Proprietary blends: how they can hide the dose

A proprietary blend is a group of ingredients listed together under one name, such as "Metabolic Complex," with a single total weight instead of an amount for each ingredient. It can hide the dose of each ingredient because the rules ask only for the total and for the order of the ingredients by weight. You can tell how much the blend weighs, but not how much of each ingredient is in it.

Below is what the FDA rule says, what it leaves out, how to judge a blend on a label, and what to ask a seller.

What is a proprietary blend on a supplement label?

The FDA's labeling guide explains that a blend must be identified with the term "Proprietary Blend" or an "appropriately descriptive term or fanciful name." That is why blends come with names like "Fat-Burning Complex" or "Liver Purification Complex." The name is chosen by the seller, and it can sound impressive without telling you anything about the contents.

Blends are a legal labeling format, not a scam by definition. Sellers use them to keep a formula private, and some have a fair reason to. The problem for the reader is what the format removes: the one number you need to compare a product with the research.

What do the FDA rules say about blends?

The rule is 21 CFR 101.36, and the FDA's labeling guide summarizes it in plain terms. For a blend, the label must show:

• the name of the blend, with the total weight of all the "other dietary ingredients" in it on the same line;
• the ingredients inside the blend listed under that name in descending order of predominance by weight, so the heaviest comes first;
• a symbol pointing to the footnote "Daily Value Not Established" next to those ingredients.

The guide adds one more point that is easy to miss: dietary ingredients that have a Daily Value, such as vitamin C, vitamin D or calcium, must be listed separately with their own individual weights. They cannot be tucked inside a blend to hide the amount. So a blend can only hold ingredients that have no Daily Value, which is most herbs, plant extracts, amino acids and similar substances.

How can a blend hide the dose of each ingredient?

The total weight tells you the size of the pile, not how it is divided. Take a blend of seven ingredients that weighs 525 mg per serving. The rule says the heaviest ingredient comes first. That means the first ingredient weighs at least 75 mg (525 divided by 7) and the last weighs at most 75 mg. Beyond that, the split could be 400 mg of the first ingredient and a few milligrams each of the other six. The label would look the same.

This is the core of the problem. Most claims for an ingredient rest on studies that used a specific amount. If the blend does not say how much of that ingredient is in the capsule, you cannot check it against the study. And the ingredient that a sales page talks about the most is not necessarily the one that weighs the most.

The order helps a little. Since the list runs from heaviest to lightest, an ingredient near the bottom is a small share of the blend's total. It is not a full answer, but it is more than a bare list.

Which DoseAudit reviews show this in practice?

Three of our reviews illustrate three different degrees of disclosure. We are repeating what each review found, using the sales page and checkout as they were on the date of the check.

One blend, seven ingredients. Our Gluco6 review found a label that gives exact amounts for vitamin D3, vitamin B1 and chromium, plus a company name, address and phone number. But seven plant and stimulant ingredients (Sukre, theobromine, green tea, eleuthero, theacrine, cinnamon and Gymnema Sylvestre) share a single 525 mg total. In the words of the review, none of their individual amounts can be checked against the research cited for each one.

Amounts not stated at all. Our Prosta Peak review found that the sales page and checkout page give no milligram amount for any ingredient and no total blend weight either. The review calls this more hidden than a typical proprietary blend, which usually at least states a combined total. Its best-known ingredient, saw palmetto, was tested in a large Cochrane review, and without a stated dose there is nothing to compare it with.

A dose the research used, and a scoop that does not show it. Our Nitric Boost review found eight ingredients and no amount printed for any of them. The page's own centerpiece study used 6 grams a day of a single ingredient, L-arginine, on its own. The review's point is that a scoop shared among eight ingredients, with no split given, offers no way to tell whether the product comes anywhere near that amount.

The lesson is the same in all three: when the amount is missing, the research cited on the page cannot be tied to what you would swallow.

How do you judge a blend?

Use this short list when you see one:

1. Find the total weight. If a blend of eight ingredients weighs 300 mg per serving, the average ingredient is under 40 mg. Compare that with the amounts studied for the ingredients the page brags about.
2. Read the order. The first ingredients weigh the most. Is the one the sales page emphasizes near the top or near the bottom?
3. Look for the studied amount. Search the ingredient name plus "dose" on the NIH Office of Dietary Supplements or PubMed. If the studied amount is larger than the whole blend, the label cannot supply it.
4. Count how many ingredients share the total. More ingredients in the same weight means a smaller share for each.
5. Check that the label is real. A page that names ingredients and shows no Supplement Facts panel is not showing a label at all. Our guide to reading a Supplement Facts label on the DoseAudit blog covers the panel line by line.

What should you ask the seller?

A serious seller can answer these in a few lines. Send them before you buy, and keep the reply.

• What is the amount per serving of each ingredient in the blend?
• Is each herbal ingredient an extract, and at what ratio or standardization?
• Can you send a clear image of the current Supplement Facts panel?
• Who is the manufacturer, and where is it located?
• Is there any third-party testing, and can I see the report?

Refusing to give any amount is an answer too. It does not prove a product is poor, but it means you cannot verify it, and you would be paying for a formula you cannot check. Read the ClickBank refund guide before you order anything you cannot verify, so you know how to get your money back if the label does not match.

If you take prescription medicine, are pregnant or plan surgery, show the label to a doctor or pharmacist first. Hidden amounts make it harder for them to judge interactions. The NIH's NCCIH says to tell your health care providers about all supplements you take.

FAQ

Is a proprietary blend legal?

Yes. The FDA's rule allows blends, as long as the label shows the blend name, the total weight, and the ingredients in descending order by weight. It also means that a blend is not evidence of a problem by itself.

Does the FDA check that a blend is accurate?

The FDA says it does not approve dietary supplements before they are marketed and that firms are responsible for making sure their products are not misbranded. That means the label is the seller's own statement.

Is a blend with a long ingredient list a good sign?

Not by itself. A long list can look thorough, but the total weight is shared among all the ingredients. Divide the total by the number of ingredients to see the average share.

Can I find the hidden amounts myself?

Not from the label. The order gives a rough ranking, and the total gives an upper limit for any one ingredient. Anything more needs the seller or a lab, and NCCIH notes that what is on a label may not always match what is in the product.