I am on 5th day of taking accutane pills & I'm wondering if I can take Biotin, Keratin, and B12 supplements while on it?

The only supplements of concern are those that contain Vit. A since it would potentially raise the blood level of Retinoids overall including Accutane.  The supplements that you are concerned with should not be of concern.I hope this is helpful.Steve Greene, MD, Advanced Dermatology and Laser Institute of Seattle

Those should all be fine to continue.  We tell our patients to specifically avoid Vitamin A, except for the small amount in multivitamins, and otherwise most other medications except Minocycline are fine with accutane.  If your supplements are expired, they probably won't hurt you but may be less potent.  Remember that supplements and vitamins are not regulated by the FDA, so a lot of the things they claim to do are just advertising hype that has not really been proven.  Talk to your dermatologist about your other supplements just to be sure.