I am currently in medical school, but very interested in functional medicine. Can I start taking courses now or do I have to wait until I graduate?

We have quite a few medical/healthcare students who are concurrently taking our courses as they complete their degree programs and residencies. Those students usually take our courses as their finances and schedules allow, then once they have completed their degree programs and received their license they apply for our program thereafter. Any courses they took while they were in school automatically count towards their certification and they would not need to re-take anything.