Calcium L-5-Methyltetrahydrofolate (Metafolin, brand) vs. Quatrefolic (glucosamine salt of L-5-MTHF, brand)
Among 1,041 on-market folate (vitamin b9) products with an identifiable primary form, 47.1% use Calcium L-5-Methyltetrahydrofolate (Metafolin, brand) (490 products) and 23.2% use Quatrefolic (glucosamine salt of L-5-MTHF, brand) (241).
| Calcium L-5-Methyltetrahydrofolate (Metafolin, brand) | Quatrefolic (glucosamine salt of L-5-MTHF, brand) | |
|---|---|---|
| Quality tier | Tier 1 | Tier 1 |
| Folate (Vitamin B9) by weight | 92.3% | 56.2% |
| Share of market | 47.1% | 23.2% |
| On-market products | 490 | 241 |
| Median declared dose | 667 mcg DFE middle half: 340–680 | 340 mcg DFE middle half: 170–680 |
| Most common brands | Metagenics, Pure Encapsulations, NaturesPlus | 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 Calcium L-5-Methyltetrahydrofolate (Metafolin, brand) is tier 1
Same active-form rationale as L-5-MTHF -- the calcium salt is simply the stabilized, tabletable version of the same active molecule (not separately tested head-to-head).
Source: Hekmatdoost A et al. 2015, PMID 26630680 (parent vitamer's tier rationale)
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