Multivitamin 2026: the 4 criteria that change everything

You stand in front of the "dietary supplements" aisle at the pharmacy or on a website. Fifty references, prices from CHF 9 to CHF 80, identical promises. They all claim to be "complete," "premium," "scientifically formulated." How do you actually choose?

I have spent more than ten years formulating dietary supplements for Swiss, European and global brands. Seen from the inside, the multivitamin market is a minefield.

This article brings together what people who supplement should know first, before purchasing a dietary supplement.

The 4 criteria that actually determine the effectiveness of a multivitamin

The vast majority of multivitamins sold are inorganic molecules, sweeteners and preservatives (often harmful) in a pretty box. Here are the 4 technical criteria that separate a supplement that works from one that ends up in the waste bin of our metabolism.

1. The bioactive form of each vitamin

The bioactive form of each vitamin is a fundamental criterion, and the one that most brands carefully conceal. A vitamin always exists in several molecular forms: some are immediately recognised and used by the cell; others require a series of biochemical conversions whose yield varies considerably from one individual to another. Two distinct realities must not be confused here: truly synthetic forms, produced by chemical processes and often poorly recognisable by the body, and synthesis forms, molecularly identical to those present in living organisms and whose safety is established. The determining criterion remains bioactivity: the actual capacity of a molecule to enter into action in the cell, without an additional conversion step.

The examples that make the difference:

• Vitamin B9 or Folate: folic acid (pteroylmonoglutamate, E1518) must go through several enzymatic steps via the MTHFR enzyme to convert into 5-methyltetrahydrofolate (5-MTHF, or levomefolate), its bioactive form. However, 30 to 50% of the population carries a mutation of the MTHFR gene that drastically reduces this conversion. 5-MTHF is directly assimilated by all cells, without an intermediate step.
• Vitamin B12 or Cobalamin: cyanocobalamin, an inexpensive precursor with low bioavailability, contains a cyanide group that the liver must neutralise before any activation. Methylcobalamin, directly usable, supports the nervous system, cellular methylation and the reduction of homocysteine. Hydroxocobalamin, a natural form with a prolonged half-life, shows better retention in the body and easily converts into active forms; it is particularly indicated in cases of severe deficiency or when progressive release is sought.
• Vitamin B6 or Pyridoxine: pyridoxine HCl, although of natural origin, requires hepatic phosphorylation before being used by the body. Well absorbed, it acts as a reserve that progressively transforms into P-5-P, providing a delayed effect that complements the immediate action of the active form. Pyridoxal-5-phosphate (P-5-P) is the already-phosphorylated form, directly available to enzymes, without prior conversion.
• Selenium: sodium selenite, an inorganic form with limited absorption (around 25%), contrasts with L-selenomethionine, an organic form with bioavailability above 90%, which integrates directly into endogenous proteins.
• Magnesium: magnesium oxide shows a bioavailability of barely 4%. Bisglycinate and magnesium citrate exceed 40% absorption, with markedly superior digestive tolerance.
• Vitamin E: natural d-alpha-tocopherol is absorbed 2× better than the synthetic dl-alpha version.

How to verify? Read the ingredient label. If you see "magnesium oxide," the brand has prioritised cost over bioavailability. The presence of "cyanocobalamin" signals an inefficient precursor. "Pyridoxine HCl," on the other hand, is neither dangerous nor ineffective: it constitutes a useful residual form complementing P-5-P, provided the latter is present in sufficient proportion.

2. The actual dosage, not the RDA

The Recommended Daily Allowances (RDA, or NRV in Europe) are calibrated to avoid severe deficiency, not to reach optimal health. The RDA for vitamin D is 5 µg/day: enough to prevent rickets, insufficient to support immunity or mood. It is therefore preferable to focus attention on dosages in absolute weights.

Beware of products that display astronomical dosages in mg without specifying the form. A "magnesium 500 mg" in oxide form will bring less elemental magnesium into the cell than a "magnesium 200 mg" in bisglycinate form.

3. Formula synergy

An isolated vitamin rarely works as well as a vitamin in context. A few key synergies:

• Vitamin D requires magnesium for its conversion to the active form. Without magnesium, supplementing with D could paradoxically worsen a magnesium deficiency.
• Non-haem iron sees its absorption significantly improved by vitamin C; these two molecules must not, however, be found in the same dietary supplement, as their direct contact in aqueous solution can induce a mutual oxidation reaction that degrades both compounds before any cellular absorption.
• The B vitamins act in cascade and assimilation is improved when the entire B-vitamin complex is present.
• Zinc and copper must not be dosed together, as zinc will neutralise copper.

A good multivitamin is not a stack, it is an orchestra, a symphony.

4. Purity and origin

A dietary supplement is not regulated like a medication. This means the brand is responsible for its own quality. Three questions to ask:

• Where is it manufactured? Switzerland, the EU and certain Nordic countries impose strict quality controls. China and certain other regions allow much greater latitude on contaminants (heavy metals, pesticides, residual solvents).
• What excipients? Avoid for example titanium dioxide (E171, banned in France), artificial sweeteners such as aspartame or acesulfame K, superfluous colourings, etc.
• Heavy-metal presence in Omega 3: request a technical sheet or a report from an independent laboratory.

Powdered multivitamins vs capsules

A frequent question, a clear answer: powder allows more active material. A capsule contains on average 500 mg of powder. This mechanically limits the number and dosage of ingredients you can integrate. A 6 g powder serving contains the equivalent of 12 capsules in terms of nutritive matter. Of course, for Omega 3 and certain other liposoluble compounds, oil or capsules are indispensable.

Stay attentive, however, to taste and texture. A good powder formulation integrates natural aromas and a fine granulometry to avoid a sandy effect. If you tolerate the powder format, you gain access to optimised dosages and combinations.

Bioactive forms: what the label does not say

Is the form used the one the cell recognises immediately? In micronutrition we speak of bioactivity: the actual capacity of a nutrient to enter into action without a conversion step. The bioactive form thus presents a measurable functional superiority over the less elaborate version. This is not a marketing argument: it is a documented biochemical reality.

A rigorous formulation systematically favours bioactive forms where the clinical advantage is demonstrated. It does not, however, exclude certain synthesis forms whose safety is established and whose complementary role is favourably documented. This is more demanding to formulate, more expensive to produce, and what distinguishes a supplement that acts in the cell from a supplement that transits through the digestive tract.

My final test: 3 questions to ask a brand

Before buying, ask (by email if necessary):

1. What is the exact form of each nutrient in your supplement?
2. Can you share the scientific dossier of your formula?
3. Who formulated this product?

If you get 3 clear answers, you have probably found a product worth its price. If you get vagueness or no answer, move on.

Choosing a multivitamin is in reality about understanding what your body will actually receive once the intestinal barrier is crossed. Bioavailability, forms, synergies: all this matters more than the marketing.

I created base One — after sixteen years in the field of therapy and ten years of supplement formulation — so that a clean, uncompromising formulation, delicious to drink and manufactured in Switzerland, would exist.