피나온, or finasteride, is a medication primarily used to treat male pattern baldness and benign prostatic hyperplasia. It works by inhibiting the enzyme 5-alpha reductase, which converts testosterone into dihydrotestosterone (DHT). By reducing DHT levels, 피나온 helps to slow hair loss and promote hair regrowth in men. This medication is typically taken in pill form and is available by prescription. While many users report positive results, it may also cause side effects, including decreased libido and erectile dysfunction. It's important for individuals considering 피나온 to consult with a healthcare professional for guidance and monitoring.