It looks like it's called B100 because it has 100mg of each of the B vitamins. It's just a vitamin supplement that contains all the B vitamins in large amounts.
Thiamin (B1) 6667% RDA
Riboflavin (B2) 5882%
Niacin (B3) as Niacinamide 500%
Vitamin B6 as Pyridoxine HCl 5000%
Folate,
Folic Acid,Folacin 100%
Vitamin B12 as Cyanocobalamin 1667%
Biotin 33%
Pantothenic acid as d- Calcium Pantothenate 1000%
OK - this is only my opinion so take it as you will. Personally, I don't think 6000% of any single vitamin should be taken. Vitamin supplements claim all types of things, i.e. more energy, better gains, quicker recovery, etc. They say whatever they want to sell their product, but the fact is that the majority of claims are not actually tested and proven. Vitamins from food are better absorbed and high doeses of some vitamins can prohibit absorbtion of other vitamins.
Just an opinion though.
