Why does a medicine have both a generic and a brand name?

Every medicine has a generic name, which identifies the active substance, and usually one or more brand names, which identify a particular company’s product containing it. Semaglutide, tirzepatide and finasteride are generic names; the products containing them are sold under various brand names.

The generic name is the more useful one to know. It stays the same across manufacturers and countries, while brand names differ, and it is what you will find on reference sites such as MedlinePlus. It is also how you avoid accidentally taking the same active substance twice under two different product names.

If you are unsure which is which on a box you have been given, a pharmacist can tell you immediately. It is a quick question and a genuinely useful one to be able to answer about anything you take regularly.