FDA requires manufacturers to list all of a product’s ingredients on the Supplement Facts panel of a dietary supplement product label, along with the amount of each by weight, except when the ingredients are part of a “proprietary blend.” A proprietary blend is a collection of ingredients often unique to a particular product and sometimes given a special name on a product’s Supplement Facts panel. A proprietary blend might be listed as a “blend,” “complex,” “matrix” or “proprietary formulation.” The specific amount of each individual ingredient in a proprietary blend does not have to be listed; only the total combined amount in the blend must be given. Ingredients in a proprietary blend should, however, be listed in descending order by weight.
The lack of amount for each ingredient is especially important when a proprietary blend contains stimulant (or stimulant-like) ingredients. Stimulants found in supplements can include caffeine, yohimbe, and phenethylamines, as well as illegal ingredients such as DMAA (1,3-dimethylamylamine), DMBA (1,3-dimethylbutylamine), BMPEA (beta-methyl-phenethylamine), and methylsynephrine. (Read the OPSS article about stimulants to learn more.) The only way to know what is in any particular dietary supplement product is through laboratory testing, which is why it’s important to look for third-party certification.
Always read dietary supplement labels carefully. Visit the OPSS article about dietary supplement labeling (including the Supplement Facts panel) to learn more.
Updated 28 March 2018