Legal Question - Over counter Medication Sales

All these pills you can buy offline and from TV Infomercials. I have some questions about the leagalities as I would like to consider the possibilities of going into buisness likewise. All these pills are similar as far as fat burners, athstma, uppers (effedrin basically); penis/breast enlareger, sex enhancers, etc… but just marketed differently. These are not FDA approved. Can I sell a pill, market it in my own way legaly to. Do I need to have a lab make the pill or can I sell an existing pill in my own packaging. (Its basically a combo of Vitamins) that will make you dream better and more vividly (really works too). What kind of obstacles do I need to tackle to do this? Thanks!