Magnesium supplements: how the illusion of a "strong product" is created

"Oh, your magnesium is very weak. Only 100 mg per capsule. I take 600."

I hear this sentence often. And it was precisely this that made me stop and write what you are now reading.
Magnesium is one of the most important minerals in the human body. Its deficiency can be both the cause, the consequence, and a constant companion of many acute and chronic health problems. Therefore, it is very important not just to take magnesium, but to take it in the right form and at the right dose.
And here arises the first important point.

Not all "magnesium" is created equal

More precisely, not all forms of magnesium are equal.
Different magnesium salts:

  • are absorbed differently; 
  • are tolerated differently; 
  • may have different effects. 

Therefore, both a doctor recommending and a person choosing a supplement must know what they are actually consuming. An unexpected effect often leads not only to disappointment but sometimes to real harm to health, as the problem remains unresolved.
How to avoid this?

Know how to read labels

On packaging, we can find the inscription: magnesium bisglycinate – 600 mg. The natural conclusion is that this is 600 mg of magnesium. However, this is not true. This is the total amount of the compound (salt), not elemental magnesium – the one the body needs. In reality, such an amount provides about 60–70 mg of magnesium.

How to understand this more simply?
Similar to regular salt. If you have 10 g of salt, that's not 10 g of sodium. That's 10 g of sodium chloride, in which sodium is only about 40%. The same applies to magnesium supplements.

What must be indicated on the label?

According to EU requirements, magnesium food supplement labels must indicate:

  • the amount of elemental magnesium;
  • the amount in the recommended daily dose;
  • the percentage of the nutrient reference value (NRV).

Important: The NRV for magnesium is 375 mg per day.

Where to find the actual amount of magnesium?

It is usually not written in large letters on the front of the package.
The actual amount of magnesium is provided:

  • in a table (nutrition or composition);
  • with the NRV percentage indicated next to it.

E.g.: Magnesium – 100 mg (27% NRV)
This is precisely the actual amount you receive.

A very important nuance: dosage

The NRV percentage is indicated for the recommended daily dose, not for a single capsule.
This means that often you need to take 2, 3, or even 4 capsules/tablets to reach that recommended amount, so it is essential to pay attention to:

  • how many capsules make up the daily dose;
  • how much magnesium you actually get.

Second, more complex matter

There is another topic that requires a bit more understanding.
Some forms of magnesium are expensive. The cost of quality raw materials can be several times higher than the price of some of the cheapest magnesium supplements for the end consumer. One such example is magnesium bisglycinate. This is a well-absorbed form with high bioavailability. Meanwhile, magnesium oxide is one of the cheapest forms, with a bioavailability of only a few percent. Therefore, in practice, it is often done simply: bisglycinate is mixed with oxide to reduce the price. This in itself is not a problem – if it is clearly and transparently stated in the composition. In such a case, the consumer knows that they are consuming a mixture of different forms of magnesium. The problem arises when this is "forgotten" to be mentioned.

How to understand for yourself that a product is not what it seems?

This requires a bit of mathematics.
The amount of magnesium in magnesium bisglycinate:

  • theoretically reaches about 14 percent;
  • in reality – about 11–12 percent.

If you see on the label, for example:

  • elemental magnesium – 100 mg 
  • magnesium bisglycinate – 500 mg 

You can calculate:
100 / 500 × 100 = 20 %

In such a case, the resulting number exceeds even the theoretical limit. This means it cannot be pure magnesium bisglycinate. It is very likely that the product also contains other forms of magnesium, most often magnesium oxide – even if this is not explicitly stated.

How many such products are on the market?

Many. These are not isolated cases.

Why is this allowed?

The control system operates according to established principles. It checks whether the mandatory data is provided on the label and whether general requirements are met. However, a detailed analysis of the composition of every product is not carried out constantly – simply because the market is huge, and there are thousands of products. Usually, reactions are to specific complaints.

What does this mean for the consumer?

This means that responsibility partly lies with the consumer. Magnesium is important, but even more important is to understand what you are consuming. Therefore, before drawing conclusions, it is worth:

  • checking how much elemental magnesium there is;
  • assessing how many capsules make up a daily dose;
  • and, if necessary, simply recalculating and checking.

In conclusion

Reading a label is simple, but understanding it requires effort. But perhaps it's worth delving deeper to see if we are actually solving a problem or just creating the illusion of solving it?
If this information was useful, please share it – it is very likely that someone near you today still thinks they are "taking 600 mg of magnesium in one tablet."

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