A number on a label without context is just a number. Thirty-six milligrams can sound like a little or a lot, depending on what you compare it with without thinking. The size of a number tells you nothing until you know what it refers to and which portion it is for.
Milligram, gram, microgram – putting the units in order
The amount of an ingredient is usually given in units of weight. A mistake of one step on the scale changes the meaning a thousand times.
| Unit | Symbol | Conversion |
|---|---|---|
| Gram | g | 1 g = 1000 mg |
| Milligram | mg | 1 mg = 1000 µg |
| Microgram | µg (sometimes mcg) | 1 µg = 0.001 mg |
| International unit | IU | The conversion depends on the substance and is not universal |
Two forms need attention. The microgram is sometimes written as “mcg”, and this is the same unit as µg. The international unit is not a unit of weight: it describes biological activity and has a different conversion for each substance.
So before you compare products, first change their amounts to the same unit. 500 µg and 0.5 mg are the same amount, although the first number looks more impressive.
The amount in the daily portion is the point of reference
The statement of quantity on the label refers to the recommended daily portion. This is the right point of reference. It is not the amount in the pack, and it is not the amount in a single capsule if one portion is several capsules.
The confusion comes from the front of the pack. It shows the largest number, and this is sometimes the total amount. The useful information is on the back.
Read more: How to read the ingredients of a food supplement – what to look at beyond the marketing name
Check how the portion is defined: a number of capsules, a scoop, a spoon or a measured volume of a liquid product. The rest of the calculation depends on this.
Read more: How to use liquid supplements without losing their properties
How to calculate the amount in the whole pack
The maths is simple: multiply the amount in one portion by the number of portions, and you get the total amount. It also works the other way round.
Here is an example calculation. The THESYBIN food supplement contains 3.38 mg of OLINATI.MED® in a daily portion of 6.5 ml, and a 195 ml pack contains 30 portions. The amount in the whole pack is 3.38 mg times 30, which is 101.4 mg.
The same amount in grams is 0.1014 g. None of these numbers is a judgement of the product. They are just different ways to write the same amount.
How many portions a pack really gives you
The number of portions tells you how long you can use the product and what it costs. A pack with 30 portions lasts 30 days if you take the product once a day.
People often make a mistake here when they compare prices. Two products with a similar price can have a different number of portions, so compare the cost of one daily portion.
Also check whether the volume of the pack divides evenly by the size of the portion, because in liquid products the last portion is sometimes not full.
Why more does not mean better
A bigger number on the label does not in itself tell you that a product has more value. The belief that more means better is one of the most common simplifications in this category.
For some ingredients, the link between the amount and the effect that researchers observe is not linear. For others, there are limits on the maximum amount in a product. A higher amount can also refer to a raw material with a different form or standardisation, so you cannot compare the numbers directly.
The most important reminder is on every food supplement label because it is required: do not exceed the recommended daily portion. This warning is not a formality. It is a condition for using the product as intended.
Also remember to add amounts together. If you take several products, the same ingredient can be in more than one of them, and the total amount can be higher than you expected. People who take medicines or have health problems should talk to a doctor or pharmacist about using supplements.
Upper safe levels of intake
For some nutrients, experts have set upper safe levels of intake. These are the maximum amounts at which healthy people are not expected to have side effects. The European Food Safety Authority carries out these assessments.
These values are not a target or advice. They are a limit that manufacturers and supervisory authorities use as a reference.
These values do not exist for all substances. If there is no value, this does not mean that the substance is harmless in any amount. It only means that no assessment has been done yet. A 2024 guidance document from an EFSA panel describes how these values are set.
The dose in studies and the dose in a product
Scientific publications give the amount used in a specific study, in a specific group of people and for a specific time. This is information about the conditions of the experiment, not advice for everyone.
Be careful when you compare such a value with the amount on a label. Studies use materials of different forms and purity. For complex raw materials, standardisation matters. For microbiological preparations, the described properties refer to a specific strain, not to the whole species.
So the statement “the study used X mg, the product contains Y mg” is not a conclusion in itself. For a useful comparison, you need to check whether both cases refer to the same material.
Reference intakes and when they apply
RI means reference intake. These are points of reference in the rules for an average adult. The label shows them as a percentage next to the amount in the daily portion.
They apply only in a limited way: RIs exist for vitamins and minerals, and the annex to Regulation (EU) No 1169/2011 lists these values. There are no RIs for plant extracts or microbiological preparations.
So if there is no percentage next to an ingredient, the manufacturer has not made a mistake. It means that no reference value exists for that substance.
Also, the RI is an average value for the population, not personal advice.
Three questions to ask yourself when you look at a dose
- What does this number refer to? The daily portion, one capsule or the whole pack. Without this, a comparison with another product tells you nothing.
- What unit is it in? Milligrams, micrograms and international units are three different scales.
- What exactly does the amount describe? Does the weight describe the raw material or the substance used for its standardisation? Is the ingredient described precisely enough to identify it?
Summary
A number of milligrams only has meaning in context: the unit, the size of the daily portion and the way the ingredient is described. To compare products, start by comparing the amounts in the daily portion.
A higher number is not an argument in itself, and you should not exceed the recommended daily portion.
Reference intakes help you understand the numbers, but only for vitamins and minerals. For other substances, you need to check what exactly the value refers to.
FAQ
Is 36 mg a lot?
You cannot answer this question without knowing the substance. The same weight means something different for an ingredient used in grams and for one given in micrograms. The point of reference is the specific ingredient, its form and the size of the portion.
Why is there no RI percentage for some ingredients?
Because reference intakes exist for vitamins and minerals. There are no such values for plant extracts and microbiological preparations, so the manufacturer has nothing to show.
Can I compare doses from scientific studies with the label?
Only carefully and after you check that it is the same material. The form of the raw material and the standardisation matter, and for microbiological preparations, so does the strain name.
Sources
- Regulation (EU) No 1169/2011 of the European Parliament and of the Council of 25 October 2011 on the provision of food information to consumers, including the annex that sets the reference intakes.
- Directive 2002/46/EC of the European Parliament and of the Council of 10 June 2002 on the approximation of the laws of the Member States relating to food supplements.
- Commission Regulation (EU) No 432/2012 of 16 May 2012 establishing a list of permitted health claims made on foods, other than those referring to the reduction of disease risk and to children’s development and health.
- EFSA Panel on Nutrition, Novel Foods and Food Allergens, Guidance for establishing and applying tolerable upper intake levels for vitamins and essential minerals, EFSA Journal, 2024, doi: 10.2903/j.efsa.2024.9052, and Scientific Committee on Food / EFSA, Tolerable Upper Intake Levels for Vitamins and Minerals, 2006.
- Regulation (EC) No 1925/2006 of the European Parliament and of the Council of 20 December 2006 on the addition of vitamins and minerals and of certain other substances to foods.