Loss of Hair Pigmentation

Woman with very short gray hair
Q: What is the biological reason for loss of pigmentation in hair as you age?
A: As a part of the aging process, the various cells in our bodies break down and slowly decrease production or simply stop functioning in the way they are intended to function.
The cells of our body are constantly being replicated and replacing themselves. This is what allows our bodies to heal and allows us to grow in size from infant to adulthood.
The cells in our body are varied and differ according to the function they serve. There are cells of countless types in the human body and dozens of types of cells found in the skin alone.
Among these are cells that make up the thousands of follicles that produce the hairs on our bodies. Our hair follicles contain melanocytes which normally produce melanin. Melanin is the pigment that gives our skin and hair its color.
The cells of our bodies gradually break down after years of reproduction and replication. When the melanocytes break down due to age (the exact longevity of a particular cell is determined by genetic triggers and varies from individual to individual) it ceases producing melanin and the hair growing from the follicle will begin to grow white, losing its pigment.
Photo: Mimagephotography/Shutterstock
See also:
Pigmentation Aberration
Going gray
Gray hair and age
Why does gray/white hair turn brown when wet?