Appropriate Vitamins for 6 years old

Hello everyone, what vitamins would you recommend to my six year old boy. I want my child to be jolly in school as well as here in our house. I lately observed that he is always dizzy and it seems very tired when ever he got's home from school. I always ask him if her teacher gives a lot of activities in school but he says, It's not that many. As a parent, I want him to be active all the time.