The difference in my health is unbelievable after buying this complex.Has everything you need to think better and look better. I buy the 10000 iu vitamin D with 10000 mcg of b12 and I take this on top. Pee out the extra b12 my body doesn't use or need. I'm addicted to buying natural supplements now and mother nature supplements have everything you could need. The Doctors keep the benefits of buying supplements a secret because they're safe and very beneficial. Unlike the terrible drugs I used to get off a Doctor, these have no side effects or fillers. So I was able to come come off most of my meds after I told the Doctor I'd prefer to go natural from now on. Thanks to mother nature I feel better, think better and look better now. The only negative I can think of with these B complex supplements is the amount of fat soluble b12 in them. Everything else is a perfect dose but in my opinion a little extra fat soluble b12 would be great.So I can stop taking thiamine supplements off my Doctor which smell and taste terrible.