Structure/Function Claim
A structure/function claim describes how an ingredient affects normal body structure or function, and is the only benefit claim a dietary supplement may make without drug approval.
Section 403(r)(6) permits a supplement to describe the role of an ingredient in affecting normal structure or function, to characterise the mechanism by which it does so, or to describe general wellbeing. Supports normal joint function is such a claim; relieves arthritis is not. The permission carries conditions: the claim must be truthful and not misleading, the firm must hold substantiation, FDA must be notified within thirty days of first marketing it, and the label must carry the disclaimer that the statement has not been evaluated by FDA.
The boundary is crossed by implication as often as by wording. FDA's labelling criteria treat product names, images, disease-literature citations and testimonials describing recovery from a named condition as capable of establishing a disease claim on their own. The health claim is a separate and often confused category, concerning a diet-disease relationship and requiring significant scientific agreement or authorisation as a qualified health claim.
The value of the distinction is diagnostic. Where a product page discusses a healing rate, a tendon injury or blood glucose control, the claim has left the permitted category whatever the disclaimer says, and the product is being marketed as an unapproved drug. That is a statement about the marketing, not about whether the ingredient does anything.
Two errors recur. The first treats the disclaimer as an authorisation, when it is a required warning that no review occurred and answers nothing to the Federal Trade Commission, which separately requires advertising substantiation. The second treats such a claim as evidence-backed because it sounds cautious; substantiation here is never reviewed before marketing and often rests on in-vitro or rodent work that would not support the human claim implied.