Proprietary Blend

What it is

A proprietary blend is a group of ingredients listed on a Supplement Facts panel under a single combined name and total weight, without disclosing how much of each individual ingredient it contains. US labeling rules allow this: the brand must list the blend's total weight and the ingredients in order of predominance by weight, but not the individual amounts.

What it does

From the manufacturer's perspective, a proprietary blend is often framed as protecting a "secret formula." In practice, its main effect on you as a reader is reduced transparency: you can see what's in the blend and its total size, but not how much of the active ingredients you're actually getting.

What it does NOT do

• It does not tell you the dose of each ingredient. You can't confirm whether an active is present at an effective amount or just a trace.
• It does not guarantee quality or a "premium" formula — despite marketing language, a blend can hide that expensive, headline ingredients are present in tiny amounts ("fairy dusting").
• It is not required for a good product. Transparent brands routinely disclose every dose without any loss of quality.

How to use the concept

• When you see "Proprietary Blend — [X] mg" followed by an undosed ingredient list, treat it as a transparency red flag.
• Compare it against products that print each ingredient's amount — those let you check doses against researched ranges.
• Remember the ingredients are listed by weight order, so anything after the first few is likely present in small amounts.

Sources

1. US Food & Drug Administration. Dietary Supplement Labeling Guide.
2. National Institutes of Health, Office of Dietary Supplements. Dietary supplements: what you need to know.