How to read a food supplement label: what it must say and what to look for

The label on a food supplement tells you what it is, how much to take a day, how much of each nutrient it provides and which warnings to bear in mind. Almost everything on it is required by EU law ^1 2. If you know where to look, it takes you a minute to tell a well-labelled product from one that is not.

In five steps

How to read a supplement label

What a food supplement is (and what it is not)

A food supplement is a food. Its purpose is to supplement the normal diet with a concentrated source of nutrients or other substances with a nutritional or physiological effect, in dose form: capsules, tablets, sachets or powder to be measured out ⁶.

It is not a medicine. It is not intended to prevent or treat diseases, and its label may not attribute that property to it ^1 6.

Nor does it go through an authorisation process like the one for medicines. In Spain, the company must notify the authorities of each product, with a copy of its label, before or at the same time as it goes on sale ^5 6. What is regulated is which vitamins and minerals it may contain, in which forms, and what the label may say ⁶.

What the label must say by law

Two sets of rules apply together. The one on food supplements sets out what is specific to these products, and the one on food information sets out what all prepacked foods must carry ^1 2. In Spain, Royal Decree 1487/2009 contains the same requirements ⁵.

The three warnings are compulsory on every supplement ¹:

• Do not exceed the stated recommended daily dose.
• Do not use as a substitute for a balanced diet.
• Keep out of the reach of young children.

If a label is missing any of them, or does not say “food supplement” anywhere, you already have a first reason to be wary.

The daily dose: all the figures refer to it

In a supplement, amounts are not given per 100 g, as they are for other foods. They are given per daily dose recommended by the manufacturer, and always in figures ^1 5.

So the first thing to do is find that dose: 2 capsules, 1 scoop of 3 g, 3 softgels, 25 g of powder. If the table says “per 2 capsules” and you take one, you get half of everything.

Also check how many doses the pack contains. It tells you how long it will last and how much it costs you each day. A bottle of 120 capsules at 2 capsules a day lasts 60 days.

Something that may surprise you: supplements do not have to carry the table of calories, fat, carbohydrates and protein that other foods have ². Some products include it anyway, especially powders that provide energy, such as a protein or a hydration drink.

The % NRV: what it means and why it can be over 100%

Vitamins and minerals are declared as an amount and also as a percentage of the NRV, the nutrient reference value ¹. It is the daily reference amount for an adult, set in the EU regulation on food information ².

Two examples with real figures:

• Magnesium: the NRV is 375 mg. A dose with 200 mg provides 53% ².
• Vitamin B6: the NRV is 1.4 mg. A dose with 6 mg provides 429% ².

A % NRV above 100 does not mean the product is dangerous. The NRV shows what you need, not how far it is safe to go. For safety, the reference is the tolerable upper intake level: the highest daily amount considered safe in the long term. For vitamin B6, EFSA sets it at 12 mg a day for adults, including pregnant and breastfeeding women ⁷. Those 6 mg are half of it.

Some substances have no NRV, such as creatine, omega-3, amino acids or melatonin. For these you will only see the amount. You will find these and other label terms in the glossary.

Compound and nutrient: not the same thing

Many minerals and vitamins are bound to another molecule, which helps them keep or be absorbed. The table of amounts must give you the milligrams of the nutrient ¹, but you will often see those of the compound as well, in the table itself or in the ingredients. What counts is the nutrient.

• 1,000 mg of magnesium bisglycinate provides 200 mg of magnesium.
• 7.3 mg of pyridoxine hydrochloride provides 6 mg of vitamin B6.

Each form provides a different proportion of the mineral: a gram of magnesium oxide is not the same as a gram of bisglycinate. We compare them form by form in which magnesium to take.

Something similar happens with omega-3: what matters is the milligrams of EPA and DHA, not those of the oil in the softgel. We explain how to read it in which omega-3 to buy.

The list of ingredients

This is where everything in the product appears, in descending order of weight: what comes first is what there is most of ². It includes the main ingredient, the capsule or softgel and the additives, such as flavourings, sweeteners or anti-caking agents, which stop the powder from clumping.

Allergens must be emphasised with a typeface that sets them apart from the rest, for example in bold ². If you have an allergy or intolerance, this is the first thing to check.

Two practical details:

• A vegetable capsule or a gelatine softgel decides whether the product is suitable for vegans. Check what it is made of.
• Flavourings and sweeteners are usually found in flavoured products. If you would rather avoid them, look for the unflavoured version.

Health claims: which ones are allowed

Statements such as “Magnesium contributes to normal muscle function” are health claims. In the European Union, only claims that are authorised and included in an official list may be used, with their wording and their conditions of use ⁴.

When a label uses one of them, it must be accompanied by ⁴:

• The importance of a varied and balanced diet and a healthy lifestyle.
• The amount and pattern of consumption needed to obtain the effect.
• Where needed, who it is not recommended for and a warning about excessive consumption.

And there are things the law does not allow it to say ^1 4:

• That the product prevents or treats a disease.
• That a balanced diet does not provide enough nutrients.
• That your health could suffer if you do not take it.
• The rate or amount of weight you will lose.
• That it is recommended by a particular doctor or other health professional.

Date, batch and storage

“Best before…” is the date of minimum durability: how long the product keeps its properties if you store it properly ². It is the one you will see on most supplements. The “use by” date is something else: it is used on highly perishable foods, which are no longer considered safe after that date ².

The batch, or lot, identifies the group of packs made under the same conditions. It is usually preceded by the letter “L” and is set by whoever manufactures or packs the product ³. If anything ever has to be checked or recalled, the batch tells you exactly which packs are affected. Every Nutri Gains tub and bottle carries its own: we tell you how we work in quality and manufacturing.

Storage conditions are also compulsory where they are needed ². Pay particular attention to what happens after opening: some products have to be kept in the fridge or used up within a few weeks.

Signs that should make you think twice

With all of the above in mind, these are the clearest warning signs:

1. It does not say “food supplement”, or the daily dose or the warnings are missing ¹.
2. You cannot see in figures how much of each nutrient or substance it contains per daily dose. A “blend” with no amounts does not let you know what you are taking ¹.
3. It promises to prevent or treat a disease, or quotes a number of kilos you will lose ^1 4.
4. It says that food is not enough or that your health needs it ^1 4.
5. It recommends taking more than the dose or combining several doses to notice the effect.
6. The amounts go over the tolerable upper intake level of a nutrient, especially if you already take other supplements with the same one. For magnesium, you will find it in how and when to take magnesium.

If you are unsure about a product or about how to combine several, see where to begin in which supplements should I take. And if you are pregnant or breastfeeding, take medication or have a medical condition, check with your doctor before you start.

An example: the label of our magnesium

This is how to read what the 2 daily capsules of our Magnesium Bisglycinate + B6 provide:

• The daily dose is 2 capsules, and all the figures refer to them.
• The compound is magnesium bisglycinate, 1,000 mg; the nutrient, 200 mg of magnesium, 53% of the NRV.
• Vitamin B6 comes to 6 mg, 429% of the NRV: half of EFSA's tolerable upper intake level ⁷.
• Its claims are authorised and come with their statement on diet: “Magnesium contributes to normal muscle function” and “Vitamin B6 contributes to normal psychological function”. A varied and balanced diet and a healthy lifestyle are important.