What Causes Gray Hair, and Can You Reverse It?

Written by Maria Robinson, MD, MBA | Reviewed by Sophie Vergnaud, MDUpdated on October 17, 2022

Key takeaways:

• For most people, getting gray hair is a normal part of the aging process. 
• Certain health conditions and lifestyle habits may contribute to getting gray hair early. 
• The age at which you go gray is also determined by your genetics. So, if you have a parent who went gray early, then it’s likely you will too.   
• It’s not possible to reverse or treat gray hair. But, with advancing research, this may be an option in the future.

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For some people, gray hair can be hard to deal with, no matter the age when it happens. While a few may embrace the color change, others may look for ways to prevent or reverse the process. But is it really possible to reverse gray hair? Are there things you could be doing to prevent this from happening?

Here, we’ll review how your hair turns gray, what medical conditions or lifestyle factors could be contributing to this change, and if it really is possible to reverse gray hair. 

Why do people get gray hair?

Whether we like it or not, getting gray hair is part of the normal aging process for many people. In fact, up to 23% of people will have half their hair turn gray by the age of 50.

For the most part, when you get gray hair — and how much of it you get — comes from the genes you inherit from your parents. “Premature graying” is a term used when hair turns gray earlier than expected, and it can be caused by some underlying medication conditions.

Let’s first review how hair gets its color, and then discuss when and why people’s hair may turn gray.

How hair gets its color

Hair color comes from melanin, which is a natural pigment found in different parts of your body, including:

• Hair follicles
• Skin (responsible for your skin color)
• Parts of your eye (responsible for your eye color)

There are two main types of melanin — eumelanin and pheomelanin. Your hair color depends on how much and what types of melanin you have in your hair follicles, which is determined mainly by your genes. 

Depending on these factors, hair color varies from person to person. It can be: 

• Blond
• Brown
• Black
• Red
• Something in between

Hair color can also change over time. For example, light-colored hair in children may get darker as they get older. We’re not exactly sure why this happens, but it may have to do with hormonal changes. 

When do most people get gray hair?

Each person is different, and the age at which someone typically turns gray depends on their genetics and ancestry. 

Here are some typical ages for turning gray among different groups: 

• White people typically start to gray in their mid-30s.
• People of Asian ancestry typically start to gray in their late-30s.
• People of African ancestry typically start to gray in their mid-40s.

What’s premature gray?

Premature graying happens when people gray earlier than expected. The age may vary from person to person, but premature gray is defined differently according to someone’s descent:

• White people are prematurely gray if they are younger than 20.
• People of Asian descent are prematurely gray if they are younger than 25.
• People of African descent are prematurely gray if they are younger than 30.

Experts are not sure exactly why people get premature gray hair, but it’s probably related to genes. If your parents had premature grays, you may be more likely to get them. Other factors may play a role (more on this below).

What causes gray hair?

As you get older, your hair follicles start making less melanin, which causes your hair to start growing in gray or white.

Experts are not exactly sure why this happens at different ages in different people, but the main reason is likely to lie in your genetics. In fact, scientists have found a specific gene linked to gray hair, although it’s likely there are many different genes involved. So, at what age your hair starts to turn gray (and how much of it does) depends mainly on the genes you inherit from your parents.

Oxidative stress

Oxidative stress is a cellular process that may also contribute to hair follicles losing pigment and turning gray. Oxidative stress occurs when there is an imbalance of free radicals (which can damage cells) and antioxidants (which can prevent or delay some cell damage).

Certain situations or chemicals might cause oxidative stress and speed up gray hair. But more research is needed to figure out exactly how: 

• People with gray hair can have high levels of hydrogen peroxide and low levels of catalase. The body naturally produces both of these chemicals, but catalase normally keeps hydrogen peroxide in check. So when levels of catalase are low, hydrogen peroxide can build up.  
• Inflammation in the body can be caused by periods of chronic or acute psychological stress. 
• Ultraviolet (UV) light, especially UVA and UVB from the sun, can increase the oxidative stress in hair follicles.

Other factors that may contribute to gray hair

It’s possible that some health conditions and lifestyle habits may be linked to getting gray hair, especially when it happens early. Examples include:

• Nutrient deficiencies (like low levels of vitamin B12 or ferritin, which can happen from low iron levels, among other reasons)
• Some genetic conditions (like tuberous sclerosis and acatalasemia)
• Thyroid disease
• Vitiligo
• Alopecia areata
• Smoking
• Psychological stress
• Certain medications (like chloroquine)

Can stress cause gray hair?

Stress has often been linked to getting gray hair. But science has only recently been able to back up this claim. A recent study showed that people who experience psychological stress were more likely to develop gray hair. It’s important to know that the study was pretty small, so we need more research to figure out exactly how this happens.    

Can sleep play a role?

So far, there’s no direct link between the amount and quality of sleep a person gets and whether or not they have gray hair. But not getting enough sleep contributes to increased stress levels. Since stress is linked to gray hair, it’s very possible that not getting enough sleep over a prolonged period of time can indirectly contribute to gray hair.

Can you prevent gray hair?

No, in general there is no way to prevent your hair from turning gray as you age. 

Eating a healthy, well-rounded diet is a good idea. This helps improve your overall health and decreases your risk of developing any nutritional deficiencies that may be associated with graying too early. 

It’s possible that lifestyle changes — like smoking cessation and lowering your stress levels — could help prevent premature graying. So far, though, there’s no definitive evidence to prove this. But research shows that these two lifestyle changes improve other aspects of your health, so they may be worth doing anyway.

Can gray hair be reversed?

Until recently, the answer to this has been “no.” It was thought that once a hair follicle stops making melanin, it wasn’t possible for it to regain its color on its own.

But a recent study showed that it may be possible to reverse gray hair — even if just temporarily.

In the study, researchers were able to analyze how individual hair shafts changed over time. They showed that stress was linked to hairs turning gray, and when that stress was removed, some color was restored in some parts of the hair. 

The study involved a small number of people, and the changes in hair color were subtle and only seen with a high-resolution scanner. But they provide evidence that turning gray may not be a fixed process. 

It’s hard to say for sure what this means for individual people — if anything — since everyone’s situation and genetics are unique. 

Are there gray hair treatments?

There are no treatments that are proven to treat (or reverse) gray hair. As researchers learn more about how the graying process happens, they may develop effective medications and treatments for gray hair. 

For now, the best choice for people who want to cover their gray hair is to use hair coloring, which can be temporary or permanent depending on the type.

Or you can ditch the hair dye and opt to gray naturally and gracefully.

Are there natural remedies that slow hair from graying?

So far, there are no natural remedies that can slow down the hair-graying process. The best thing you can do is to stay healthy, eat a well-rounded diet, and lower your stress levels as much as possible.

What are other myths about gray hair?

There are many other myths about gray hair that you may have heard. Here are some common ones that are not true:

• Coloring your hair leads to faster loss of color.
• Plucking gray hair leads to multiple gray hairs growing back.
• Laser hair removal can get rid of gray hairs.
• Bleaching your hair causes gray hair.

The bottom line

Getting gray hair is part of the normal aging process, and different people will experience it at different ages. There are certain health conditions and lifestyle factors (like smoking and stress) that could contribute to going gray earlier. As of now, there are no effective treatments that can reverse or prevent gray hair. New research shows that gray hair may be reversible to a small extent, but more studies are needed to look into this question further.