Folic acid or folate: where the difference lies

The short answer: "folate" is the collective term for the forms of the vitamin that occur naturally in foods, "folic acid" the synthetic form in supplements and fortified products. It is the same vitamin — but the amounts cannot be compared directly: 400 µg from a tablet counts for more, nutritionally, than 400 µg from a salad. That is exactly why there is a unit of calculation of its own, the folate equivalent.

This is the point at which the label and the food composition table part company. The pack carries a figure in µg, the nutrition table for spinach likewise carries a figure in µg, and the two mean different things. Adding them together gives the wrong answer — as a rule, one that is too low.

Three names for one vitamin

Folate is, in the definition used by the German Nutrition Society (DGE), the umbrella term for the compounds with vitamin activity that occur naturally in foods. There they are present mostly as polyglutamates — that is, with a chain of attached glutamic acid residues that first has to be cleaved off in the gut before the vitamin is absorbed. On top of that, folates are water-soluble and sensitive to heat, light and long soaking. The two together explain why less of the folate on the plate arrives than the table suggests.

Folic acid is the synthetically produced form, chemically pteroylmonoglutamic acid (also pteroylmonoglutamate). It practically does not occur in nature, is more stable and carries only a single glutamic acid residue — which is why it is absorbed far more completely. In return it is not yet the active form: folic acid has to be converted in the body, in several steps, into 5-methyltetrahydrofolate, as the German Federal Institute for Risk Assessment (BfR) describes in its opinion 009/2024.

5-MTHF (5-methyltetrahydrofolate) is precisely that active form — the form that circulates in the blood. In supplements it appears on the ingredients list as calcium-L-methylfolate or as 5-MTHF glucosamine and is often advertised as "the natural folate". Chemically it too is an industrial product; its advantage lies elsewhere, on which more below.

Why the numbers are not comparable

To bring the various forms onto a common denominator, the calculation is done in folate equivalents. At first glance the conversion looks like bookkeeping, but it decides whether a sum works out.

Form of intake	Equals 1 µg folate equivalent
Food folate	1 µg
Folic acid, taken on an empty stomach	0.5 µg
Folic acid, taken together with food	0.6 µg
5-MTHF from supplements, from 400 µg/day upwards	0.5 µg
5-MTHF from fortified foods and from supplements below 400 µg/day	0.6 µg

Source: BfR opinion 009/2024, following the conversion factors derived by the EFSA.

Calculated the other way round, the formula reads: folate equivalents = food folate + 1.7 × folic acid + 1.7 × 5-MTHF — or + 2 × 5-MTHF where the intake from the supplement is 400 µg per day or more.

In practice that means: a tablet with 400 µg folic acid contributes around 680 µg folate equivalents. A portion of spinach with 400 µg folate contributes 400. The figure on the tin and the figure in the nutrition table are therefore in different units, even though both are called "µg".

What is authorised in the EU as a folate source

Not every folate compound may go into a food supplement. Under Directive 2002/46/EC, three sources are currently authorised:

• Pteroylmonoglutamic acid — the classic folic acid
• Calcium-L-methylfolate
• 5-MTHF glucosamine, added by Regulation (EU) 2015/414 of 12 March 2015

A fourth source is in the queue: 5-MTHF sodium salt was assessed by the EFSA in 2023 as safe for health; authorisation by the EU Commission was, according to the BfR, still pending in January 2024. Whatever is offered on a label as "folate" or "active folate" is therefore one of these compounds — the marketing term says nothing about which.

5-MTHF or folic acid: what the data support

Here it pays to read closely, because the advertising message and the state of the evidence overlap only in part.

The BfR sums up the position like this: the bioavailability of calcium-L-methylfolate is comparable with that of pteroylmonoglutamate. The difference lies in the metabolic route — after absorption, calcium-L-methylfolate feeds straight into folate metabolism, whereas folic acid first has to be converted. Calcium-L-methylfolate also leads to higher folate concentrations in the red blood cells (Lamers et al. 2006; Pietrzik et al. 2001).

The German consumer association (Verbraucherzentrale) puts it more pointedly: 5-MTHF and calcium methylfolate are, it says, "more quickly, but not necessarily better bioavailable". An advantage is discussed above all for carriers of a particular gene variant, the MTHFR polymorphism, in which the conversion capacity is reduced by up to 25 percent. At the same time the Verbraucherzentrale points out that the effects of 5-MTHF on folate status in the blood during pregnancy have not yet been sufficiently researched — in precisely the phase of life for which the clearest recommendation exists.

So for anyone standing in front of the shelf: what is decisive is the amount of folate equivalents, not the name of the compound. The DGE too permits both and, for those trying to conceive, speaks of "400 µg of synthetic folic acid or equivalent doses of other folates". When those 400 µg should begin and why the moment lies before the test is set out in Folic acid in pregnancy: 400 µg, from when.

What is on the label

On the pack the difference barely shows up — and there is a legal reason for that. Nutrition labelling knows only one name: Annex XIII of Regulation (EU) No 1169/2011 lists "folic acid (µg)" with a reference value of 200 µg per day. A supplement containing calcium-L-methylfolate likewise calculates its percentage against those 200 µg. Which compound is actually inside is therefore not in the nutrition table but in the ingredients list.

Three pieces of information are decisive when comparing two packs: the amount per daily dose rather than per 100 g, the percentage of the nutrient reference value and the compound used. Folic acid 1000 µg, for instance, gives the amount as folic acid — anyone wanting to turn that into folate equivalents multiplies by 1.7. Anyone looking for a different strength will find it in the folic acid category.

The reference values side by side

Reference value	Amount
Nutrient reference value (NRV) on the label	200 µg folic acid
D-A-CH reference value, adolescents from 13 years and adults	300 µg folate equivalents per day
D-A-CH reference value, pregnant women	550 µg folate equivalents per day
D-A-CH reference value, breastfeeding women	450 µg folate equivalents per day
EFSA reference value, from 15 years	330 µg folate equivalents per day
Additionally when trying to conceive (D-A-CH)	400 µg folic acid or an equivalent amount of 5-MTHF
Upper limit (UL), adults including pregnant and breastfeeding women	1,000 µg per day
Upper limit (UL), 15 to 19 years	800 µg per day

The upper limit deserves a note, because it is often quoted wrongly: it applies only to synthetic intake — to folic acid and the authorised 5-MTHF salts taken together, not to folate from foods. A high intake of naturally occurring folates is, on the DGE's current understanding, not harmful. Nor is the endpoint from which the 1,000 µg were derived a risk of poisoning; it is the possibility that plentiful folic acid masks a vitamin B12 deficiency in the blood count. The EFSA confirmed this assessment in 2023 and expressly found no established link with bowel or prostate cancer or with cognitive impairment. Why the B12 question always runs alongside folic acid is set out in Vitamin B12 and folic acid: why the gap gets masked — the matching strength for it is Vitamin B12 1000 µg.

What may be said about folate

The authorised claims in Regulation (EU) No 432/2012 use the word folate throughout — regardless of which compound is in the product. Word for word they read:

Folate contributes to normal blood formation.

Folate contributes to normal amino acid synthesis.

Folate contributes to normal psychological function.

Folate contributes to the reduction of tiredness and fatigue.

Folate contributes to maternal tissue growth during pregnancy.

So anyone who reads "Folate contributes to …" on a pack and concludes from it that the natural form is inside is reading in information that is not there. The wording is laid down in law and is the same for all authorised sources. Food supplements are not a substitute for a balanced and varied diet and a healthy lifestyle.

Frequently asked questions

Is folate from foods better than folic acid from a tablet? Folic acid is the better absorbed of the two — it is more stable and needs no cleavage in the gut. That is the reason for the factor 1.7. "Better" in the sense of overall supply is nonetheless a folate-rich diet, because it delivers everything else along the way; the 400 µg for those trying to conceive is named by the DGE expressly as an addition to it.

Do I need 5-MTHF if I have the MTHFR polymorphism? With this gene variant the conversion capacity is, according to the Verbraucherzentrale, reduced by up to 25 percent — reduced, not abolished. Sound evidence that 5-MTHF leads to better results in this situation is so far lacking; for pregnancy the state of the data is expressly described as insufficient.

Why does my supplement say "pteroylmonoglutamic acid"? That is the chemical name of folic acid, not an additive and not a different substance. It appears in the ingredients list because that is where the compound used has to be stated; in the nutrition table the same amount then appears as "folic acid".

Can I simply add folate from food and folic acid from a supplement together? Not directly. Convert first: food folate counts once, folic acid with the factor 1.7. Anyone who wants to keep an eye on the upper limit calculates the other way round — the 1,000 µg per day refer to the pure amount of folic acid or 5-MTHF from supplements and fortified foods, without folate-equivalent conversion and without the folate from food.