Calcium L-5-Methyltetrahydrofolate (Metafolin, brand) vs. L-5-Methyltetrahydrofolate (L-Methylfolate, free acid)
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 29.8% use L-5-Methyltetrahydrofolate (L-Methylfolate, free acid) (310).
| Calcium L-5-Methyltetrahydrofolate (Metafolin, brand) | L-5-Methyltetrahydrofolate (L-Methylfolate, free acid) | |
|---|---|---|
| Quality tier | Tier 1 | Tier 1 |
| Folate (Vitamin B9) by weight | 92.3% | — |
| Share of market | 47.1% | 29.8% |
| On-market products | 490 | 310 |
| Median declared dose | 667 mcg DFE middle half: 340–680 | 400 mcg DFE middle half: 333–667 |
| Most common brands | Metagenics, Pure Encapsulations, NaturesPlus | Douglas Laboratories, SmartyPants, New Chapter |
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 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