ARI Publication 40 – 2013 Version
Forms of vitamin B6 There are six different forms of vitamin B6, including three unphosphated forms and their corresponding phosphated forms. All forms can be converted to one another, and should result in increases in the active forms {PLP and (for a few reactions) PMP). The six forms of vitamin B6 are: Pyridoxine (PN) & Pyridoxine 5-Phosphate (PNP) Pyridoxal {PL) & Pyridoxal 5-Phosphate {PLP) Pyridoxamine (PM) and Pyridoxamine 5-Phosphate (PMP) ARI survey data reports a slightly higher rate of adverse effects for PLP (11%) than for other forms of B6 (8%, or 4% if given with Mg). Analysis of their survey data suggests that some children do better on unphosphated forms (pyridoxine HCL), and some do better on the phosphated forms (PLP). Both forms should be well absorbed and have similar effects. So, we suggest first starting with pyridoxine HCL; if it is not effective, consider switching to PLP. All research studies to date have only investigated high-dose pyridoxine HCL for autism, and none have involved high-dose PLP .ARI Survey of Parent Ratings of Treatment Efficacy:
| %Worse | % No Change | % Better | Number of Reports | |
| Magnesium | 6% | 65% | 29% | 301 |
| Vitamin B6 (pyridoxine HCI) | 8% | 63% | 30% | 620 |
| Vitamin B6 with Magnesium | 4% | 46% | 49% | 7256 |
| PSP (Vit. B6) | 11% | 40% | 48% | 920 |
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