My B12 level was 267 and according to one doctor that was considered "low". She told me to take a B12 dosage of 200 mcg daily. My regular doctor then saw me a couple of days later and stated he didn't consider it to be low. I took the regualr b12 vitamin supplement for a month and noticed no difference. Then as time went on, my symptoms were all still there (mental fogginess, sluggish memory, difficulty in concentrating etc). With all the talk regarding "low" levels, one being normal is 200-900, another being 500-1100 I thought well maybe it can't hurt to just take the vitamin b12, however, take it in the sublingual form which I read absorbs better. The only 2 doses I found on the market were 2500 mcg and 5000 mcg. So today I started taking the one daily under the tongue 2500 mcg. Can this hurt me?