Why does Hair Turn Gray As We Age?

S. Scolari

Hair turns gray as people age because the follicles at the base of the hair shaft cease to produce 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 black, brown, blond, red or any shade in between. The darkness or lightness of the hair depends on how much melanin each strand contains. Melanin is the same pigment that makes skin more tan with continued exposure to the sun.

Smokers are believed to gray at an earlier rate than non-smokers.
Smokers are believed to gray at an earlier rate than non-smokers.

The Graying Process

With age, the pigment cells in a hair follicle gradually die off. As they do, that strand of hair will no longer grow in with as much color and will show up as more silver, gray or white as it continues to grow. Eventually, if all the pigment cells die, the hair grows in completely gray. The graying of a full head of hair typically occurs over a long period of time. From the time a person notices the first gray hair strands, it can take 10 years or more to complete the process.

Many people show their first gray hairs during their late 30s or early 40s.
Many people show their first gray hairs during their late 30s or early 40s.

Genetics and Timing

The age at which a person gets gray hair is determined by his or her genes. A general estimate can be made by observing the ages at which his or her parents or grandparents went gray. Some people go gray at young ages — sometimes in their teens — and others might not go gray before age 50. Many people show their first gray hairs during their late 30s or early 40s.

Eventually, as pigment cells die, hair goes completely gray.
Eventually, as pigment cells die, hair goes completely gray.

Other Causes

Genetics is the most common cause of gray hair, but other things can contribute to graying, including a poor nutrition and a lack of B vitamins, particularly pantothenic acid. Anemia, which is the lack of iron in the blood; thyroid problems; and even smoking also can contribute to gray hair. Smokers are believed to gray at an earlier rate because smoking depletes oxygen in the body's tissues. Some treatments for diseases, such as cancer or acquired immune deficiency syndrome (AIDS), can cause hair to turn gray.

Genetics are the largest factor as to when an individual develops gray hair.
Genetics are the largest factor as to when an individual develops gray hair.


Some theories about gray hair have been determined to be myths. For example, it has been said that a sudden shock or fright can cause hair to turn gray overnight, but that theory has been discredited. Although parents often like to claim that the stress of having children has caused them to get gray hair, this theory also has been discounted.

Anemia can contribute to gray hair as a result of an iron deficiency in the blood.
Anemia can contribute to gray hair as a result of an iron deficiency in the blood.

You might also Like

Readers Also Love

Discussion Comments


I am 78 years old and have dark brown hair, with a

few grey strands at the front. My hairdresser thinks it is going darker!


I am 13 years old and my pubic hair is growing in gray. I'm afraid to tell my parents and I keep shaving it off. My boyfriend thinks it's cute but truthfully, I'm a little freaked out by the whole thing.

When I was eight years old, I saw my older sister's pubic hair and it was also silver. Should I be worried? Is it safe to dye my private area? Does anyone else have this?


@anon277916: Absolutely. Especially if your parents or grandparents were gray a little early.


Is it normal to get a greying goatee at 33 years old?


Does the age of one's parents at birth determine how early someone will go gray? I have heard that if the parents were older when someone was born, he'll start having gray hair earlier than his peers born to younger parents. Is this a myth or a (proven) fact?


I'm 54 and I have a few gray strands but most of my hair is still light brown. I also tan easily and have olive skin. I've heard that red haired people don't usually turn gray but only brown. Is this true?


I'm 29 and I first discovered a grey hair when I was 23. It is taking quite a long time for my hair to change color. In seven years (no dyeing, except a few highlights a couple of years ago), I have had most if them show up on either side of my head, for the most part around my temples, but nothing even noticeable. I still need to look through my hair to even find them. At this rate, I don't expect to be fully grey until I'm in my late 40's or 50's!


I am a 64 year old female with not one grey hair. My hair is dark, dark brown. In my youth and up until my late forties it was medium, reddish brown. Now the red is gone. It is healthy and shiny. Even my hairdresser has trouble understanding why I have no grey. Are there reasons or explanations for this? My parents both began greying in their fifties. Stress has always been an enormous part of my life. So if nothing else, I am living proof that stress does not cause grey hair. Just trying to understand.


I am 78 with silver hair. Why are the dark strands appearing?


I turned started turning grey when I was 16. I am now 37 and much of my hair is grey as well my beard, but my 26 year old fiance loves it!


My question is the same as anon32406: Does hair actually "turn" gray or does hair "grow" in gray? I have gray hairs that appeared over night and they are pretty long -- gray hair I would have notice before. Hopefully I get an answer!


I'm female and 72 and so far, the only gray I have is a a little bit on the crown of my head, and nowhere else. I can remember that my mom when she was in her 70's, hardly had any gray hair at all. I guess I can chalk no gray hair up to genetic. Also, I've had no hair under my arms or legs for well over 20 years -- must be the same reason.


I'm 70 next month and apart from a few grey sideburn hairs the rest is mid brown. My brother turned grey at 55, my dad about 50 but all of us have a bald patch. Interestingly, most people think me five to 10 years younger than I am.


I am 64, male and no grey hair. I tan very quickly, so I guess it's the Melanin issue discussed above. I am not complaining.


My hair seems to be turning black and coarse. It feels like fishing twine. Why does it do this? My hair is normally medium brown.


I'm 71, i have a few grey hairs in my sideburns.


I am 14 years old and my hair color is white (or gray). Why?


How can I get my hair to turn gray quickly as opposed to just salt and pepper besides coloring.


Just color your hair if you don't like the gray look. Science can't bother about gray hair remedies, with all the life threatening diseases to cure.

Be lucky you're healthy and only gray. When diseases are finally erased, then science can concentrate on curing our gray hairs. -anon1250


I was 38 and had dark brown hair. I was bald for a year doing chemotherapy and all my hair grew in white and gray. Bizarre!


my hairs are turning grey very fast. Do new hairs grow in grey?


Ah, I don't care if scientists say we can't blame our children for our gray hairs. any mom can tell you differently. For my part, I wouldn't dare color them, because I figure I've earned every one.


i'm 56, have long blonde curly hair, not a grey one in sight.


My first gray was around 24. I'm now 29 and my beard is about 50 percent gray but there are only a few grays on top of my head. Why is this? It makes me look a lot older than i really am.


I'm 62 and have only a few grey hairs in my sideburns the rest of my hair is mid brown. My mother and sisters were all grey by 40s-why is mine still the same as when I was young?


I got my first gray hair when I was 15 years old (I'm Caucasian), now I am 22. does that mean that my hair will turn gray completely in the next few years? "it can take ten years or more to complete the process"


I am 62 and have a white beard and grey/white hair. Recently I have found black hair growing in my beard. this is a bit distressful as the Christmas Season is approaching and I'm Santa. When I was young my beard was red?


>how does a single entire strand of hair suddenly become grey? No! This cannot occur. Hair is made by extrusion.. and hair is not alive. Hair does not consume food blood or breathe oxygen (oxygen would bleach it), it does not need vitamins or fruit flavors, as there is no biological process occurring in hair after it is formed in the follicle. The substance of the hair is pushed out of the hair follicle as a protein. it's like the plastic of your toothbrush. and this substance stays the same color, except at the end of long hair where it might become damaged. (leg split appear a different color.)


Today I pulled out a hair that was brown on top and gray in the root and right next to it was a hair that was gray on top and brown in the root. They were both half and half. Can gray hair turn dark again after it's gray or am I a mutant? What other powers do I have?


Does hair actually 'turn' gray or do new hairs grow in gray?


Anon5330, Your hair can turn a lighter color from the sun's radiation.. Or rays I'm not sure which.


Why does hair change colors. My hair used to be a dark brown and now it is a light brown. And i;m not even in my 20's yet.



how does a single entire strand of hair suddenly become gray?

Post your comments
Forgot password?