Final answer:
Finasteride is an example of a 5 alpha reductase inhibitor, which is used to treat benign prostatic hyperplasia and androgenetic alopecia by blocking the conversion of testosterone into dihydrotestosterone.
Step-by-step explanation:
An example of a 5 alpha reductase inhibitor is finasteride. This medication is commonly prescribed for the treatment of conditions such as benign prostatic hyperplasia (BPH) and androgenetic alopecia (male pattern baldness). It works by blocking the conversion of testosterone into dihydrotestosterone (DHT), which is a more potent androgen responsible for the enlargement of the prostate and hair loss in men. Finasteride can be taken orally and is known for its efficacy in reducing the symptoms associated with BPH and slowing hair loss.