VITAMINS & SUPPLEMENTS · GUIDE
Proprietary Blends in Brain Supplements: Hidden Amounts and Hidden Ingredients
What a proprietary blend on a brain supplement label does and does not tell you, how it differs from undeclared ingredients, and what to check with a pharmacist or clinician.
Content last updated . This page has not been medically reviewed.
Back to NootropicsWhat a proprietary blend is
The FDA's Dietary Supplement Labeling Guide (April 2005, nonbinding recommendations) says a proprietary blend must be identified by the term "Proprietary Blend" or a descriptive or fanciful name. On the same line, the total weight of the blend's "other dietary ingredients" is listed, and the ingredients are listed underneath in descending order of predominance by weight. [1] The guide also says that dietary ingredients with established reference values must be listed separately with their individual weights. [1] We read the 2005 guide as posted by the FDA and did not separately read the current regulation text, so check current rules before relying on the details.A 2023 article in the Journal of Nutrition explains the consequence: the weight of the blend and the ingredient names must be declared, but not the amounts of individual ingredients, so the amount of an ingredient in a blend is not available for calculating intake or for determining doses in clinical trials. [2]
Why it matters for brain supplements
- You cannot compare with research. Studies attribute outcomes to a stated form and amount of one ingredient. A blend's label cannot be matched to those studies. See the ingredient-by-ingredient evidence table.
- Stimulant totals can be unclear. The FDA says many packaged foods, beverages and dietary supplements containing caffeine voluntarily state how much they contain, and advises care the first time you use a product with added caffeine when the amount is not declared. [3] A US label analysis of 75 top-selling energy drinks and shots found 15 products containing proprietary blends with undisclosed ingredient amounts. [4]
- Evidence labels apply per ingredient. Some ingredients in a typical formula have mixed or no compelling evidence for memory. [5] A blend can list them together under one weight.
Hidden amounts versus hidden ingredients
| Hidden amounts (proprietary blend) | Hidden ingredients (undeclared) | |
|---|---|---|
| What it is | Ingredient names and total weight listed; individual amounts not listed | An ingredient is in the product but not on the label |
| Status per sources we read | Described in FDA labeling guidance and a 2023 journal article [1] [2] | The FDA says products must accurately list their ingredients and cannot contain hidden drug ingredients [6] |
| What it prevents | Comparing with trial amounts and totalling intake | Checking interactions and allergies |
| What to do | Ask a pharmacist what the label can and cannot show | Report suspicious products and talk to a health care professional |
The FDA describes hidden ingredients as often prescription drug ingredients, banned substances or harmful chemicals, and says that words such as "herbal" or "all natural" do not mean a product is safe. [6] A 2023 review of 50 "nootropic" supplements discussed unauthorized ingredients in this category. [7] For more, see hidden and undeclared ingredients in focus and brain products.
Frequently asked questions
What does a proprietary blend mean on a label?
The blend is named, its total weight is given, and its ingredients are listed by descending weight, without individual amounts. [1]
Is a proprietary blend illegal?
The sources we read describe it as allowed under US labeling guidance. Undeclared ingredients are a separate matter and are illegal per the FDA. [1] [6]
Can I tell how much caffeine is in a blend?
Not always. Caffeine amounts on supplements are often voluntary, and the FDA suggests caution when the amount is not declared. [3]
Does "natural" or "herbal" on the label mean the product is safe?
No. The FDA says such words do not mean a product is safe. [6]
Can a pharmacist check a blend against my medicines?
A pharmacist can review the listed ingredients, but a blend's missing amounts limit what can be checked. Bring the full label. [2]
More details: evidence, limits and cautions
The details behind this page: cautions, limits of the evidence and where sources disagree. Open any note to read it.
Limits and uncertainty
Safety and who should ask a clinician
References
- US Food and Drug Administration, Dietary Supplement Labeling Guide: Chapter IV. Nutrition Labeling (April 2005, nonbinding recommendations). Read 2026-10-23.
- Saldanha LG et al. Perspectives on the Use of Proprietary Blends in Dietary Supplements. J Nutr 2023. PMID 37004873. Abstract read 2026-10-23.
- US Food and Drug Administration, Spilling the Beans: How Much Caffeine is Too Much?. Content current as of 08/28/2024. Read 2026-10-23.
- Jagim AR et al. Prevalence and Amounts of Common Ingredients Found in Energy Drinks and Shots. Nutrients 2022. PMID 35057494. Abstract read 2026-10-23.
- Hersant H et al. Over the Counter Supplements for Memory: A Review of Available Evidence. CNS Drugs 2023. PMID 37603263. Abstract read 2026-10-23.
- US Food and Drug Administration, Avoiding Products Contaminated with Hidden Ingredients. Content current as of 06/10/2025. Read 2026-10-23.
- Jedrejko K et al. Unauthorized ingredients in nootropic dietary supplements: A review of the history, pharmacology, prevalence, international regulations, and potential as doping agents. Drug Test Anal 2023. PMID 37357012. Abstract read 2026-10-23.