It’s still unclear to what extent the lower systemic [finasteride] exposure translates into a lower risk of side effects. Although sexual side effects did not occur more frequently than with placebo…due to the small patient collective…hardly any reliable statements can be made. However, such side effects must always be expected. Although topical finasteride is not approved as a medicinal product in the USA, it is marketed as an over-the-counter medicinal product through telemedicine portals such as forhims.com. In this context, the Post-Finasteride Syndrome Foundation, when asked by the DAZ editors, points out that they are also aware of numerous cases of [PFS from] topical application.
—Hair Growth with Consequences: Deutsche Apotheker Zeitung, March 10, 2023