Thorne 5-MTHF 1 mg (Methylfolate) Review
#6 of 9 · Best Therapeutic Dose✓ Label verified · Supplement Facts read Sep 7, 2026Real retailer photo, cut out. Label unedited.
Consider it. Therapeutic active folate, not a routine prenatal. High-quality 1 mg L-5-MTHF from a trusted brand.
$22 approx~$0.37 / capsule
Why It Scores 6.6 — And The Label Line Behind Each Number
Form & Evidence Base
30% of scoreMethylfolate lacks NTD-prevention trials, and a therapeutic dose does not change that — no evidence 1 mg prevents more defects than 400 mcg folic acid. The form itself is bioidentical L-5-MTHF, conversion-free, from a brand with rigorous quality control.
- Form
- L-5-MTHF capsule
Dose vs Clinical Target
25% of score1 mg is above the 400–800 mcg prenatal window — appropriate for therapeutic use but excessive for routine prevention.
- Dose
- 1 mg (1,000 mcg) L-5-MTHF
Third-Party Testing & Purity
20% of scoreThorne is known for rigorous third-party testing and athletic-grade quality control.
- Testing / Certification
- Third-party tested, Gluten Free, Dairy/Soy Free
Tolerability & Safety
15% of scoreFree of dairy, soy and gluten, but high active-folate intakes are still an area of ongoing study — the extra milligram is cost without a proven upside for most.
Value
10% of scoreAbout $22 for 60 capsules — a premium price for a dose most buyers don't need.
- Count
- 60 capsules
- Cost per dose
- ~$0.37 per capsule
Label verified. Every figure read from the Supplement Facts photo, Sep 7, 2026.
Marketing Claims Vs. Reality
1 mg methylfolate is better for MTHFR carriers
Active folate bypasses conversion and higher doses can lower homocysteine, but there is no evidence a 1 mg dose improves pregnancy outcomes over standard 400–800 mcg for typical carriers (PMID 19917061, PMID 23482308).
Therapeutic-dose folate prevents NTDs better
No trial shows 1 mg methylfolate prevents more neural-tube defects than the standard folic acid dose; folic acid holds the prevention evidence.
What Our Test Actually Found
Great brand, wrong tool for routine prevention
Thorne's quality is real, but 1 mg of active folate is a therapeutic dose aimed at homocysteine or methylation issues — not the profile a healthy woman needs for basic NTD prevention.
More is not better here
Above the 400–800 mcg target there is no added NTD-prevention benefit, and high active-folate intakes are still an area of ongoing study — so the extra milligram is cost without a proven upside for most.
Full analysis: all pros & cons (7), buy if / skip if
- Top-tier clinician brand with rigorous third-party testing
- Bioidentical L-5-MTHF, no conversion required
- Appropriate for elevated homocysteine or clinician-directed use
- Free of dairy, soy and gluten
- Reliable potency and purity
- 1 mg dose exceeds the 400–800 mcg prenatal target for most women
- Premium price for a dose and form most buyers don't need
- Top-tier clinician brand with rigorous third-party testing
- Bioidentical L-5-MTHF, no conversion required
- Appropriate for elevated homocysteine or clinician-directed use
- 1 mg dose exceeds the 400–800 mcg prenatal target for most women
- Premium price for a dose and form most buyers don't need
High-quality 1 mg L-5-MTHF from a trusted brand. Right for elevated homocysteine or clinician-directed higher intake — but more than most women need and pricier than the proven folic acid options.
Thorne is a gold-standard clinician brand, and this is its therapeutic-dose methylfolate: 1 mg (1,000 mcg) of L-5-MTHF, third-party tested. For someone with elevated homocysteine, a documented MTHFR variant, or a clinician's instruction to take a higher active-folate dose, it is a well-made, trustworthy choice. But read the dose honestly — 1 mg is well above the 400–800 mcg prenatal target, and for the general population that extra is neither needed nor proven to help. It ranks in the lower half because it pairs a premium price with a dose most women simply do not require, in a form without NTD-prevention evidence.
For a therapeutic need, not the shelf default
Buy this if a clinician has directed you to a higher active-folate dose, or you are managing elevated homocysteine. It is superbly made. But for routine preconception folate it is overkill in a form without NTD-prevention data, which is why it lands mid-pack despite the brand's excellent reputation.
If This Doesn’t Fit — Try These
05Pure Encapsulations 400
If you're set on methylfolate and prioritize purity, this is the cleanest option here — hypoallergenic, tested, and filler-free.
01Nature Made 400 mcg
This is the default folate for nearly every woman: the proven form, the proven dose, and the one product here carrying USP verification.
Quick Answers
Is 1 mg of methylfolate safe in pregnancy?
It is within commonly used therapeutic ranges, but it exceeds the routine prenatal target. Use a 1 mg dose only if a clinician recommends it for a specific reason such as elevated homocysteine.
Why does a premium brand rank this low?
Brand quality is high, but our method weights dose-appropriateness and proven outcomes. A therapeutic 1 mg dose in an unproven-for-NTD form is not the right routine prenatal choice for most women.
Sources & Further Reading
2 peer-reviewed sources, each linked to PubMed
- [1] Prinz-Langenohl R, Brämswig S, Tobolski O, et al. [6S]-5-methyltetrahydrofolate increases plasma folate more effectively than folic acid in women with the 677C→T MTHFR polymorphism. Br J Pharmacol. 2009;158(8):2014-21. PMID 19917061 — [6S]-5-methyltetrahydrofolate increases plasma folate more effectively than folic acid in women with the 677C→T MTHFR polymorphism. 5-MTHF raised plasma folate as effectively as folic acid, including in 677TT women, at standard doses.
- [2] Obeid R, Holzgreve W, Pietrzik K. Is 5-methyltetrahydrofolate an alternative to folic acid for the prevention of neural tube defects? J Perinat Med. 2013;41(5):469-83. PMID 23482308 — Is 5-methyltetrahydrofolate an alternative to folic acid for the prevention of neural tube defects?. Folic acid retains NTD-prevention trial evidence; methylfolate remains an unproven alternative.
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