Vitamin
Vitamin B9
Also known as: Folate, L-Methylfolate
An essential vitamin required for DNA synthesis, brain development, and neurotransmitter function.
KÖGN Health grades Vitamin B9 as A+ (Strong evidence) and rates it 4.5 out of 5.
Last reviewed · June 2026
Primary effects
- Mood support
- Cognitive clarity
- Brain health
How it works
Supports methylation and neurotransmitter production, influencing mood and cognitive function.
Overview
Vitamin B9 in its active form (L-methylfolate) is critical for neurological function and methylation processes. It plays a key role in neurotransmitter synthesis and has been strongly linked to mood regulation. Deficiency is associated with cognitive decline and mood disorders, making it essential for long-term brain health and stability.
The evidence
Folate (vitamin B9) works alongside B12 and B6 to lower homocysteine, a marker linked to cognitive decline. In the VITACOG trial, high-dose folic acid with B12 and B6 slowed brain atrophy and helped cognition in older adults with mild cognitive impairment — but the benefit concentrated in those with elevated homocysteine. As a general enhancer in well-nourished people, the evidence is weak.
How to dose it
The reference intake is 200–400 µg/day; the VITACOG protocol used 800 µg/day of folic acid. Higher intakes are usually reserved for correcting raised homocysteine under guidance.
When to take it
Chronic — effects accrue over months of consistent use.
Safety & side effects
Well tolerated. The main caution is that high folic acid can mask the blood signs of B12 deficiency while nerve damage continues, so B12 status should be checked alongside it.
Who should avoid it
Do not take high-dose folic acid without also ensuring adequate B12, particularly if you are older or vegan. Discuss with a clinician if you take methotrexate or anti-epileptic medication, which interact with folate.
References
Related ingredients
Graded entries that target the same cognitive goals.
Categories
Draft — the dose, safety and evidence notes on this entry were prepared from the published literature and are pending editorial and clinical review.
Educational information, not medical advice. The evidence grade is KÖGN’s editorial assessment of published research, not a health claim. Speak to a qualified clinician before changing what you take.