Reading a Supplement Label Like a Scientist

A good supplement label should let you answer a few basic questions quickly: What is the product? What does one daily portion provide? Which ingredients are present? What warnings apply? And which statements are authorised claims rather than marketing language?

1. Start with the Legal Name

“Food supplement with vitamin D” or “food supplement with magnesium” tells you what type of food the product is and which nutrients or substances characterise it. A brand name such as “Daily Energy” is not a substitute for the legal description.

2. Find the Recommended Daily Dose

Compare products by the recommended daily portion, not automatically by one capsule or one scoop. A bottle may contain 60 capsules but require two capsules per day. The composition table should state the amount delivered by the recommended daily dose.

3. Read the Amount and Unit

Milligrams (mg) and micrograms (µg) are not interchangeable: 1 mg = 1,000 µg. This matters for nutrients such as vitamin D, vitamin B12, folate, selenium and iodine.

4. Understand %NRV

NRV means Nutrient Reference Value. The percentage shows how the daily portion compares with an EU reference value for labelling. It is not a personalised target, a treatment dose or a score of product quality.

5. Check the Ingredient Form

The front may say “magnesium,” while the ingredient list identifies magnesium bisglycinate, citrate or oxide. The composition table should show the amount of elemental magnesium, not only the weight of the compound. Similar details matter for folate, iron, zinc, selenium and botanical extracts.

6. Read Ingredients in Order

Ingredients are generally listed in descending order by weight at manufacture. Additives should be identified by function and name or E-number, and allergens must be emphasised.

7. Separate Claims from Medical Promises

An authorised claim might say that vitamin C contributes to the normal function of the immune system. That is different from claiming that a product prevents flu or treats an infection. Food supplements cannot be advertised as preventing, treating or curing disease. Botanical products require particular care: a familiar plant name does not automatically give the seller permission to claim improved memory, hormone balance, anxiety relief or pain treatment.

8. Read the Warnings

Common supplement warnings include not exceeding the recommended daily dose, keeping the product away from young children and not using supplements as a substitute for a varied diet and healthy lifestyle.

9. Check Net Quantity, Lot and Date

The pack should identify the quantity, such as the number of tablets, net weight or volume. The lot number supports traceability. The best-before date tells you how long the unopened product is expected to retain its specified quality.

10. Expect the Same Information Online

For a prepacked food sold online in the EU, nearly all mandatory food information must be available before the purchase is completed; the best-before date can follow at delivery.

A Quick Checklist

Before buying, ask: Is the daily dose clear? Are active amounts stated per daily dose? Are vitamins and minerals shown with %NRV? Are ingredient forms and allergens visible? Are benefit statements tied to an authorised nutrient claim? Are warnings and responsible company details easy to find?

Related: browse All Products to compare labels for yourself, or check our FAQ page for common labelling questions.

General information only; not medical advice.

Further reading: Food Information to Consumers Regulation | EU Register of Health Claims