> Excess B12 is really bad. Neuropathy.
Do you have any source for this? I can find some "it-might-be-bad" studies through a quick googling, but in general the idea seem to be that excess B12 is thought to be unproblematic ("it's just peed out").
Do you have any source for this? I can find some "it-might-be-bad" studies through a quick googling, but in general the idea seem to be that excess B12 is thought to be unproblematic ("it's just peed out").
I accidentally poisoned myself with B6 from Magnesium tablets over the course of a year: https://davids.town/vitamin-b6-overdose (my levels were 38x the healthy range).
tl;dr: Always check your Magnesium for what else the tablet includes. If it contains Pyridoxine hydrochloride (i.e. Vitamin B6) or another Pyridoxine compound, find one that doesn't. Since then, Swisse is the only brand I've found that consistently sells "pure" Magnesium tablets here in Australia.
I take 50mg a day in a bio-available form pyridoxal-5-phosphate. Consider this form instead.
I'm taking it because there is some genetic evidence that I would benefit from doing so. No neuropathies thus far but it's only been about a month and a half.
Blood tests since then have shown that my B6 levels are fine with my usual diet, I don't take multivitamins or supplements anymore.
I don't know much about B6 beyond my own experiences with it, so all I can say is make sure you've discussed it with your GP, and be aware of the coasting effect if you do happen to develop any neuropathic symptoms: https://en.wikipedia.org/wiki/Megavitamin-B6_syndrome
Genetic data is useful to know really, especially for people with MTHFR mutations as many pathways get affected.
UK/EU upper safety limits are at 10-12mg per day. US UL of 200mg is way past due for an overhaul.
I personally got sick from a B complex with 40mg pyridoxine after just 4 months. Developed dysautonomia (not a canonical example, but still a kind of neuropathy - damage to autonomic nervous system). Had random tachycardia and high blood pressure flares from various triggers every week, took a while to figure out what was really causing it. Your typical non-neurologist GP wouldn't know anything because "it's water soluble" and the textbooks say neuropathy develops at 200mg+. All symptoms mostly resolved after a month once I threw away everything with pyridoxine. Wouldn't touch it again, always on a lookout for B6 in my multis and supplements now. P5P form is thought to be safer, but also got people sick - look around on facebook B6 groups for more anecdata.
No problem with B12 as far as I know. It's not a neurotoxin unlike B6.