What is the cause of blackheads?

Understanding the Formation of Blackheads

Blackheads occur when a blockage or obstruction forms at the opening of hair follicles on your skin. Each follicle is accompanied by a hair and a sebaceous gland that secretes oil. This oil, known as sebum, plays a vital role in maintaining skin softness. When dead skin cells and oils accumulate in the follicle's opening, they create a bump referred to as a comedo.