Comparison guide
Which folate should you take?
Folic acid is the form that prevented neural tube defects in trials; L-methylfolate and folinic acid are sold as smarter choices for people with MTHFR variants. That mechanism is plausible, but no trial shows better outcomes, and most MTHFR carriers do fine on ordinary folic acid.
The options, compared
| Option | Evidence | Best for | The honest note | |
|---|---|---|---|---|
| Folic Acid (Vitamin B9) | Strong evidence | Pregnancy and most people | Periconceptional folic acid cut neural tube defects by about 70% in a Cochrane review, and it is the cheapest form. Check B12 before high doses, since folate can mask a deficiency. | View |
| L-Methylfolate | Limited evidence | Supervised antidepressant add-on | At 15 mg/day it beat placebo as an add-on in two small manufacturer-sponsored trials, and it avoids unmetabolised folic acid, but it has never been shown clinically superior to folic acid. It is untested for preventing neural tube defects. | View |
| Folinic Acid | Moderate evidence | Autism, under a clinician | Small trials in autistic children with language impairment are positive at 2 mg/kg/day under supervision. The MTHFR reason most adults buy it has never been tested. | View |
Our verdict
Folic acid is the default, and in pregnancy it is the evidence-based choice at 400–800 mcg/day, starting at least one month before conception. L-methylfolate and folinic acid are acceptable alternatives with no proven advantage for most people, including most MTHFR carriers — you pay a premium for a mechanism. Whatever form you take, check B12 first if you are older or on metformin.