My b12 was low and i was put on supplements. it's been a year and i am still tired, my nails are brittle and have hangnails. am i still deficient?

For your physician: Only your physician can determine this using labs and he/she has an absolute duty to follow up with you on this aggressively. Especially when there is a problem absorbing vitamin b12, oral supplements are a poor choice compared with the injectable form. Being B12 deficient represents a serious danger to your permanent health & well-being, especially your nervous system.

Try Biotin for your : Try biotin 2000-3000 units daily for brittle nails and hair loss.