Pernicious Anaemia Society
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Folate upper limit

Is there an acceptable upper limit for folate?

My most recent result just says >24 ng/ml on the letter but a previous test result has the range at 3.3/99999.0 ng/ml and another at 4.6-18.7ug/l

All very confusing

I'm debating whether to stop my multivitamin even though it only has 200mcg or folic acid.

I don't want "too much" of anything especially with there being confusion out there about excess folic acid maybe (loosely) increasing the risk of further damage.

2 Replies

not quite the answer to your question but this is a link to EFSA recommendations for upper limits for supplementation of various minerals and vitamins - goes into quite a lot of detail for each on reasons for recommendations (assessment of risks etc)

The main risk from high folate levels is the risk of masking macrocytosis caused by B12 deficiency - which will delay diagnosis if macrocytosis is being used as a defining marker.

There appear to have been a few (1-2) reported cases where treatment with large doses (5mg) of folic acid appears to have brought on SACD in humans which is why it is recommended that treatment with B12 starts before treatment with folic acid but only by a short period of time - eg a day.

The main damage of over-supplementing folic acid is the cost of supplementation that you don't need that you will, quite literally, end up flushing away.


Hi Steap...I agree with Gambit.

In terms of damage from folic acid...your B12 levels are now high enough for is to not be a problem (only a potential issue if B12 levels are deficenct or low in the range - and yours aren't - at least not now 😄).

You could look at the Mayo clinic website (search for folic acid) for details about potential side effects (rare but do exist if over supplementation takes place - insomnia is one).


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