses ranging from 1-10mg. Intranasal administration also studied. Optimal dosing not established.
AdministrationSubcutaneous injection. Different isoforms exist (FS344, FS315) with varying properties. Requires careful sourcing due to complexity.Subcutaneous injection or intranasal administration. Research compound with limited human dosing data.
Side EffectsLimited human data. Theoretical concerns about effects on other organs where activin signaling is important.Limited human data available. Animal studies show good tolerability.
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Key Differences

Unique to Follistatin:

Unique to FGL:

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