Nutrition, Diet & Fasting - Reading the evidence
Proprietary blends and other red flags
Last reviewed 13 August 2026. How we write this.
Why a proprietary blend hides the numbers that matter, plus the other red flags that recur across the aisle.
A proprietary blend is a labelling convention, seen particularly on products made for the US market, that lists several ingredients under one combined weight without saying how much of each is present. UK food-supplement rules require specified compositional and label information, so do not assume that a label permitted in another market meets UK requirements. Wherever individual amounts are hidden, the practical problem is the same: the information needed to judge the formula is missing.
Why the hidden numbers matter
If a blend is 500 mg across six ingredients, the impressive-sounding ones may make up a sliver while a cheap filler dominates. Because the studies behind each ingredient used specific amounts, a blend that hides amounts makes it impossible to know whether any ingredient is present at a level anyone has ever studied. Often the ingredients are listed in descending order, so those near the end may be barely there.
Other recurring red flags
- Miracle language - claims to address many unrelated problems at once.
- Testimonials and before-and-after stories standing in for trials.
- Urgency and scarcity tactics, or a "secret they don't want you to know".
- Proprietary blends that conceal per-ingredient amounts.
- Fear-based marketing that invents a deficiency, then sells the fix.
- No named form, no amounts, or doses far below what studies used.
How to respond
None of these prove a product is useless, but each is a reason to slow down and demand the numbers. Transparent brands tend to disclose amounts and forms because they have nothing to hide. When the information you need is deliberately missing, that absence is itself the finding.
This is educational content about spotting weak marketing, not medical advice, and it endorses no product. Supplements can interact with medicines and health conditions, so always speak to a doctor or pharmacist before deciding to take anything.
Related in this classroom
The studies behind this page
- Food supplement use and labels - UK Department of Health and Social Care
- Food labelling: ingredients list and order by weight - UK Government
Sources for this classroom
Educational content only. Not medical advice, diagnosis or treatment. Always consult a qualified healthcare professional before changing your health regimen.