Thanks for following!

If your digestion is healthy, 200mcg should be a good amount, bearing in the mind the low absorption rate. B12 can - and often is- taken in much higher doses and is indeed non toxic. Yes, if you dissolve it under the tongue it can help improve absorption, as it by-passes the stomach and enters the blood directly. Some people lack intrinsic factor, the protein secreted in the stomach needed to absorb B12., so this is a good alternative to injections.

If you are at all concerned, I recommend a homocysteine test.