A vitamin precursor that the body converts to its active form through normal metabolic processes. Carotene for example is a provitamin of vitamin a.

Folic acid is a precursor of folate, a vitamin found in foods such as spinach and oranges.

Coffee is a major source of the phenolic compound chlorogenic acid and the vitamin B3 precursor trigonelline that have been shown to reduce blood glucose concentrations in animal studies.