What does 'FDA-approved' actually mean?

FDA approval is a formal regulatory decision that a drug is safe and effective for its stated use when produced to defined quality standards. Approval requires four things: (1) evidence from adequate and well-controlled clinical trials — usually pivotal phase-3 studies — that the compound produces the claimed clinical effect; (2) evidence that the safety profile is acceptable in the context of the benefit; (3) manufacturing that meets current Good Manufacturing Practices (cGMP) with documented identity, purity, potency, and sterility; (4) labelling that accurately describes the product, the indication, and the safety information.

Approval is always indication-specific. Semaglutide is FDA-approved for type 2 diabetes at doses up to 2 mg weekly under the Ozempic label, and separately for weight management at 2.4 mg weekly under the Wegovy label. These are two different approvals of the same molecule for two different indications. Off-label use (using an approved drug outside its approved indication) is legal for physicians but is not itself covered by the approval.

Approval is not perpetual. Post-market surveillance (phase 4) continues after approval and can lead to labelling changes or withdrawal. Approval is also not evidence that the drug is the best available option for its indication — it means the drug meets the approval threshold, not that it is optimal for every patient. Comparative-effectiveness questions (whether drug A is better than drug B for a specific patient population) often require head-to-head trials that individual approvals do not address.