Proprietary Blends: Why a Total Weight Hides the Amounts
What a proprietary blend is on a US supplement label, what FDA requires it to show, and why one total weight hides the amount of each ingredient.
Content last updated . This page has not been medically reviewed.
On a US supplement label, a "proprietary blend" lists several ingredients together with one combined weight. The weight of each ingredient inside it is not shown. That means you cannot tell how much of any single ingredient you are getting, and neither can a researcher or a pharmacist from the label alone. [1]
How FDA says a blend must appear
FDA's dietary supplement labeling guide sets the format. The blend is identified by the term "Proprietary Blend" or an appropriately descriptive or fanciful name. [2] On the same line, the total weight of the other dietary ingredients in the blend is listed. [2] Underneath, the ingredients are listed in descending order of predominance by weight. [2] Ingredients that have an official Daily Value, such as vitamins and minerals, must be listed separately with their own weights. [2]
FDA's questions-and-answers page adds that a Supplement Facts panel must give the amount per serving for each dietary ingredient except those that are part of a proprietary blend. [3]
Why makers use them, and what is lost
A 2023 paper by authors from NIH's Office of Dietary Supplements, FDA and an industry trade group says the 1994 law (DSHEA) allows non-nutrient ingredients to be listed as proprietary blends so that companies can protect their unique formulas. [1] The same paper states that, from label information, the amount of a dietary ingredient in a blend is not available for calculating exposures or for determining doses in clinical trials. [1]
| Question | What the sources say | What it means |
|---|---|---|
| Can I see each ingredient's amount? | No; only the blend's total weight is declared. [1] | You cannot compare it with an amount used in a study. |
| Is the order meaningful? | Ingredients are in descending order of predominance by weight. [2] | The first-listed ingredient is present in the largest amount, but by how much is not shown. |
| Can a database fill the gap? | NIH's label database authors name amounts inside proprietary blends as a challenge. [4] | Ask the maker. |
| Do all products hide amounts? | Not described in the sources we read; blends are only one label format. | Check the panel. |
A 2013 pharmacy review of "preworkout" products reported that their labels usually did not disclose all ingredients or their precise amounts. [5] That review covered one product type, so it does not describe all blends.
Why this matters for safety
- Interactions and allergies. Interaction and allergy information depends on what an ingredient is and how much of it there is. With a blend you know the names but not the amounts. Ask a pharmacist; see how interactions work.
- Matching research to the product. A study of one ingredient at one amount tells you little about a blend containing it at an unknown amount. [1]
- Stacking. If two products share an ingredient, a blend makes the total impossible to add up. See amounts and duplicate ingredients.
- Contamination. Blends are not described as more or less likely to be contaminated in the sources we read. For hidden-ingredient warnings see hidden drugs in supplements.
What a reader can safely do
- Read the panel and note the blend's name and total weight.
- If the amount matters for your health or a medicine, ask the maker. FDA suggests contacting the manufacturer, whose name and address are on the label, for more detail than the label provides. [3]
- Bring the label to a pharmacist; see questions to ask your pharmacist.
- Compare products that list each ingredient on its own line; the choice is yours with a clinician's advice. For formula questions see how to evaluate a supplement formula.
Frequently asked questions
Is a proprietary blend illegal?
No. FDA's labeling guide describes how a blend must be shown, and the 2023 paper says the law allows non-nutrient ingredients to be listed this way. [2] [1]
Does a proprietary blend mean the amounts are tiny?
Not stated by the sources we read. The label shows only the total weight. [1]
Can I trust the order of ingredients in a blend?
FDA's guide requires descending order of predominance by weight. [2] It does not say how big the differences are.
Can the maker tell me the amounts?
FDA suggests contacting the manufacturer for more detail than the label provides. [3] Whether they will share it is not described in the sources we read.
Should I avoid blends?
This page does not rank products or give that advice. If amounts matter for a medicine or a condition, ask your pharmacist or clinician.
References
- Saldanha LG et al., Perspectives on the Use of Proprietary Blends in Dietary Supplements, J Nutr 2023. Saldanha LG et al., Perspectives on the Use of Proprietary Blends in Dietary Supplements, J Nutr 2023. Read 2026-10-22.
- FDA, Dietary Supplement Labeling Guide: Chapter IV. Nutrition Labeling (April 2005). FDA, Dietary Supplement Labeling Guide: Chapter IV. Nutrition Labeling (April 2005). Read 2026-10-22.
- FDA, Questions and Answers on Dietary Supplements. FDA, Questions and Answers on Dietary Supplements. Read 2026-10-22.
- Saldanha LG et al., Characteristics and Challenges of Dietary Supplement Databases Derived from Label Information, J Nutr 2018. Saldanha LG et al., Characteristics and Challenges of Dietary Supplement Databases Derived from Label Information, J Nutr 2018. Read 2026-10-22.
- Eudy AE et al., Efficacy and safety of ingredients found in preworkout supplements, Am J Health Syst Pharm 2013. Eudy AE et al., Efficacy and safety of ingredients found in preworkout supplements, Am J Health Syst Pharm 2013. Read 2026-10-22.