My pharmacist told me that the BP is only 90% effective after its expiration date. In this case that is 14.5 months to lose 10% effectiveness on the wash that I have. I don't know however at what rate the deterioration continues. She also said that it was basically just the BP that was loosing its effectiveness and that the wash was still save to use. So now that I know that it is safe and I have nothing to lose I'm going to give it a try.
I just decided to get serious about my acne again and found all my old 4% Benzoyl Peroxide facewash. It expired in '04. I was reading other posts and people vaguely said that BP lost it's effectiveness over time. Well how much? Does anybody know the Half life of BP? My acne is mild and I have six 6 oz. bottles left so i'd hate to pitch it. For now I'm going to try it and see what happens. If anyone has any advice or knows the half life let me know. I also plan to call my pharmacy. I'll keep y