Let me start straight off by telling you what comedogenic actually means. Blocked pores are called comedones. When a product is comedogenic, it means it has the potential to block pores. How does it do that? Well, by increasing the shedding of skin cells. These skin cells then combine with the sebum (or oil) in your skin and block your pores.
Now since acne is caused by blocked pores, these ratings would obviously matter a lot to people who have acne. We generally would want to avoid products that would potentially cause more blocked pores leading to more acne.
