How to Read a Supplement Label Without Getting Lost
Serving size, percentage daily value, and the difference between the ingredient and the compound it comes in. A short guide to the numbers on the back of the pack.
Two products can look identical on the front of the pack and be quite different on the back. The label tells you what you are actually buying, once you know which numbers matter.
Start with the serving size
Every other number on the panel refers to one serving. If a label lists 500 mg of vitamin C per serving and the serving is two tablets, a single tablet gives you 250 mg. Comparing two products without checking this is the most common mistake people make.
The amount per serving
This is the number that matters most. It tells you how much of each nutrient one serving contains, usually in milligrams (mg) or micrograms (mcg). Note that 1000 mcg equals 1 mg, which is why a figure like 5000 mcg of biotin can look far larger than it is.
Percentage of daily value
Where shown, this compares the amount in a serving against a general daily reference intake for an average adult. It is a rough guide, not a personal target. Requirements vary with age, pregnancy, diet, and health status.
A very high percentage is not automatically better. For some nutrients, particularly fat-soluble vitamins such as A, D, E, and K, more is not harmless, because the body stores rather than excretes the excess.
Look at the form, not just the name
Minerals are attached to other molecules to make them stable, and the label usually names that compound. Magnesium glycinate, magnesium citrate, and magnesium oxide all deliver magnesium, but they differ in how well they dissolve and how they tend to sit with people.
The same applies to the elemental amount. A tablet listing 500 mg of magnesium citrate does not contain 500 mg of magnesium, because part of that weight is the citrate. Good labels state the elemental amount separately.
The other ingredients line
Below the nutrient panel you will find binders, fillers, flavourings, and sweeteners. This is where to look if you avoid particular additives, or if you have an allergy.
What is not on the label
A label tells you what is in the product. It cannot tell you whether you personally need it. Blood tests, diet, and a conversation with a doctor or pharmacist do that. If you already eat a varied diet, you may be getting enough of a nutrient without supplementing it at all.
This article is general information about nutrition, not medical advice. Food supplements are not intended to diagnose, treat, cure, or prevent any disease. If you are pregnant, breastfeeding, taking medication, or managing a health condition, speak to your doctor or pharmacist before starting a supplement.
