Flip a supplement bottle over and you may see a single line doing the work of five or six ingredients: a named "complex" or "blend" followed by one combined weight in milligrams. It looks like disclosure. It is not. The individual amount of each ingredient inside that blend is legally allowed to stay hidden, and that gap between what a label shows and what it actually tells you is one of the most consumer-unfriendly quirks in supplement labelling — and one every label-literate shopper should know how to spot.
What a Proprietary Blend Actually Discloses
A proprietary blend groups several ingredients under one trademarked or invented name — a "recovery matrix," an "energy complex" — and lists that group as if it were a single ingredient. The rules that apply to ordinary ingredient lists still apply here in one respect: everything inside the blend must be named, and named in descending order by weight, so the first-listed ingredient is present in the largest amount and the last in the smallest. What the label does not have to show is how much of each one there is. You get the total weight of the whole blend, not a breakdown of its parts.
Why This Is Legal, Not a Labelling Error
This isn’t a gap that slipped through unnoticed — it’s a permitted format. The stated justification is protecting a manufacturer’s formulation: a specific ratio of ingredients can represent real product-development investment, and grouping the blend under one figure stops a competitor reading the label and copying the recipe exactly. UK food supplement labelling law, inherited from the same EU-derived framework that still shapes the rules here, requires the amount of any vitamin, mineral or other substance with a nutritional or physiological effect to be declared — but a blend name can satisfy that requirement as a single declared "substance," without breaking out its constituents. Nothing about a proprietary blend is fraudulent on its face. It is a legal format that happens to serve the manufacturer’s interest in secrecy more than the shopper’s interest in comparison.
The practical consequence is what should concern a careful buyer. A blend format makes it just as easy to list one clinically meaningful dose of an active ingredient alongside four cheap filler ingredients in trace amounts, all under one combined weight that sounds generous. Two products can carry an identical "3,000mg proprietary blend" on the front of the label while one delivers a genuinely useful dose of its headline ingredient and the other delivers barely a token amount, diluted by everything listed after it. The total weight tells you almost nothing about the ingredient you actually bought the product for.
Five Ways to Read Around the Blend
You cannot force a brand to publish the individual doses inside a blend, but you can narrow the uncertainty considerably by reading the rest of the label with intent.
- Check the ingredient order. Because the list runs in descending order by weight, an active ingredient named third or fourth out of six is mathematically capped — it cannot be present in more than a small fraction of the blend’s total weight, whatever that total is.
- Compare the total blend weight to the known effective dose. If published research on an ingredient generally uses a dose in the hundreds of milligrams and a product’s entire multi-ingredient blend weighs less than that combined, the headline ingredient cannot possibly be present at a meaningful level once it’s sharing that weight with everything else on the list.
- Look for the ingredients that appear alone, outside the blend. Manufacturers confident in a specific dose usually declare it individually, with its own milligram figure and %NRV where one exists. An ingredient that’s been folded into the blend rather than declared separately is often the one they’d rather you not scrutinise.
- Treat "clinically studied" claims against a blend with particular caution. If the research behind a claim used a specific isolated dose of an ingredient, and the label only shows that ingredient buried inside an undisclosed blend, there’s no way to confirm the product actually matches the dose the claim is borrowing credibility from.
- Favour brands that quote the batch-specific breakdown on request or online. Nothing in the regulations bars a manufacturer from voluntarily publishing individual amounts even while using a blend name on the physical label — some do, most don’t, and the difference is a useful signal about how much scrutiny a brand is comfortable with.
The One Place the Law Does Bite: Health Claims
Proprietary blends have far less room to hide the moment a product carries an authorised nutrition or health claim. Any substance a claim is made about must appear in the product’s nutrition information with its quantity stated, and for vitamins and minerals that quantity must also be expressed as a percentage of the Nutrient Reference Value. The wording of the claim itself has to match the authorised form on the GB Nutrition and Health Claims Register, and the product has to actually contain the substance at the level the claim’s conditions of use require — a brand can’t borrow the credibility of an authorised claim for an ingredient it has buried at a trivial dose inside a blend. In practice this means the ingredient a label makes a specific claim about is one of the few blend components you can usually pin an exact figure to; it’s everything else in the blend, the ingredients riding along without a claim attached, that stays opaque.
Disclosed Label vs. Proprietary Blend Label, Side by Side
| What the label shows | Fully disclosed ingredient list | Proprietary blend label |
|---|---|---|
| Individual ingredient amounts | Stated in mg for each ingredient | Not stated — only the combined total |
| Ingredient order | Confirms and matches the stated amounts | Descending by weight, but amounts unconfirmed |
| %NRV shown | Yes, for any vitamin or mineral | Only for ingredients carrying an authorised claim |
| Comparable across brands | Directly, milligram for milligram | Only by total blend weight, which can mislead |
| Filler dilution visible | Yes — low-dose fillers show their true amount | No — fillers can sit inside the same total as actives |
The Bottom Line
A proprietary blend on a supplement label isn’t automatically a sign of a poor-value product, but it is a sign that the label is doing less work than it looks like it’s doing. The regulations that govern food supplement labelling in the UK require a great deal of honesty on the individual ingredients a brand chooses to declare separately — and almost none on the ones it chooses to fold into a blend. Reading past the blend name, checking the ingredient order, and weighing the total against what a meaningful dose actually looks like is the difference between buying on the strength of a real formulation and buying on the strength of a persuasive-sounding total weight.