How to read a supplement label.

Quick answer. A UK supplement label must say "food supplement", name the nutrients that characterise it, give the recommended daily dose with a warning not to exceed it, say that supplements are no substitute for a varied diet, and say to keep the product out of reach of young children. Each vitamin and mineral is listed as an amount per daily dose and as a % NRV. Allergens are emphasised in the ingredients list, and the pack carries a best before date. A US "Supplement Facts" panel uses different reference values (% Daily Value), so the same product shows different percentages.

What must a UK supplement label show?

Two sets of rules apply. The Food Supplements (England) Regulations 2003 add supplement-specific wording, and the general food labelling rules in Article 9 of Regulation (EU) No 1169/2011 cover what every packaged food must show. Scotland and Wales have their own matching supplement regulations. Here is the label, part by part, with Immufix as the example.

1. The name: "food supplement".

A supplement cannot be sold "unless the name under which it is sold is 'food supplement'". Brand names and product names sit alongside it. Immufix's label reads "Food supplement", and the product name is Daily Immune Support.

2. What characterises it.

The label must name "the category of any vitamin or mineral or other substance" that characterises the product, so you can see at a glance whether it is, say, vitamin D alone or a mix of vitamins and minerals.

3. The recommended daily dose.

The label has to state "the portion of the product recommended for daily consumption". This is the most important line on the pack, because every amount in the nutrient table is worked out from it. For Immufix it is one 25g scoop, mixed into around 200ml of cold water, once a day.

4. The three compulsory statements.

Every UK supplement must carry a warning not to exceed the recommended daily dose, a statement that supplements should not replace a varied diet, and a statement to keep the product away from young children. Immufix's wording is: "Food supplement. Do not exceed the stated recommended daily dose. Keep out of reach of young children. Food supplements should not be used as a substitute for a varied, balanced diet and a healthy lifestyle."

5. The nutrient table: amount and % NRV.

Each nutrient is listed "in numerical form", as "the amount per portion of the product as recommended for daily consumption", and as "an average amount based on the manufacturer's analysis of the product". Vitamins and minerals that have a nutrient reference value are also shown as a percentage of it. On Immufix, vitamin C reads 100mg, 125% NRV. Our guide to what NRV means shows how the percentage is calculated and why 15% matters.

Ingredients with no NRV, such as Immufix's 6.9g of prebiotic FOS or 1g of L-glutamine, show an amount but no percentage.

6. Ingredients and allergens.

The ingredients are listed in full. GOV.UK's allergen labelling guidance says there are "14 allergens which food businesses must tell you about", and that in prepacked food they "must be clearly labelled within the ingredients list", for example in bold, italics or a different colour. Soya is one of the 14, and Immufix contains soya. A "may contain" line is different: GOV.UK notes that businesses "are not legally required" to use it.

Suitability statements sit nearby. Immufix is vegetarian and gluten free, and the Orange flavour is also vegan.

7. The best before date.

Article 9 requires a date mark: either a best before date or a use-by date. According to GOV.UK, "use-by dates relate to the safety of food, whereas best before dates relate to quality." Article 9 also requires any special storage conditions to be stated.

8. Net quantity and who is responsible.

The pack shows how much is in it and the name and address of the business responsible. A pouch of Immufix holds 750g, which is 30 servings at the recommended dose. Immufix is made in the UK by Be Well Health and Nutrition Limited.

How to read the nutrient table.

Three checks cover most of it.

• Check the dose the figures refer to. All amounts are per recommended daily dose. If a pack's dose is two tablets or two scoops, the figures are for both.
• Check the units. Milligrams (mg) are a thousandth of a gram. Micrograms (µg or mcg) are a millionth. 75µg of selenium is 0.075mg.
• Use the % NRV to compare. It puts every nutrient on the same scale. Below 15%, a nutrient generally cannot carry a claim.

Supplements are exempt from the full nutrition declaration that other foods carry, under Article 29 of Regulation 1169/2011. Some give the main figures anyway. Immufix gives 75 kcal, 13.2g of carbohydrate, 9.9g of sugars and 2.1g of protein per serving.

Why are UK labels different from US Supplement Facts?

A US supplement carries a nutrition panel that, in the words of the US Food and Drug Administration's labeling guide, "is called a 'Supplement Facts' panel". UK packs have no such panel. The main differences:

• Different reference values. The US uses % Daily Value. The UK uses % NRV. The numbers are not the same: the FDA's Daily Values include 90mg for vitamin C and 20mcg for vitamin D, against UK NRVs of 80mg and 5µg.
• The same product reads differently. The 100mg of vitamin C in Immufix is 125% NRV in the UK and would be about 111% Daily Value in the US. Its 1.25µg of vitamin D is 25% NRV here and would be about 6% Daily Value there (both calculated).
• Serving size. The FDA says a serving "equals the maximum amount recommended, as appropriate, on the label". The UK equivalent is the recommended daily dose.
• Blends. US labels may group ingredients that have no Daily Value as a "Proprietary Blend", with one total weight for the blend. UK rules require the amount of each vitamin, mineral or other substance with a nutritional or physiological effect to be stated.

If you buy a supplement made for the US market, read it on its own terms. Its percentages cannot be compared directly with a UK label.

What to check before you buy.

• The recommended daily dose, and whether it suits your day.
• The amount and % NRV of the nutrients you care about.
• Overlap with anything else you take, so you do not double up.
• Allergens in the ingredients list, and suitability for your diet.
• Any health claims. The UK government's guidance for consumers says to "check that any health claims that you see on products are authorised health claims".

Where Immufix fits.

Immufix is one 25g scoop in around 200ml of water, once a day. Its claims follow the label rules above: only nutrients at 15% NRV or more carry one. Vitamin C, riboflavin, niacin, pantothenic acid, vitamin B6, folic acid and magnesium contribute to the reduction of tiredness and fatigue. Every amount and % NRV is on the science page, and we compare formats in powder or tablets.

The short version.

• A UK supplement label must say "food supplement" and state the recommended daily dose.
• Three statements are compulsory: do not exceed the dose, not a substitute for a varied diet, keep out of reach of young children.
• Each vitamin and mineral is shown per daily dose and as a % NRV. 15% is generally the minimum for a claim.
• Allergens are emphasised in the ingredients list. Best before is about quality, use-by about safety.
• US Supplement Facts panels use % Daily Value, which uses different reference amounts, so the percentages differ.

Food supplements should not be used as a substitute for a varied, balanced diet and a healthy lifestyle. If you have a medical condition, are pregnant, breastfeeding or taking medication, speak to your GP or pharmacist before taking any food supplement.