How to read a dietary supplement label
Turning the bottle over, are you faced with a list of complicated names, milligrams, and percentages? Yet, a dietary supplement label contains everything you need to know to make the right choice, provided you know where to look.
At Pure Lab Nutrition, we believe that an informed consumer makes better choices. Here is your guide to deciphering a label in a few minutes, with a step-by-step method, the most common pitfalls, and answers to your questions.
📑 Table of Contents
- Mandatory information
- The daily serving, the most important line
- The list of ingredients
- Claims: what is authorized
- Bioavailability: why form matters more than quantity
- The 5-step method
- Warning signs
- Common reading errors
- Frequently asked questions
- In summary
Mandatory information
According to the DGCCRF, a dietary supplement label must include, among other things:
- the designation "dietary supplement"
- the names of the nutrients or substances that characterize the product
- the recommended daily serving
- a warning to not exceed the daily dose
- a statement that the product should not be used as a substitute for a varied diet
- a statement to keep the product out of reach of young children
- the list of ingredients, allergens, net quantity, best-before date, and the name and address of the responsible party
💡 Why these details matter
They are not just formalities. The term "dietary supplement" reminds you that this is not a medicine. The warning about the daily dose protects you from overdosing. And the name of the responsible party allows you to know who to contact if you have any questions. If any of this information is missing, it is a first sign of caution.
The daily serving, the most important line
Unlike food products, which are labeled per 100g, supplements indicate their content per daily serving. This is the table you should look at first.
📊 How to read it
| Column | What it tells you |
|---|---|
| Quantity (mg, µg) | How much of the nutrient you are actually taking per day |
| % NRV | The portion of Nutrient Reference Values covered by the serving |
| Form | For example: bisglycinate, citrate, methylcobalamin—the chemical form of the nutrient |
Pay attention to units: 1 mg = 1,000 µg. And for a mineral, look at the amount of elemental mineral, not the total weight of the compound: in a zinc bisglycinate, for example, the zinc represents only a portion of the weight, the rest being the glycine it is bound to. A good label clearly indicates the quantity of zinc provided.
🧪 Why form matters
The same nutrient exists in several forms, which do not all have the same tolerance or absorption. For zinc, a study published in 2007, for example, compared the absorption of bisglycinate and gluconate. For B12, methylcobalamin and cyanocobalamin do not have the same structure. To learn more, read Zinc bisglycinate, gluconate, citrate: which form to choose? and What is the best form of magnesium?
The list of ingredients
Ingredients are listed in descending order of weight. You will find the active ingredients there, but also:
- the capsule shell (plant-based or animal-based)
- bulking agents and anti-caking agents, which allow the product to be manufactured
- any flavorings, sweeteners, or colorings
For a plant, check if it is a standardized extract (e.g., "standardized to 5% withanolides"): this is a guarantee of consistency from one batch to the next. Also check the part of the plant used (root, leaf, etc.) and the quantity of extract per serving. Our Organic Ashwagandha, for example, indicates KSM-66 root extract standardized to 5% withanolides, at 300 mg per capsule. Read Ashwagandha KSM-66: why the extract matters.
🌱 Vegan, gluten-free, organic: where to see it?
This information is generally found near the list of ingredients or on the front of the packaging. For a vegan diet, specifically check the capsule shell and the origin of the active ingredients: marine collagen, for example, is by nature animal-derived. Allergens must be highlighted in the list of ingredients.
Claims: what is authorized
In the European Union, health claims must be authorized. Regulation (EU) No 432/2012 sets the list: for example, "magnesium contributes to a reduction of tiredness and fatigue" or "vitamin C contributes to the normal function of the immune system." The DGCCRF reminds us that a supplement cannot:
- claim to prevent, treat, or cure a disease
- refer to the rate or magnitude of weight loss
- suggest that a balanced diet is not sufficient
Remember the standard formula: "contributes to...". For most plants, no claims have yet been authorized at the European level: be wary of a herbal product that makes precise promises.
Bioavailability: why form matters more than quantity
A label might display an impressive dose of magnesium or zinc, and yet the body will only absorb a fraction if the chemical form is poorly chosen. This is the concept of bioavailability: the proportion of the ingested nutrient that actually reaches the bloodstream and the cells.
🔹 The example of magnesium
Magnesium oxide is one of the least well-absorbed forms and can cause digestive discomfort. Magnesium bisglycinate and citrate offer better tolerance and absorption. Yet, the dose displayed in mg may be identical, or even higher for the oxide. What the label doesn't always announce is what the body actually retains.
🔹 The example of zinc and iron
Zinc bisglycinate, compared to gluconate in a study published in 2007 (Gandia et al.), showed superior absorption. For iron, vitamin C taken simultaneously increases non-heme iron absorption—which is why some formulas already include it. These data can be read directly on the label if the brand is transparent about its forms.
🔹 What this changes in practice
Two products with identical 15 mg zinc doses can have very different effects depending on their form. Prioritize a product that specifies the form (bisglycinate, picolinate, citrate, etc.) rather than just a simple "zinc 15 mg" without further indication. Our Zinc Bisglycinate specifies its form and its dose of elemental zinc per serving for direct and transparent comparison.
👉 Discover our Zinc Bisglycinate here.
The 5-step method
1️⃣ Identify the need: what are you really looking for? Does the product address it?
2️⃣ Read the daily serving: how many capsules, and what quantities per day?
3️⃣ Check the forms and standardization: are they specified?
4️⃣ Browse the ingredient list: shell, additives, allergens
5️⃣ Read the usage precautions: people for whom the product is not recommended, duration of use, instructions for use
Warning signs
❌ Spectacular promises: "-5 kg in 10 days," "cures insomnia"
❌ Vague composition or "proprietary blends" without quantities
❌ No name or address of the responsible party
❌ Very high doses without justification
❌ A product purchased outside of usual distribution channels
✅ Conversely, a detailed composition, precise forms, and measured claims are good signs. And if you take several products, add up the quantities: read Can you take several supplements at the same time?
Common reading errors
✅ Reading the quantity per capsule instead of the quantity per daily serving (or vice versa)
✅ Confusing mg and µg, a thousand-fold difference
✅ Believing that a high % NRV is necessarily better: what matters is your actual need and your other intakes
✅ Ignoring chemical forms: preferring a bisglycinate to an oxide, or a methylcobalamin to a cyanocobalamin, can make a real difference in tolerance and absorption
✅ Ignoring usage precautions, often written in small print on the back
✅ Relying only on the front of the packaging, which highlights marketing rather than composition
Frequently asked questions
❓ What does "NRV" mean?
These are Nutrient Reference Values, European benchmarks for labeling. The % NRV indicates what portion of this benchmark the daily serving covers.
❓ Is an NRV % above 100% dangerous?
Not necessarily: some nutrients are commonly offered above 100% of NRVs. However, you must take into account all of your intakes (food and other supplements) and never exceed the indicated daily serving.
❓ Can a supplement be consumed after the indicated date?
This is a best-before date: beyond this, the content of certain nutrients may have decreased. It is better to respect this date and keep the product away from heat and humidity.
❓ Why are there additives?
Bulking or anti-caking agents are used to fill capsules uniformly and to prevent powder from sticking. They are authorized and appear in the list of ingredients. Our Dietary Supplement Glossary helps you decipher other terms.
❓ How to compare two products based on the same plant?
Look at three points: the part of the plant used (ashwagandha root is the study reference, not the leaves), the type of extract (KSM-66, Sensoril, etc.) and its standardization (% of withanolides or other active principles), and the dose of extract per serving. Without this information, comparison is impossible.
In summary
1️⃣ Look first at the daily serving and the quantities
2️⃣ Check the form of the nutrients and the standardization of plants: bioavailability takes precedence over gross dose
3️⃣ Claims must be authorized and measured
4️⃣ Be wary of miracle promises and read the usage precautions
Pure Lab Nutrition ... The art of nourishing your well-being.
Sources:
- DGCCRF. Labeling, presentation, and advertising of dietary supplements: rules to know. economie.gouv.fr
- Regulation (EU) No 432/2012 regarding authorized health claims. EUR-Lex
- Gandia P. et al. (2007). A bioavailability study comparing two oral formulations containing zinc (Zn bis-glycinate vs. Zn gluconate) after a single administration to twelve healthy female volunteers. International Journal for Vitamin and Nutrition Research, 77(4):243-248. PubMed
Restez informé 🌿
Recevez nos derniers articles et conseils santé directement dans votre boîte mail.
