Chris Kresser: No, but I would typically like to see what they’re serum B12 is, what their methylmalonic acid is in the urine, and what their homocysteine is, and then I’d like to track those over time. If you have the training and understanding, it’s also interesting to look at their genetics, which can give you some insight into which form of B12 might be best. Cyanocobalamin should generally be avoided. Methylcobalamin, hydroxocobalamin, and adenosylcobalamin are all the active forms. Different patients do better with different forms. I would say that hydroxocobalamin is the most versatile form and probably best tolerated, but it is also more expensive. Methylcobalamin, most patients do well with. Some can be sensitive to it depending on their genetics, but it’s pretty readily available in sublingual forms and can make a big difference pretty quickly. You can start with that, or you could start with hydroxocobalamin drops if they have some sensitivity to B12 or methyl B12.