That is the million dollar question??? I have heard so much about b12 and it not being effective as sublingual then I was reading a post from snozberry saying he had results from healthline.cc max stress b nano plex. I just started it last week I can't tell because I have been on b12 shots( and iron lots of it) since march ( roughly) so I had already got my energy back and my thinking had improved brain fog lifted, started exercising etc. so the b12 made a huge diff I just had to go to an MD to get a prescription. It was easy for me because of my other health issues ie she took one look at me and had her pad out saying you betcha b12 would hit the spot! Before I got a scrip I went to a body building site and found an injectable b complex from vet supply and ordered it for a mere 6 bucks but I chickened( no pun intended) out wondering (one) about the niacin and the flush and (two) what the hell would they put in there for animals farm animals that is???