Follistatin vs Thymalin

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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Thymalin

Thymalin is a polypeptide preparation derived from calf thymus. Developed in Russia, it has been used for decades to support immune function and has shown potential anti-aging effects in long-term studies.

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Side-by-Side Comparison

AspectFollistatinThymalin
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.Regulates the ratio of T-cell subpopulations, stimulates cellular immunity, and enhances phagocytosis. Also affects neuroendocrine regulation and may influence melatonin production.
Typical DosageResearch protocols typically use 100-300mcg daily, though optimal dosing is not well established. Gene therapy approaches have also been studied.Clinical protocols: 5-20mg daily intramuscularly for 3-10 days. Often cycled 1-2 times per year for maintenance.
AdministrationSubcutaneous injection. Different isoforms exist (FS344, FS315) with varying properties. Requires careful sourcing due to complexity.Intramuscular injection. Usually administered in short courses rather than continuously. Often combined with Epithalamin for anti-aging protocols.
Side EffectsLimited human data. Theoretical concerns about effects on other organs where activin signaling is important.Generally well-tolerated. May cause injection site reactions or temporary flu-like symptoms as immune function is modulated.
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Key Differences

Unique to Follistatin:

Unique to Thymalin:

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