L-5-Methyltetrahydrofolate (L-Methylfolate, free acid) vs. Quatrefolic (glucosamine salt of L-5-MTHF, brand)
Among 1,041 on-market folate (vitamin b9) products with an identifiable primary form, 29.8% use L-5-Methyltetrahydrofolate (L-Methylfolate, free acid) (310 products) and 23.2% use Quatrefolic (glucosamine salt of L-5-MTHF, brand) (241).
| L-5-Methyltetrahydrofolate (L-Methylfolate, free acid) | Quatrefolic (glucosamine salt of L-5-MTHF, brand) | |
|---|---|---|
| Quality tier | Tier 1 | Tier 1 |
| Folate (Vitamin B9) by weight | — | 56.2% |
| Share of market | 29.8% | 23.2% |
| On-market products | 310 | 241 |
| Median declared dose | 400 mcg DFE middle half: 333–667 | 340 mcg DFE middle half: 170–680 |
| Most common brands | Douglas Laboratories, SmartyPants, New Chapter | XYMOGEN, Pure Essence Ionic-Fizz, Ortho Molecular Products |
Doses are declared per serving in mcg DFE. “By weight” is the share of the ingredient that is the nutrient itself (e.g. elemental magnesium in a magnesium salt).
Why L-5-Methyltetrahydrofolate (L-Methylfolate, free acid) is tier 1
The natural, circulating, already-"active" form that bypasses the MTHFR conversion step entirely; raised serum folate more effectively than folic acid in an RCT, though that trial found no additional miscarriage-prevention benefit over folic acid regardless of MTHFR genotype -- avoid overselling the MTHFR-relevance angle.
Source: Hekmatdoost A et al. 2015, PLoS One 10(12):e0143569, PMID 26630680
Why Quatrefolic (glucosamine salt of L-5-MTHF, brand) is tier 1
Same active folate species as Metafolin/L-5-MTHF, using glucosamine instead of calcium as the salt-forming counterion for solubility. No head-to-head trial of Quatrefolic vs Metafolin vs generic L-5-MTHF was found -- treat any distinction between these three brands as uncertain.
Source: uncertain -- needs review for a brand-specific comparison