Does shaving your head improve the results of propecia and minoxidil?

This is a great question. Good studies have not been done to answer your question so one is relying entirely on clinical experience and rationale thinking. For finasteride, it is unlikely that shaving would have any benefit at all given that this is an oral medication. For minoxidil, shaving is also unlikely to give a difference in effect. However, one must be aware that the medication only works once it hits the scalp. So individuals with longer hair do require much greater care to ensure the appropriate amounts reach the scalp and not the hair. Otherwise, for someone not willing to apply diligently - shaving in this case will likely produce better results.