What is Vitamin B Complex 100mg Time Release (Mega Potency)? It is very difficult to get adequate amounts of the vitamin B complex from an average daily diet. Drinking high quantities of coffee or alcohol can increase the need for B vitamins. What Does Vitamin B Complex 100mg Time Release (Mega Potency) Do? Vitamin B Complex contains a selection of B vitamins, which help to release the energy from food in to your body, therefore it may help to maintain normal energy levels.