A supplement label can read like a clean bill of health: “supports immunity”, “boosts energy”, “helps your body fight back”. But in the UK these words are governed by rules, and some of the most reassuring-sounding phrases are exactly the ones that aren’t allowed. The line between what a label may legally say and what it implies is narrow, and it’s where consumers most often get misled. Here’s how to read past the marketing.
Supplements are food, not medicine
In Great Britain, vitamin and mineral supplements are regulated as food, under the Food Safety Act 1990 and the Food Supplements (England) Regulations 2003, with the Food Standards Agency overseeing safety and honest labelling. That matters because food cannot legally claim to treat, prevent or cure illness. Only a licensed medicine can do that, and licences are granted by the Medicines and Healthcare products Regulatory Agency (MHRA).
So a phrase like “helps prevent colds” is a medicinal claim and is not permitted on a supplement. “Vitamin C contributes to the normal function of the immune system” is allowed, because it is an authorised health claim about maintaining normal function, not curing anything.
The two kinds of claim that are allowed
Since 1 January 2021, a claim is only permitted if it appears on the Great Britain Nutrition and Health Claims (NHC) Register. There are two types:
- Nutrition claims — describing what’s in the product, e.g. “high in fibre” or “source of vitamin D”. These are tied to set threshold amounts; a product can only say “high in” if it genuinely meets the figure.
- Health claims — describing what an authorised nutrient does, always in the language of supporting or maintaining normal function, e.g. “calcium is needed for the maintenance of normal bones”.
If wording strays from the approved phrasing, or implies more than “normal function”, it has quietly crossed the line.
The phrases that should make you pause
| What the label says | What it usually signals |
|---|---|
| “Supports normal immune function” | Likely an authorised health claim — check the nutrient is actually present in a meaningful amount. |
| “Fights / prevents / treats [condition]” | A medicinal claim not permitted on food. A red flag. |
| “Detox”, “boost”, “cleanse”, “miracle” | Marketing language with no agreed scientific meaning; not authorised claims. |
| “Clinically proven” with no reference | Vague substantiation. The Advertising Standards Authority requires robust evidence. |
| Claims about a herb or plant extract | Most botanical claims are “on hold” — neither fully authorised nor settled — so confident wording here is doing more than the rules support. |
What the label must tell you
A compliant UK supplement label is legally required to carry certain information. Use it as your checklist:
- The recommended daily dose, and a warning not to exceed it.
- The amount of each nutrient, plus the % Nutrient Reference Value (NRV) where one exists, so you can judge the dose against need.
- A statement that supplements are not a substitute for a varied diet.
- A note to keep out of reach of children.
If a product hides the dose, omits the %NRV, or buries the “do not exceed” warning, that tells you something about how carefully it was made.
Where to check, for free
You don’t have to take the label’s word for it. The GB NHC Register (on GOV.UK) lists every authorised claim and its exact wording. The ASA publishes rulings on misleading supplement adverts. For whether you actually need a supplement, the NHS website sets out the few cases where one is genuinely advised — vitamin D in winter, folic acid in pregnancy, and certain at-risk groups — based on Reference Nutrient Intakes from SACN, the Government’s nutrition advisory committee. A pharmacist can talk you through interactions with any medicines you take.
The bottom line
Honest supplement labels are modest by design: they describe normal function, name real amounts, and warn you not to overdo it. The moment a label promises to fix, prevent or cure something, it has stepped outside the rules — and that’s your cue to put it down and check the official sources. Most people eating a balanced diet need very few, if any, supplements at all.
Health Choice UK gives independent, educational guidance — not medical advice. For anything personal, speak to your GP, pharmacist or the NHS.