I use to avoid cyanocobalamin because i thought it was bad and alwas stuck to sublingal methylcobalamin and b12 shots coming from crohns background. Then about a year ago i saw a video with my fav dr greger saying cyanocobalamin was the best absorbed form... so i switched to this. Must have been working because then i had a shot (with no bloods prior) and it shot up to over 1000. Dr was worried.. i told her to chill its good. In japan its upto 2000. Anything under 500 and they get a shot. Our "healthy range " is 120 - 400/600. Ridiculous!