If one took more then daily needed amount of b complex vitamins ie by supplements , will there be any side effects, or will the excess just be stored?

Listen to your body: B vitamins are water soluble and not stored. Excess makes urine yellow. They do require activation in the liver and taking excessive doses of some of the b vitamins such as b-6 can cause problems. Some persons need methyl folate (folic acid) and methyl cobalamine and b vitamins that don' t contain these forms may not be metabolized normally. Vit c with bioflavanoids and vit d3 may be needed as well.