How old do you have to be to take pre workout shakes?

What Kind? Protein shakes are not recommended in people younger than 18 years of age. Neither are energy drinks. If you want to boost your protein intake you can do it naturally with yogurt, nuts/nut butters, lentils/legumes, whole grains, and lean meats/fish. Be sure to eat a balanced diet with plenty of fresh fruits and vegetables in the mix.