Hi, I have heard from a highly reliable source that sub lingual forms of B12 are just as effective as injections. I take two products from ProHealth: B-12 Extreme and Hydroxocobalamin Extreme. I have not been tested. Fyi, I am meeting with success with this form of B12 supplementing, folate, and AHCC (Immpower 3 caps 2 x a day)....in addition to everything else I take. I am a 35+ year patient, and am doing consistently well with PEM for the first time, now able to swim every other day for 30-45 minutes!