The form of vitamin B6 does indeed matter, for the following reason.
The most common vitamin B6 supplements use the synthetic pyridoxine instead of the natural pyridoxal-5'-phosphate, because the synthetic version is more shelf-stable than the natural form.
A small portion of the synthetic pyridoxine may be converted into the natural pyridoxal-5'-phosphate in the body, but a significant portion remains as the synthetic pyridoxine. As it turns out, the unconverted pyridoxine can block the action of the converted pyridoxal-5'-phosphate. If you take excessive doses, then the small converted portion will be overwhelmed by the large unconverted portion, and you may end up with a paradoxical B6 deficiency.
Unfortunately, there have been people here on Phoenix Rising who developed peripheral neuropathy from excessive doses of pyridoxine. Fortunately, the peripheral neuropathy appears to be mostly reversible by supplementation with the natural pyridoxal-5'-phosphate.
This phenomenon has been studied and is discussed in this scientific publication:
Supplementation with high concentrations of pyridoxine leads to decreased vitamin B6 function (Vrolijk et al., 2017)
https://forums.phoenixrising.me/thr...leads-to-decreased-vitamin-b6-function.53293/
I can't tell you what's best for you, but I can share what works for me:
- I take 400mcg methylfolate per day, which is roughly the U.S. Recommended Daily Allowance (RDA).
- I also take 250mcg hydroxo-B12 per week, which is roughly 15x the U.S. RDA. (This is still the lowest dose I could find.)