Low folate

Written to our editorial standards · reviewed against published research· Updated 2 Jun 2026

Low folate, like low B12, causes fatigue and is involved in low mood and raised homocysteine; it is corrected with methylfolate, ideally checked alongside B12.

Folate works as a pair with B12 in making red blood cells and in the methylation pathway that keeps homocysteine, a cardiovascular and cognitive risk marker, in range. A shortfall causes a large-cell anaemia and tiredness, and it is especially important before and during pregnancy for neural-tube development.

Common causes

  • Low intake of leafy greens, legumes, and fortified foods
  • Pregnancy (higher needs)
  • Heavy alcohol use
  • Certain medications
  • Malabsorption

Associated symptoms

  • Fatigue
  • Low mood
  • Mouth ulcers or a sore tongue
  • Poor concentration

Nutrients that can help

Methylfolate
See the guide →
Methyl-B12
See the guide →
What to do

Take methylfolate, and check B12 at the same time since the two are linked and B12 should not be missed. If you could become pregnant, adequate folate is a priority.

When to see a doctor

Confirm the cause with a doctor, and always pair folate with B12 testing so a B12 deficiency is not masked.

Full marker
Folate: ranges, what it measures & both directions
Read the Folate guide →

Common questions

What does low folate mean?
Low folate, like low B12, causes fatigue and is involved in low mood and raised homocysteine; it is corrected with methylfolate, ideally checked alongside B12. Folate works as a pair with B12 in making red blood cells and in the methylation pathway that keeps homocysteine, a cardiovascular and cognitive risk marker, in range. A shortfall causes a large-cell anaemia and tiredness, and it is especially important before and during pregnancy for neural-tube development.
What causes low folate?
Low intake of leafy greens, legumes, and fortified foods; Pregnancy (higher needs); Heavy alcohol use; Certain medications; Malabsorption.
How do I raise my folate?
Take methylfolate, and check B12 at the same time since the two are linked and B12 should not be missed. If you could become pregnant, adequate folate is a priority.
When should I see a doctor?
Confirm the cause with a doctor, and always pair folate with B12 testing so a B12 deficiency is not masked.

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Educational use only, not medical advice or diagnosis. Reference ranges vary by lab, age, sex, and medication, and a single result is read in context. Always review your results with a qualified clinician.