What is the source of red color in the skin?

The red color in the skin primarily comes from oxyhemoglobin and hemoglobin. Hemoglobin is a protein found in red blood cells that carries oxygen throughout the body. When oxygen binds to hemoglobin, it forms oxyhemoglobin, which has a bright red color. This coloration is especially visible in areas of the skin where blood vessels are close to the surface. The more blood flow there is to a particular area, the redder the skin appears, which can be influenced by factors such as temperature, emotions, and physical exertion.

While melanin contributes to skin color by providing pigment that protects against ultraviolet (UV) radiation, it generally leads to shades of brown or black rather than red. Cholesterol is a type of lipid found in the body that does not directly contribute to skin color. Carotene, while it can impart a yellowish or orange color to the skin, does not account for the red hue. Therefore, the role of oxyhemoglobin and hemoglobin as the sources of red color in the skin is fundamental in understanding skin pigmentation in response to blood flow.