The Dietary Supplement Innovation Act clarifies and expands the rules governing when drugs and biological products can be added to foods and dietary supplements. Currently, the law generally prohibits adding FDA-approved drugs to dietary supplements, but this bill creates several exceptions that would allow ingredients to remain in supplements even if they undergo drug development, as long as they were marketed as food or supplements before drug testing began or if clinical trials have been inactive for at least seven years. The bill also establishes new standards for how the FDA must evaluate whether a substance in a supplement is actually a drug, requiring the agency to consider differences in how the substance is used, its dosage, concentration, and safety profile when added to supplements rather than treating it identically to its pharmaceutical form. Additionally, the legislation allows people to immediately challenge FDA warning letters about drug preclusion in court, and it shifts the burden of proof to the federal government to prove a supplement violates the law rather than requiring companies to prove compliance. The bill does not specify any new funding or implementation timelines beyond immediate applicability of its provisions.