What vitamins and supplements should a teenager take?

None: If you eat a balanced diet, no supplements are necessary.

Whole Food Vitamins: In general, vitamins made from whole foods (they will be labeled as such) are more easily absorbed and used by your body and are a better choice. These types of vitamins are generally only available at health food stores, both local and online. High quality Omega-3 fatty acids may also be of benefit.