Like anything else, it's important that you get to the root of the problem. Questions you should ask yourself are, "why did I go on birth control in the 1st place?". If it was to regulate your menstrual cycle, then the root cause of the menstrual irregularities is not been elucidated. "Has the PC OS diagnosis been confirmed?" Or was this just a physician's opinion based on inadequate/incomplete evidence.

In a 21-year-old female, hormonal irregularities are usually adrenal related but they can be from any other causes (too little body fat, not enough cholesterol (pregnelalone (sic), precursor) etc. Before you use something like Vitex, it may be a good idea to get at the root of the problems as this is the path to healing.

I'm sorry for being vague but there is simply not enough information in your post to give you a better opinion.

Dr. Armine

Jess P. Armine