What causes the dark color in a blackhead?

The dark color in a blackhead is primarily caused by oxidation. When sebum, which is the oily substance produced by sebaceous glands, mixes with dead skin cells, it can clog hair follicles. If this mixture is exposed to air, it undergoes oxidation, which causes the melanin in the sebum and skin cells to darken. This process leads to the characteristic black appearance of blackheads.

While excess oil is a contributing factor to the formation of blackheads, it is not the reason behind their dark color. Similarly, a bacterial infection can lead to different types of acne, but it does not account for the oxidized black color. Dehydration may affect skin condition overall, but it doesn't play a direct role in the coloration of blackheads. The key aspect of blackheads that distinguishes them from other forms of acne is this oxidation process.