The active ingredients in both of these drugs — finasteride in Propecia and minoxidil in Rogaine — work in very different ways to combat hair loss. Finasteride is taken orally and works at the hormonal level while minoxidil is a topical medication applied directly to affected areas of the scalp.
Finasteride inhibits 5-alpha reductase, an enzyme that promotes the conversion of testosterone into a potent androgen known as dihydrotestosterone, or DHT. DHT targets the hair follicle, gradually shrinking it in a process that leads eventually to baldness. Studies have shown that men who take finasteride daily reduce scalp levels of the androgen by as much as 60 percent.
Most hair loss can be traced to the miniaturization of hair follicles, a process that can be staved off or even reversed hormonally by taking finasteride. Topical minoxidil works directly at the hair follicle level, slowing or reducing the miniaturization process and slightly enlarging the follicles themselves.

AHLA cites evidence from clinical trials showing that 86% of the men taking the finasteride were able to stop the progression of hair loss. And 65% of participants in the clinical trials experienced a significant increase in hair growth, according to the association.

There are also numerous studies showing that Minoxidil is effective at promoting hair growth. In a four-month study, 74% of men judged that minoxidil improved their hair density, with 93.8% of study participants judging minoxidil as very effective, effective or moderately effective at stimulating new hair growth.

Yes, studies show that minoxidil and finasteride are safe to take together. Many studies have been conducted using finasteride and minoxidil together to prevent hair loss while fueling new growth of healthy hair. Your physician will recommend a personalized plan for you to use one or both of these treatments.

Finasteride and minoxidil typically take 3 to 4 months of daily use to start seeing visible changes. It can take up to a year to see the maximum results. Like all medications, finasteride and minoxidil will work differently for different people so it’s best to continue medication for one full year before deciding on whether the medication is doing all it can for you.