How to read a supplement label

Published: 20 June 2026 · Updated: 12 August 2026

The label is the most honest part of a supplement. The advertising may be beautiful, but the truth always sits in the small print. Here is how to read it.

Serving size — the key figure

Every amount on a label refers to a serving, not to a capsule. If a serving is three capsules and the pack holds 30, the product lasts ten days, not a month. That is the most common mistake when comparing prices.

The NRV percentage

Next to vitamins and minerals you find a percentage of the NRV — the European nutrient reference value. 100% means the serving covers the daily reference amount.

A figure of 500% or 1000% is not automatically better. Excess water-soluble vitamins are excreted; fat-soluble ones accumulate.

Extract standardisation

Next to a plant extract you often read something like: "turmeric extract 10:1, standardised to 95% curcuminoids". The 10:1 means one gram of extract comes from ten grams of raw material. The "95%" tells you the share of the active compound.

If that information is missing, you cannot tell how strong the extract is.

Excipients

Magnesium stearate, silicon dioxide, microcrystalline cellulose — these are technological components needed for manufacturing. Their presence is normal and not a danger sign.

Allergens and origin

This is the most important line for anyone with an allergy.

• Glucosamine — often from shellfish shells
• Chondroitin — from bovine or fish cartilage
• Propolis and wax — bee products
• Gelatin capsule — of animal origin
• Omega-3 — fish or algae

What should be there but often is not

The manufacturer’s full name and address, importer details, batch number, expiry date and storage conditions. If any of those is missing, that is a separate question to ask about the product.

What the percentage on a label means

A percentage often stands next to vitamins and minerals — it is the share of the reference daily intake, that is, how much of the guideline figure for an average adult one serving covers. That figure is an average and does not account for pregnancy, age, chronic conditions or medicines being taken.

The practical conclusion is simple: 500% does not automatically mean "five times better". Excess water-soluble vitamins are excreted, fat-soluble ones accumulate — and it is in the second case that it matters not to let the same substance add up when several supplements are taken in parallel.

Excipients and the capsule shell

After the active components, the ingredient list gives what has a technological purpose: magnesium stearate and silicon dioxide serve the manufacturing process, cellulose is a filler. This is a normal part of the list and is not in itself a marker of quality — neither good nor bad.

The capsule shell, on the other hand, makes a practical difference: gelatin is of animal origin, HPMC is plant-based. If your diet is restricted or you have an allergy, that is exactly the line to read. The allergen warning usually sits right there too — traces of milk, soy, fish or nuts.

How to compare two labels with each other

Comparing two products by the price of the pack is almost always misleading. The right unit is the cost of one day: divide the price of the pack by the number of days it lasts at the dose stated on the label. A more expensive pack often turns out cheaper per day.

The second unit is the cost of the active substance. If one product has 500 mg per serving and another 250 mg, then two capsules must be compared with one, not capsule with capsule. It is only after these two calculations that it becomes visible which offer is genuinely better value.