Smokers are believed to darken earlier than non-smokers.
Hair turns gray as people age because the follicles at the base of the hair shaft stop producing melanin. Each follicle contains a finite number of pigment cells. These pigment cells produce melanin, a chemical that gives the hair shaft (the visible strand) its color, whether it’s black, brown, blonde, red, or anything in between. The darkness or lightness of the hair depends on the amount of melanin that each strand contains. Melanin is the same pigment that causes the skin to tan with continued exposure to the sun.
The aging process
Many people show their first gray hair in their 30s or 40s.
With age, the pigment cells in a hair follicle gradually die. By doing this, that strand of hair will no longer have as much color and will turn more silver, gray, or white as it continues to grow. Eventually, if all the pigment cells die, the hair turns completely gray. The aging of a full head of hair usually takes place over a long period of time. From the moment a person notices the first gray hair, it can take 10 years or more to complete the process.
genetics and time
Eventually, as the pigment cells die, the hair turns completely gray.
The age at which a person turns gray is determined by their genes. A general estimate can be made by looking at the ages at which your parents or grandparents went gray. Some people go gray in their youth, sometimes in their teens, and others may not go gray before age 50. Many people get their first gray hair in their late 30s or early 40s.
Other Causes
Genetics is the main factor in determining when an individual develops gray hair.
Genetics is the most common cause of gray hair, but other things can contribute to aging, including improper nutrition and a lack of B vitamins, especially pantothenic acid. anemia, which is a lack of iron in the blood; thyroid problems; and even smoking can also contribute to gray hair. Smokers are thought to age faster because smoking depletes oxygen from the body’s tissues. Some treatments for diseases, such as cancer or acquired immunodeficiency syndrome (AIDS), can turn hair gray.
myths
Anemia can contribute to gray hair as a result of a deficiency of iron in the blood.
Some theories about gray hair were considered myths. For example, it has been said that a sudden fright or scare can turn hair gray overnight, but this theory has been debunked. While parents always like to claim that the stress of having children has caused them to go gray, this theory has been dismissed as well.