看看这篇

https://www.justvitamins.co.uk/blog/cyanocobalamin-versus-methylcobalamin/#:~:text=There%20are%20two%20forms%20of,is%20therefore%20obviously%20naturally%20occuring.

能知道常见两种型式的B12各有其效果，应该按每个人的状况、需求来选择。

要是搞不清楚自己确实需要什么，可考虑复合型，如这种

https://www.amazon.com/NOW-B-12-2000-mcg-Lozenges/dp/B001QNPWGM

剂量有点大，适合血B12低时快速补充。一周后改为隔日一片。