You're in the aisle again, two packs in hand, both shouting "bioavailable". It sounds important. It also sounds like a reason to pay more. Here is what the word actually means, and how to read it without getting sold a story.
The short answer
- Bioavailability is about how much of a nutrient your body can absorb and use from what you take.
- The form of a mineral or vitamin on the back of the pack matters more than a big front number.
- We use magnesium as bisglycinate. That is a formulation choice. It is not a claim that every other form is useless.
- A moderate amount of a named form can be a better label to trust than a megadose with no form named at all.
- Food still counts. A scoop sits beside the week, not instead of it.
What bioavailability means in plain words
If you take a nutrient, not all of it necessarily reaches the places your body can use it. Some passes through. Some needs converting first. Bioavailability is the share that is actually available.
That is why two packs can both say "magnesium 100 mg" and still not be the same object. One may name magnesium oxide. Another may name magnesium bisglycinate. Same mineral name. Different salt.
The useful habit is simple: turn the pack over and read the form in brackets, not only the nutrient name on the front.
Forms you will see, without the lecture
Magnesium. Oxide is common and cheap. Citrate turns up often when the gut is the point. Bisglycinate is magnesium bound to glycine. It is the form we use, and it is generally well tolerated. One of us also takes magnesium bisglycinate for her own sleep, and the sleep research for magnesium is still thin. Both of those are true at once. We would rather show you that than pick whichever sentence sells better.
B12 and folate. Labels may list cyanocobalamin or methylcobalamin, folic acid or a folate form. Those are different chemical forms. We do not turn that into a genetic lecture on a product page. If a clinician has named a specific form for you, follow that conversation, not a blog ranking.
Zinc and iron. Chelated forms (bound to amino acids, often ending in -glycinate) are common in newer formulas. Oxide forms are common in cheaper ones. Again: read the name. Do not assume a higher milligram line always means more of the mineral in use.
We do not print invented absorption percentages. Forms differ. The label should name them. That is enough for a shopping decision.
How to spot the form on a European label
Look for the nutrient, then the form beside it, then the milligrams or micrograms for a day's worth.
- Named form: bisglycinate, citrate, methylcobalamin, and so on.
- Amount per day, not per half-scoop or per "serving" you would never take alone.
- % NRV is an adult labelling ruler. Read the mg or µg first. Our label guide is here.
If the pack only says "magnesium" with no form, you cannot compare it fairly to one that names the salt.
Nutrients also share the queue
Some nutrients help each other. Vitamin C sits beside iron in many food conversations. Vitamin D and calcium are often discussed together. Others compete for the same pathways: zinc and copper is the example we wrote out in full on zinc and copper.
A long list of nutrients is not the same as a balanced list. A well-made multinutrient is partly about what was left out, not only what was piled in.
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Where My Daily Pocket fits
We name the forms on the label. Magnesium in our formulas is bisglycinate. Amounts in one daily scoop:
| Formula | Magnesium | Zinc | Vitamin D3 | B12 |
|---|---|---|---|---|
| Pocket Kids (4-11) | 100 mg | 5 mg | 25 µg | 25 µg |
| Pocket Teens (12-17) | 150 mg | 10 mg | 35 µg | 100 µg |
| Pocket Adults (18+) | 200 mg | 10 mg | 35 µg | 100 µg |
We contain no iron. If iron is the nutrient you actually need, this pouch is the wrong product. That conversation belongs with a GP.
More on magnesium amounts: How much magnesium does a child need?
FAQ
What does bioavailability mean?
How much of a nutrient from a food or supplement your body can absorb and use.
Does a higher dose always mean better absorption?
No. Form and dose are different questions. Read both.
Why do you use magnesium bisglycinate?
It is the form we chose. It is well tolerated. That is a formulation descriptor, not a ranking of every salt on the shelf.
Is bioavailability a reason to ignore food?
No. Food supplements should not replace a varied, balanced diet and a healthy lifestyle.
Sources
- EU Register of nutrition and health claims
- How to read a supplement label
- How much magnesium does a child need?
- Zinc and copper: why one goes missing
About the authors
Lina is a co-founder of My Daily Pocket and is certified in nutrition. Stanislava is a co-founder. They write the Knowledge Hub together.
Last reviewed: 15 October 2026.
Food supplements should not replace a varied, balanced diet and a healthy lifestyle. No supplement is a substitute for a varied, balanced diet. Stay within the dose on the pack. This page does not replace a GP. If you are pregnant, on medicines, or a child has a medical condition, speak to a professional.
Our first small release is complete and ordering is paused. Join early access for 10% off the first order from the next release. We will email the code when ordering opens.
