Why would you want to wear both at the same time?I can see where you would put the differin on at night and then benzoyl peroxide on in the morning.But why at the same time?Retin a micro is very drying on its own.Take care.:Ps,retin a micro can work differently on different people.For some people it can take up to 8 weeks to work or more.When i was on it i noticed an improvement in my skin in about month.I've might have been one of the lucky ones.Take care.