Follistatin
Follistatin • Also called Follistatin 344, FS-344, FST-344
Follistatin is popular in muscle-growth and physique circles, but FDA has cited it as a compounded substance without a qualifying 503A basis.
Current status
Restricted
Muscle-related interest, with current federal compounding constraints still in play.
FDA category
Not on 503A bulks list
Can pharmacies compound this?
No
Reclassification expected?
Unclear
Current federal sourcing concerns are more basic than a Category 2 dispute: FDA has said compounded follistatin products do not qualify for the usual 503A exemptions.
Primary Use
Muscle-related interest
Also searched as
Follistatin 344, FS-344, FST-344
Regulatory Timeline
Feb 27, 2026
Political pressure and market expectations increased around a future peptide reclassification review.
Mar 15, 2023
FDA peptide compounding scrutiny intensified across 503A and 503B channels.
Apr 1, 2020
Current status signal recorded: FDA warning-letter posture says it is not the subject of an applicable USP or NF monograph, is not a component of an FDA-approved human drug, and does not appear on the 503A bulks list..
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State-specific notes
Texas
Performance-oriented compounds without a 503A basis are difficult for pharmacies to defend.