Blackheads, also known as open comedones, form when the opening of a pore becomes clogged (but not sealed) with sebum. The black you see isn’t dirt. Exposure to oxygen causes the oil within the pore to oxidise and become black. Blackheads tend to be more common in the T-zone (the forehead, nose and chin), as this area produces more oil than other parts of the face. Regular cleansing and exfoliation using AHAs (Alpha Hydroxy Acids) and BHAs (Beta Hydroxy Acids) can help to prevent blackheads forming.
