I've read only one study that suggests Lithium may play a role in b12 transport. I wish it was more deeply researched so I could understand the mechanisms by which it helps. Does anyone know of any other papers I could read? However, I'm satisfied that it does play a role based on personal experience (felt an enabling effect from acute methylcobalamin administration, the effect had diminishing returns until I supplemented lithium upon which it returned to full effect). It seems to be a similar situation with nickel. There are some studies (1, 2) suggesting a collaborative role for nickel in folate and/or b12 metabolism. Nickel is a bugger to supplement though. I've been hoping to get some by taking chocamine (a chocolate extract; chocolate is allegedly high in nickel, although I've heard that that's more due to the manufacturing process than a naturally high content?). I'm wondering again if anyone has any insight on nickel's role in this picture, and/or whether a supplement exists for it.