Q: I have been on finasteride for about 7 months. After my latest haircut I can see that my scalp is shiny. I read that is from sebum buildup and it can cause a layer that clogs the growth of hair. I was wondering if this is true and, if so, how can it be treated? — T.C., Philadelphia, PA

A: It is not true. Hair loss is caused by the miniaturizing effects of DHT on the hair follicle, not by blocked pores.

For more on this topic, view our pages on the causes of hair loss in men or the causes of hair loss in women.