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Why is my black hair turning blonde?

It’s not uncommon for people with naturally black hair to notice some of their strands turning blonde or lighter over time. There are a few potential causes for dark hair becoming lighter.

Sun exposure

One of the most common reasons black hair can turn blonde is sun exposure. The sun’s UV rays have a bleaching effect on hair melanin over time. People who spend a lot of time outdoors in the sun may notice more blonde strands appearing in their naturally dark hair.

The sun’s effects are increased if you have chemically treated or color-treated hair. The treatments make the cuticle layer more porous, allowing the sun to penetrate the shaft more easily and alter the melanin pigments. Wearing sunscreen and protective styles like hats can help minimize sun damage.

Hydrogen peroxide

Hydrogen peroxide is a common ingredient in hair lightening and coloring treatments. As a powerful oxidizing agent, hydrogen peroxide interacts with the melanin in strands to remove pigment and create a blonde effect.

If you use hydrogen peroxide hair dyes at home, overlapping previously treated areas can cause increased lightening. The overlapping applications may be lightening your roots faster than the rest of your hair, giving the appearance of new blonde growth.

Skin and hair lightening products

Some skin and hair lightening products work by inhibiting melanin production. With less melanin formed, new hair growth can be lighter. Skin lightening creams with ingredients like hydroquinone and hair products with cysteamine or rucinol can cause this effect over time.

Stopping use of lightening skin and hair products allows melanin production to return to normal. New hair growth will become darker again after discontinuing use of depigmenting chemicals.

Aging and hormonal changes

As we age, our hair can gradually turn more grey and white. This is partially due to reduced melanin production as hormone levels shift with age. The natural aging process may cause black hair to lighten or become blonde over time.

Hair follicles also produce less melanin due to declining enzyme activity as we get older. Enzymes play a key role in melanin production through melanogenesis. With less enzymes, melanogenesis slows, resulting in greying and lightening of hair.

Vitamin deficiencies

Some vitamin deficiencies are associated with reduced melanin formation, which can contribute to black hair turning blonde. Deficiencies in vitamins B12, E, and folate have been linked to loss of hair pigment.

Getting enough of these vitamins can help support normal melanin production. Eating a balanced diet with good sources of vitamins B12, E, and folate may help prevent depigmentation of hair due to deficiency-related causes.

Genetics and ethnicity

Ethnic background and genetics play a role in hair color. Some genes influence melanin production and how pigment translates to actual hair color.

People of mixed ethnicities may experience their naturally darker hair lightening over time. Having one parent with blonde hair can sometimes lead to slight lightening of darker hair later in life.

Medical conditions

In rare cases, an underlying medical condition could be causing black hair to turn blonde. Conditions like vitiligo, alopecia areata, and thyroid disorders may be associated with pigment loss and depigmentation.

If you are concerned about progressive hair lightening, it’s a good idea to see a dermatologist. They can check for any conditions that might be contributing to your hair color change.

How to prevent and treat dark hair turning blonde

If you don’t want your black hair to turn blonde, here are some tips to prevent and treat discoloration:

  • Limit sun exposure by wearing protective styles and hats when outdoors
  • Use sunscreen regularly on your hair and scalp
  • Avoid overlapping hair treatments and dyes
  • Discontinue use of hair and skin lightening products
  • Eat a balanced diet with good sources of vitamins B12, E, and folate
  • Use semi-permanent vegetable-based dyes to cover blonde spots
  • See a dermatologist if hair lightening becomes excessive

When to see a doctor

Consult a dermatologist if you notice significant and persistent lightening of your dark hair. A doctor can check for any underlying conditions and determine if the cause requires medical treatment.

See your doctor promptly if hair lightening is accompanied by other symptoms like hair loss, rashes, or changes in skin pigment. Rapid dark hair turning blonde could potentially indicate an autoimmune disorder, thyroid disease, or vitamin deficiency requiring treatment.


Discovering blonde strands in naturally black hair can be alarming but is often harmless. Gradual lightening of dark hair is common as we age. However, ruling out any medical conditions is recommended if hair depigmentation is accelerated or extensive.

While some causes of black hair turning blonde are unavoidable, like aging, others can be addressed. Adjusting hair care, diet, and sun exposure habits can help slow or stop the lightening process. With proper prevention and care, your black tresses can maintain their beautiful, dark color.