Hair gets its colour from melanin, and a decrease in melanin production can cause grey hair.
Stress can affect the stem cells that regenerate hair pigment, which can accelerate the greying process.
Chemicals in smoke can damage hair follicles, causing them to lose their pigment cells.
When the thyroid isn't functioning properly, hair follicles may stay in a resting phase instead of growing actively. This can lead to brittle hair, thinning hair, or hair loss.
A deficiency in vitamins B6, B12, or folic acid can cause hair to lose its pigment.
This condition causes hair to lose pigmentation in patches due to a decrease in melanin production.
Free radicals and reactive oxygen species in the atmosphere can cause oxidative stress on hair cells, which can lead to premature greying.