Gray hairs have more damaging chemicals like hydrogen peroxide and less of the protective enzymes that normally keep those chemicals in check.

As we age, our hair might turn gray because of a buildup of a natural chemical called hydrogen peroxide in the hair, and our body's ability to clean it up weakens — this messes with the pigment-making process in hair.

When too much hydrogen peroxide builds up in your hair follicles, it stops the pigment-making enzyme from working, which is why hair turns gray over time.

When the energy factories inside hair follicles don't work right, they make too many harmful molecules that damage the color-producing cells, making hair turn gray faster.

Scientists think that when there’s too much damage from natural body chemicals (oxidative stress) and not enough protection from helpful antioxidants, it might cause hair to turn gray earlier than normal.

As we age, damage from oxidative stress can harm the cells that give hair its color, especially because the body’s natural antioxidants weaken over time — this leads to grey hair.