Final answer:
Hair that is gray or white reflects a decrease in natural pigment, specifically melanin, which diminishes with age. Different amounts of eumelanin and pheomelanin, determined by genetics, decide natural hair color. Artificial hair coloring can also change hair color but does so by altering hair's structure or coating it with dyes.
Step-by-step explanation:
The color of hair that has a decreasing amount of natural pigment is typically gray or white. This change in hair color occurs as a result of a decrease in melanin production, which is the pigment that gives hair its color. Melanin is produced by melanocytes found in the hair papilla, and its production decreases with age, leading to the loss of color in hair.
Hair gets its diverse hues from the two types of melanin: eumelanin and pheomelanin. Darker hair contains more eumelanin, while lighter hair has less. Over time, as melanin production slows down, the hair can change color and eventually turns gray or white. This is a natural and genetically determined process.
Changes in hair color can also be achieved artificially through hair coloring. Permanent hair coloring alters the hair's structure by removing the natural color and replacing it with synthetic dyes. Different hair coloring methods, such as semi-permanent dyes, are less impactful but also fade over time as they do not alter the hair's natural pigmentation as much.