Why is there such a range of doses in B12 supplements? Why do they often provide tens of thousands of percent of the RDA? Is this safe? Why is it so hard to find more conservatively dosed supplements? How much…

There is no reliable naturally-occurring source of B12 on a plant-based diet and it is well-established that those not eating animal products must supplement this vitamin. But how much should you supplement? Why do supplements tend to have very high…