Somewhere between TTC forums and wellness influencers, folic acid developed a reputation problem. The claim goes: it's synthetic, your body can't process it properly, and methylfolate is the smarter choice. So should you ditch the standard supplement your GP recommended?
Here's what the evidence actually says.
The difference is one conversion step
Folate is vitamin B9 in its natural form, found in food: leafy greens, lentils, oranges. Folic acid is the synthetic supplement version. Both need converting by your body into the active form it can actually use. Methylfolate (5-MTHF) is already that active form. It skips the conversion entirely. That's the whole basis of the debate.
Can't you just eat more folate instead?
In short: no. Dietary folate counts, but absorption from food is less reliable than from supplements, and the evidence base for neural tube defeats (NTDs) prevention was built on supplementation specifically. Eating plenty of leafy greens is a good idea, but it is not a substitute for a daily supplement when you are trying to conceive.
Why the NHS still recommends folic acid
Because the clinical evidence was built on folic acid specifically. The landmark MRC trial in 1991 (1) showed a 72% reduction in recurrent neural tube defects with folic acid supplementation. No large trial has tested methylfolate head-to-head for NTD prevention. Regulators recommend what has actually been tested.
The MTHFR question
MTHFR is an enzyme your body uses to convert folic acid. A common genetic variant, C677T, reduces how efficiently it works. People who inherit two copies may have roughly 30% of normal enzyme activity. For them, methylfolate makes practical sense: no conversion needed.
A 2026 randomised trial (2) found that women taking a methylfolate prenatal had significantly less unprocessed folic acid in their blood compared to those on standard folic acid (7% vs 31%), at equivalent total folate levels. The clinical significance is still under investigation, and the trial ran in the second and third trimesters rather than the earlier window where NTD protection is most critical.
There is no evidence of harm in choosing methylfolate. There is also no official recommendation to switch.
The bottom line
For most women trying to conceive: start folic acid (400mcg daily) now. The form matters less than starting in time. If you missed last week's post on exactly why the timing is everything, it's worth a read. Whether you choose folic acid or methylfolate, the priority is having adequate levels before conception, not at the point you get a positive test.
If you know you carry the MTHFR variant, or you've had recurrent pregnancy loss, speak to your GP or midwife before choosing a supplement. It's a reasonable question and increasingly one practitioners are asked.
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PregSafe is not a replacement for medical advice. Always consult your healthcare provider for personalised guidance.
Sources
(1) MRC Vitamin Study Research Group. Prevention of neural tube defects: results of the Medical Research Council Vitamin Study. The Lancet. 1991; 338(8760):131-137.
(2) Draicchio F, et al. Using 6S-5-methyltetrahydrofolate instead of folic acid in prenatal multivitamin reduces unmetabolized folic acid concentrations in the mother-fetus dyad: a randomized controlled trial. Frontiers in Nutrition. 2026. doi:10.3389/fnut.2026.1679067.
