The Short Version
DSHEA does not require FDA premarket approval for most dietary supplements, and products need not be proven safe or effective before sale. However, the claim that FDA is "prohibited from reviewing" supplements before marketing overstates the law. DSHEA requires a 75-day premarket notification for New Dietary Ingredients, during which FDA receives and may review safety information. The accurate framing is that FDA lacks mandatory premarket approval authority — not that it is categorically barred from any premarket review.