Would using rogaine (minoxidil) 4 mos. past its expiration date be a waste of time? how long would tretinoine be good for? retina , i mean.

Past expiration: The expiration date on meds give the time that they are the most effective.Past expiration, there is still prob some value--but of course drug companies will not give out that information--they would rather you purchase "new med" If the expiration date is less than 5 months, there is still value, for the meds you mention--go ahead. If the med would be for heart, hypertension, diabetes,etc--then NO