Health Reference Library

Can you take B12 and folate together?

This entry is part of the Nutri Tailor Health Reference Library — cited research on supplements, nutrients and adjacent areas of health.

Summary

Yes. B12 and folate are partners in the same cycle, the one that recycles homocysteine and makes the methyl groups cells use, and each is stuck without the other. That is why NICE guidance tests both when either is suspected, and why the two are often supplemented together. There is one rule that matters: do not take folate on its own for tiredness or a low blood count without a B12 test first, because folate can correct the anaemia of B12 deficiency while the nerve damage from low B12 continues unseen. Taken together at ordinary doses they do not interfere with each other, and a combined product is a sensible way to cover both.

How it works

Folate carries a methyl group; B12 hands it to homocysteine to make methionine, which the body uses for DNA, nerve insulation and hundreds of methylation reactions. When B12 is short, folate gets trapped in its methyl form and cannot be reused, which looks like folate deficiency and causes the same large cell anaemia. Give folate alone and the blood count improves, but the B12 dependent repair of nerve insulation does not, which is the masking problem the guideline warns about. The active forms, methylfolate and methylcobalamin, enter the cycle directly; folic acid and cyanocobalamin are converted first.

Effective dose

Reference intakes: B12 1.5 micrograms a day, folate 200 micrograms a day, with 400 micrograms of folic acid a day advised before and during early pregnancy. Supplements pairing 400 to 1000 micrograms of folate with 1000 micrograms of B12 are common and safe for adults. The upper limit for folic acid from supplements is 1000 micrograms a day; methylfolate is not subject to the same masking concern in the same way but the B12 rule still applies. B12 has no upper limit.

Timing

Any time, with or without food, together. If you are correcting a low result, retest both after eight to twelve weeks. Homocysteine is the marker that tells you the cycle is running; it falls within weeks once both are adequate.

Safety profile

The safety issue is diagnostic, not toxic. A low B12 without an obvious dietary cause needs a GP to look for pernicious anaemia or absorption problems before supplements are chosen. Folic acid above 1000 micrograms a day long term is not advised. People on plant based diets need a B12 source for life.

Interactions

Folate and B12 depend on each other as above; vitamin B6 is the third partner in homocysteine handling. Folate absorption is reduced by heavy alcohol use. High dose vitamin C taken at the same time can affect B12 in some tablets, so a couple of hours apart is tidy but not essential.

Guideline positions

NICE NG239 (2024): vitamin B12 deficiency in over 16s. NICE Clinical Knowledge Summary: anaemia, B12 and folate deficiency, which recommends testing both. NHS: folic acid 400 micrograms before and during early pregnancy. EFSA scientific opinion on the upper intake level for folate (2023). Vitamin B12 deficiency, review (2013).

Practical framework

Test first if you have symptoms; supplement the pair if your diet is the reason. Nutri Tailor stocks [B12 and folate capsules](/products/b12-and-folate), 1000 micrograms of each in their active forms, methylcobalamin and calcium L-methylfolate, one a day; and the singles, [methylfolate](/products/methyltetrahydrofolate) at 1000 micrograms and methylcobalamin capsules at 1000 micrograms, for people who need only one, all made in the UK. To read your own result against the UK ranges, use the free blood test result interpreter. This is a summary of published research, not personal health advice. Talk to your GP or a registered nutritional therapist before changing what you take, especially if you are pregnant, have a diagnosed condition or are under ongoing care.

Common misconceptions

That folate and B12 compete: they cooperate. That a normal blood count rules out B12 deficiency: folate can normalise it while B12 stays low. That methylfolate is only for people with an MTHFR variant: it suits anyone, and the variant question is smaller than the marketing suggests. That B12 alone raises folate: it frees trapped folate but does not add any.

Sources

  1. UK NICE 2024. Vitamin B12 deficiency in over 16s: diagnosis and management. National Institute for Health and Care Excellence (NICE).
  2. NICE Clinical Knowledge Summary (CKS, UK government). Anaemia - B12 and folate deficiency. NICE Clinical Knowledge Summaries (CKS).
  3. EFSA Panel on Nutrition, Novel Foods and Food Allergens (NDA) 2023. Scientific opinion on the tolerable upper intake level for folate. EFSA Journal. DOI: 10.2903/j.efsa.2023.8353
  4. Stabler SP 2013. Vitamin B12 deficiency. New England Journal of Medicine. PMID: 23301732 · DOI: 10.1056/nejmcp1113996
  5. Food Standards Agency (FSA, UK government). Folic acid. Food Standards Agency (FSA, UK government).

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