What b vitamin is good for cholesterol?

None: There are no b vitamins that are known to lower cholesterol.

Vitamin B3: Vitamin b3, or niacin, is the only b vitamin that truly effects cholesterol. It reduces LDL (bad) and raises HDL (good) cholesterol. The caveat is that to be effective requires high doses (400mg +), wherein it should be considered a drug rather than just a vitamin. That's because at these high doses it can irritate the liver (liver enzyme levels should be followed) and cause muscle problems.