Switcvhing from oral finasteride to topical finasteride

If half-life of fin is 6-8 hours in the blood but 5-6 days in tissue (scalp) why don’t people apply topical every 3-4 days to minimize systemic?

Topical finasteride goes systemic. Perfect Hair Health has shown the relationship between systemic DHT level drops with higher and higher topical finasteride dosages as the effective topical dose increases. For men highly sensitive to finasteride, the standard topical finasteride will not change their problems by switching unless it is the liposomal preparation. Tissue levels remaining after stopping finasteride.  Officially symptoms’ like sexual side effects should disappear within 6 days, but from my experience, it can last a month or more.