Q: What are your thoughts on topical finasteride? I am hesitant to use this because I cannot find any good studies on this let alone what the potential side effects may be with prolonged use.

A: Although there are no controlled studies to date, our sense is that topical finasteride in the right formulation may be a good therapeutic option. Long-term it should be at least as safe as the oral formulation.

However, presently, we don’t use topical finasteride for the following reasons:

1. The dosing and efficacy have not been worked out.
2. The topical formulations are not regulated and therefore not consistent in dose.
3. In order to be effective, topical finasteride must be absorbed to some extent in the bloodstream and so a similar side effect profile may exist as with the oral version.
4. It is not clear that using it topically can increase the efficacy/side effect ratio (i.e., depression of serum DHT levels may be important for its effect).
5. It may inadvertently be used by pregnant women.