5-MTHF
Research Reliability -
The bioactive form of folate that supports methylation, mood, prenatal health, and cardiovascular function.
Appetite
Mood
Sleep
5-MTHF
Description
5-MTHF (methyltetrahydrofolate) is the active, ready-to-use form of folate that bypasses the MTHFR enzyme conversion step required by synthetic folic acid. It is essential for single-carbon metabolism, DNA synthesis, and neurotransmitter production. Individuals with MTHFR polymorphisms cannot efficiently convert folic acid and should use this form. It is critical during pregnancy for neural tube development, and supports homocysteine regulation, mood stability, and cardiovascular health across all life stages.
Effects
First 2 weeks
subtle
Weeks 2–4
for those who do not process folic acid well, mood and energy may lift
Ongoing
methylation and homocysteine support
How It Feels
Most people feel little. Those with an MTHFR variant sometimes notice a real mood or energy shift, since this is the already-active form of folate. A small subset feels wired or irritable, which signals the dose is too high.
Evidence
Evidence Strength
Evidence Strength
Caveats
Evidence Strength
Usage
Commonly Referenced Starting Amount
400mcg
Commonly Referenced Amount
1000–5000mcg
Referenced Upper Limit
15000mcg
Onset
2–4 weeks
Biomarkers to Track
Subjective
(Daily)
Mood and emotional resilience
Energy and mental clarity (1–10)
Sleep quality score
Objective
(Quarterly)
Homocysteine level
RBC folate level
MTHFR genotype (once, baseline)
Risks
Generally safe as the active folate form. A subset feels wired or irritable, a sign of overmethylation.
Who Should Skip
People on certain chemotherapy or seizure medications should check first.
Common Mistakes
Starting at a high dose rather than easing in, and ignoring irritability as a cue to lower it.
Disclaimer
This information is for educational purposes only and is not medical advice. It is not intended to diagnose, treat, cure, or prevent any disease. Consult a qualified healthcare provider before starting any new supplement, especially if you are pregnant, nursing, taking medication, or managing a health condition.
Citations
Shaw K et al. (2002). Cochrane Database of Systematic Reviews. Meta-analysis (5-HTP for depression). PMID: 11869656.