What UK Supplements Are Actually Allowed to Claim (and What They're Not)

Jul 22, 2026

9 min read

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UK Supplement Basics

A supplement can't say whatever it likes. Here's the line the law draws.

In Great Britain, the words on a supplement label and website are tightly regulated. A product can only make a health claim if that exact claim is authorised — and if the ingredient behind it is present in a meaningful amount. Once you understand the two rules below, you'll be able to read any supplement's marketing and instantly tell the legitimate claims from the hype.

The two rules behind every legitimate claim

Rule 1 — it must be on the authorised list. The Great Britain Nutrition and Health Claims (NHC) Register sets out every wording a supplement is allowed to use, nutrient by nutrient. If a claim isn't on that register, it can't be made — full stop.

Rule 2 — the nutrient must actually be there in a meaningful amount. A nutrient claim is only permitted when a serving provides at least 15% of that nutrient's NRV (Nutrient Reference Value). Below 15%, no claim — even if the ingredient is on the label. And the claim must be pinned to the specific nutrient, not the product as a whole.

Allowed vs not allowed

✓ Allowed

"Vitamin C contributes to the normal function of the immune system"
"Magnesium contributes to a reduction of tiredness and fatigue"
"Zinc contributes to normal cognitive function"
"Vitamin D contributes to the maintenance of normal bones"

— each is on the register, tied to a named nutrient at ≥15% NRV.

✗ Not allowed

"Detoxifies" / "cleanses" / "alkalises"
"Boosts your immune system"
"Treats / prevents / cures [any condition]"
"Lowers cholesterol / blood sugar" (medicinal)
"This form improves memory" (unauthorised form-specific promise)
Any benefit claim for a botanical or novel ingredient with no register entry

The trap most brands fall into. Botanicals (turmeric, ashwagandha, berberine), and popular compounds like butyrate, glutathione, CoQ10 or NAC, have no authorised claims in Great Britain. Legitimate marketing describes what they are; it doesn't promise what they do.

Spot a dodgy claim in 5 checks

1Is it pinned to a named nutrient? Legitimate claims say "vitamin C contributes to…", not "this product supports…".

2Does that nutrient hit 15% NRV per serving? If the label hides the amount or the % NRV, you cannot verify the claim — a red flag.

3Does it mention a disease or body part being "treated"? Disease, diagnosis, cure and prevention language is medicinal — not allowed on a food supplement.

4Are there weasel words? "Detox", "boost", "cleanse", "supercharge", "alkalise" have no regulatory meaning and usually signal an unauthorised claim.

5Is the star ingredient a botanical or exotic compound? If the whole pitch rests on an ingredient with no register entry, the benefit is being implied, not authorised.

Why it matters

These rules exist to protect you from being misled, and they're enforced — by the Advertising Standards Authority (ASA) and Trading Standards. A brand that sticks to authorised wording is one telling you the truth about what its products can and can't do. It's exactly the standard we hold our own product guides to: for a worked example of the 15% line in action, see how to read a magnesium label.

References

Great Britain Nutrition and Health Claims (NHC) Register: gov.uk/…/great-britain-nutrition-and-health-claims-nhc-register
ASA/CAP — Advertising rules for health & food claims: asa.org.uk — food & supplements
Food Standards Agency — Food supplements: food.gov.uk/safety-hygiene/food-supplements

This article is general information about UK labelling rules, not medical or legal advice. Food supplements should not replace a varied, balanced diet or a healthy lifestyle.