How to Read a Supplement Label (Line by Line)

July 20, 2026|Barry Lees

Hands examining the reverse of an unlabelled supplement bottle with reading glasses on cream linen

A supplement label has to carry a lot of legally required information in a very small space. The result is dense, unfriendly, and easy to skip — which suits some sellers perfectly well.

Here is what each part means, working through a typical UK label from top to bottom.

This is one of four guides supporting our main article on how to choose a supplement.

1. The product name and strapline

Not regulated in the way you might assume. A name can be almost anything, provided it does not present the product as a medicine.

That last part matters. A food supplement cannot legally be named or presented in a way that implies it treats a disease. Names containing words like "relief", "treatment" or a named medical condition sit in awkward territory — and yes, plenty of products on the market do exactly this.

The strapline underneath is often where an authorised claim appears — for example "for normal thyroid function". If it is legitimate, it will map to a specific nutrient in the panel below.

2. The claims block

Usually three or four ticked lines near the top of the information panel:

Vitamin C contributes to the normal function of the immune system
Zinc contributes to normal cognitive function

These are authorised health claims, and the wording is not chosen by the brand — it comes from the GB Nutrition and Health Claims Register. Companies must use the approved phrasing, or a close paraphrase with the same meaning.

Useful test: every claim should name a nutrient, and that nutrient should appear in the panel at 15% NRV or more. If a claim is attached to a herb rather than a vitamin or mineral, it is almost certainly not authorised.

3. The nutrition panel and %NRV

The core of the label. It should show each vitamin and mineral, the amount per serving, and the percentage of the Nutrient Reference Value.

Two things to watch:

Per serving, not per capsule. If a serving is three capsules, a pot of 90 lasts a month, not three. Comparing two products on price without checking serving size is how you end up paying more for less.

The 15% line. Below 15% NRV, a nutrient legally counts as present in an insignificant amount and cannot carry a claim. It can still be listed — it just cannot be sold to you as a benefit.

4. The "also provides" section

This is where botanicals, amino acids and other actives live — ingredients with no established NRV, so no percentage can be shown.

You will often see a double asterisk here, with a footnote reading "equivalent weight from extract". This one is worth understanding, because it is the single most misread number on any supplement label.

If a label says Turmeric Root** 4,800mg, that does not mean there are 4,800mg of turmeric in the capsule. It means the extract used is equivalent to that much raw root. A 10:1 extract at 480mg is stated as 4,800mg equivalent.

This is a legitimate, standard convention — concentrated extracts are genuinely stronger than raw powder. But it does mean headline numbers are not comparable unless you check the ratio. A product boasting "5,000mg" may contain 500mg of actual extract.

Where an extract is standardised, you will sometimes see the active named directly — for example "providing 10mg curcuminoids" or "standardised to 5% withanolides". That is the more informative figure, and a good sign.

5. The full ingredients list

Legally required, in descending order by weight. This is the most honest part of any label, because the order cannot be arranged for effect.

If a bulking agent appears first, it is the largest component. Common ones are brown rice flour, maltodextrin and microcrystalline cellulose. Their presence is normal — capsules need filling — but position tells you something.

The capsule shell is an ingredient too. HPMC (hydroxypropyl methylcellulose) is plant-based and suitable for vegans. Gelatin is animal-derived and is not. This is a common trap: a product can be full of plant ingredients and still not be vegan because of the shell.

6. Allergens

UK law requires the 14 major allergens to be emphasised in the ingredients list, usually in bold or capitals. Look for a separate ALLERGY ADVICE line too.

Supplement allergens are often not the ones you would guess:

Crustaceans — glucosamine is frequently shellfish-derived
Fish — marine collagen, omega-3, krill
Soy — lecithin, phosphatidyl serine, natto, isoflavones
Gluten — barley and wheat grass in greens powders
Milk — whey, and some probiotic culture media
Celery — celery seed in herbal diuretic blends
Sulphites — occur naturally in some plant extracts

Also read the "manufactured in a facility that also handles..." line. That is precautionary rather than a declared ingredient, but if your reaction is severe it is the more important sentence.

7. Directions and warnings

Read these before buying, not after.

Genuine warnings that appear on UK labels include: not suitable during pregnancy or breastfeeding; interactions with blood-thinning or blood-pressure medication; caution with epilepsy; do not take if peptic ulcers are present; and choking risk for glucomannan products, which swell on contact with liquid and must be taken with plenty of water.

Caffeine content should be declared where relevant, and it appears in more products than people expect — guarana, green tea and "thermogenic" blends all contribute.

8. The small print at the bottom

Easy to skip, but this is where accountability lives:

Company name and full address — legally required. Its absence is a serious warning sign.
Batch number and best before date — usually on the base. Needed for traceability if anything goes wrong.
Country of manufacture — "Made in the UK" and "Packed in the UK" are not the same thing.
Storage instructions — and for live cultures or oils, these actually matter.