White hair happens when your hair follicles lose melanin, the pigment that gives your hair color. If your hair is turning white at a younger age, it could be caused by genetics or an underlying health condition.

It’s not uncommon for your hair to change as you get older. As a younger person, maybe you had a full head of brown, black, red, or blonde hair. Now that you’re older, you may notice thinning in certain areas of your head, or your hair may change from its original color to gray or white.

White hair is more noticeable in people with a darker hair color. Although white hair is characteristic of aging, colorless hair strands can appear at any age, even while you’re still in high school or college.

Hair turns white when your body stops producing melanin. Melanin is what gives your hair color.

It’s possible to restore pigmentation in your hair, but it depends on the cause. This article looks at six common causes of premature white hair.

Your genetic makeup plays a big role in when (or if) you develop white hair. If you notice white hair at an early age, it’s likely that your parents or grandparents also had graying or white hair at an early age.

You can’t change genetics. But if you don’t like the way your gray hair looks, you can always color your hair.

Everyone deals with stress from time to time. The consequences of chronic stress can include:

Stress can also affect your hair. A 2020 study found that stress can cause hair to turn gray prematurely by affecting the stem cells responsible for regenerating hair pigment.

This explanation might explain why some world leaders appear to age or go gray faster while in office.

An autoimmune disease can also cause premature white hair. This is when the body’s immune system attacks its own cells. In the case of alopecia and vitiligo, the immune system can attack hair and cause loss of pigment.

Hormonal changes caused by thyroid disorders, such as hyperthyroidism or hypothyroidism, may also be responsible for premature white hair.

The thyroid is a butterfly-shaped gland located at the base of your neck. It helps control many bodily functions, such as your metabolism.

The health of your thyroid can also influence the color of your hair. An overactive or underactive thyroid can cause your body to produce less melanin.

White hair at an early age can also indicate a vitamin B-12 deficiency. This vitamin plays an important role in your body. It gives you energy, plus it contributes to healthy hair growth and hair color.

A vitamin B-12 deficiency is associated with a condition called pernicious anemia, which occurs when the body can’t absorb enough of this vitamin.

Your body needs vitamin B-12 for healthy red blood cells, which carry oxygen to cells in your body, including hair cells. A deficiency can weaken hair cells and affect melanin production.

There’s also a link between premature white hair and smoking. An early 2013 study found a connection between the “onset of gray hair before the age of 30 and cigarette smoking.”

A more recent 2024 study also found a link between smoking and gray hair.

It’s well-known that smoking cigarettes increases the risk of lung cancer and heart disease. The long-term effects, however, can go beyond the heart and lungs and affect hair.

Smoking constricts blood vessels, which can reduce blood flow to hair follicles and cause hair loss. Additionally, toxins in cigarettes can damage parts of your body, including your hair follicles, causing early white hair.

White hair is part of the normal aging process, one that you can’t prevent. However, if your white hair is due to an underlying condition, treating that condition may help slow or stop its growth.

For example, treating a vitamin B-12 deficiency or an underlying thyroid disorder may increase the amount of melanin (pigment) in your hair follicles, reducing the growth of white hair.

The American Academy of Dermatology also recommends the following to slow the growth of white hair:

  • adopt a healthy lifestyle
  • eat a balanced diet
  • get a good amount of sleep
  • don’t smoke
  • manage stress
  • protect your skin and hair from the sun’s UV rays

A number of factors affect when you may start to see white hair growth. These factors include:

  • genetics (when your parents’ hair started turning white is a good indicator of when your hair will begin to turn)
  • ethnicity
  • chronic stress
  • nutrient deficiencies

That said, by the time most people reach 50, a large portion of their hair may be white.

The most common cause of white hair growth in younger people (high school and 20’s) is a vitamin deficiency. Deficiencies in iron, vitamin B-12 or D-3 can reduce the amount of melanin (pigment) in your hair follicles, causing the growth of non-pigmented or white hairs.

The primary causes of white hair are aging, genetics, stress, vitamin deficiencies, smoking, and underlying health conditions.

The ability to reverse or prevent white hair depends on the cause. If the cause is genetics, there isn’t anything you can do to prevent or permanently reverse the color change.

If you suspect a health problem, consult a doctor to see if an underlying condition is responsible for white hair. If you treat the underlying health problem, pigmentation may return, but there are no guarantees.