How to read a supplement label without getting fooled
There are only three numbers on a supplement label that decide whether it's worth it: how much active ingredient there is per serving, how many servings the container holds and what percentage of the reference value that serving covers. The size of the bottle, the number of ingredients and the words on the front are decoration.
This guide isn't about which supplement to take. It's about how to look at any of them and leave the aisle knowing what you're buying.
1. Everything is measured per serving, never per container
It's the oldest trick and the one that works best. The front shouts "1,500 mg of turmeric". You turn the bottle around and the panel says: "Serving size: 3 capsules". In other words, 500 mg per capsule, and the 90-capsule bottle lasts 30 days, not 90.
The first line to look for is always the one that defines the serving: "per capsule", "per 2 capsules", "per scoop". Everything else in that column refers to that amount.
2. The daily dose versus the dose used in studies
An ingredient can be present and still be irrelevant. If research on a substance uses 400 mg a day and the product provides 40 mg, the ingredient is on the label for you to read, not to have an effect. The industry calls it fairy dusting: sprinkling in a tiny bit.
You don't need to know every dose. It's enough to be wary of labels with twenty active ingredients in a single capsule: they can't fit in useful amounts.
3. Proprietary blends hide the amounts
When you see "Proprietary blend 745 mg" followed by a list of twelve plants, what they're telling you is that the twelve add up to 745 mg, but not how much there is of each. 95% of it could be the cheapest ingredient on the list.
It's legal and sometimes there's a genuine commercial reason for it. But as a buyer, it's information you don't have. If two products are similar and one breaks down every amount, that one is giving you something the other withholds.
4. Extract ratios: what 30:1 means
With botanicals you'll see figures like "Shilajit extract 30:1, 400 mg" or "standardized to 40% polysaccharides". They're two different things:
- The ratio (30:1) tells you how much raw material was concentrated: 30 kg of plant to obtain 1 kg of extract. It's a measure of concentration, not of quality or guaranteed potency.
- Standardization (40% polysaccharides) is more informative: it guarantees the extract contains at least that proportion of the compound that matters. It's what lets you truly compare two bottles.
Between a product with a ratio and one that's standardized, the second tells you more.
5. The NRV and what 100% means
The %NRV (nutrient reference value) shown next to vitamins and minerals compares the dose with a European reference for the general adult population. It's neither a personal recommendation nor an upper limit.
A 1,000% NRV isn't automatically bad —it's common with vitamin D, for example— nor automatically better. What is worth avoiding is stacking without noticing: a multivitamin plus a specific product plus a fortified food can add up to more than you think.
6. The chemical form changes the result
Two products with "500 mg of magnesium" can deliver very different amounts of actual magnesium depending on the salt they use. The same goes for iron, zinc or vitamin E. The form always appears in brackets in the ingredient list: "Magnesium (as magnesium oxide)", "Iron (as ferric saccharate)".
It's the detail that separates an honest label from a cosmetic one. We go into it in the guide to magnesium forms.
7. Excipients: which ones are normal
Almost no supplement is just the active ingredient. It needs something to form the capsule and something that allows it to be manufactured. These are normal and shouldn't alarm you:
- Hypromellose or pullulan: the vegetable capsule.
- Magnesium stearate, silicon dioxide: anti-caking agents, in minimal amounts.
- Microcrystalline cellulose, rice flour: fillers that give the capsule volume.
What does deserve a look is a powder whose ingredient list starts with maltodextrin or sugar: there the filler isn't functional, it's weight.
8. Which seals mean something
Many icons on labels are the manufacturer's own claims: "natural", "premium", "high absorption" aren't regulated. These three do involve external verification:
- GMP (Good Manufacturing Practices): certifies the plant's process, not the specific product.
- IFOS: independent testing specific to fish oils, with a public report per batch.
- Informed Sport / Informed Choice: testing for banned substances, relevant if you compete.
And a fourth that isn't a seal but a document: the batch's certificate of analysis (COA). A brand that publishes it is showing its homework.
9. What the law allows to be said
In the European Union, a supplement can only be linked to a benefit if that benefit is on the list of authorized claims in Regulation (EU) 432/2012, and with very specific wording. That's why serious labels sound so neutral: "iron contributes to the reduction of tiredness and fatigue", "zinc contributes to the normal function of the immune system".
Those flat sentences are a good sign. When a label promises that a product "fights", "prevents", "cures" or "reverses" something, or uses far more enthusiastic language than its competitors for the same ingredient, it's going beyond what it can prove.
Watch out for the opposite nuance: an ingredient not having an authorized claim doesn't mean it's useless. Many botanicals —functional mushrooms, ashwagandha, shilajit— are still pending evaluation in the EU. It means nobody can promise you a specific effect, and an honest brand will tell you so.
10. Cost per serving
It's the last calculation and the one that saves the most money. Divide the price by the actual servings in the container, not by the capsules. A 120-capsule bottle at two per serving costs twice as much per day as a 120-capsule bottle at one per serving, even if the bottle price is the same.
The summary: seven questions
- How much active ingredient is there per serving?
- How many actual servings does the container hold?
- Is the amount of each ingredient listed, or is there a proprietary blend?
- What chemical form does it use?
- Is the extract standardized to anything?
- Is there external verification or just icons?
- How much does it cost per day?
Frequently asked questions
What does NRV mean on a supplement label?
It's the nutrient reference value: it compares the amount of a vitamin or mineral per serving with an EU reference for adults. 100% isn't a personal recommendation or an upper limit.
What is a proprietary blend?
It's a group of ingredients where only the total weight is listed, not how much of each. It's legal, but it keeps you from knowing whether each ingredient is present at a useful amount.
How do you work out the cost per serving of a supplement?
Divide the price by the number of real servings, not the number of capsules. If one serving is two capsules, a 120-capsule bottle gives you 60 servings.
How we apply it at Ivalro
This is the filter we use to choose what goes into Ivalro, and that's why the catalog is short. You can see how it's applied in vitamins and minerals and in functional mushrooms, where each product page shows the dose per serving and the standardization where there is one. If you still have questions, check our FAQ.
Magnesium GlycinateLists elemental magnesium per dose.View product →
Lion's ManeStandardized to 40% polysaccharides.View product →
These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease. Dietary supplement. Not intended to replace a varied and balanced diet or a healthy lifestyle. Do not exceed the recommended daily dose.
Ivalro editorial team. Written from EU regulations and published scientific sources, linked below. Last reviewed: October 2026. For information only: not a substitute for advice from a healthcare professional.