As our body ages, we see changes in our hair texture for reasons both known and unknown.

A child with silky fine hair may have a head full of kinky curls when puberty hits. Another baby may start out with fine ringlets only to have them turn stick straight when she gets older.

As our body ages, we see changes in our hair texture. The hair of a newborn is very soft and very fine. The diameter of the hair thickens as we enter childhood or early adolescence. As we move into adulthood and then older, the hair again changes, becoming finer again in our 40s and 50s. All of these changes are genetically programmed.

"Hair changes every five to seven years," said Christo of the Christo Fifth Avenue Salon and creator of the Curlisto line of hair products.

But even though we might know what affects hair texture, it is still unclear exactly how and why this happens. People with curly hair have a flatter follicle. Straight hairs tend to have a rounder follicle. But how a flat follicle turns round, and vice versa, is a mystery.

"What adds to the curl or takes away from the curl is a fascinating issue scientifically," says Tom Dawson, a principle scientist at P&G Beauty. "You'd think with something as fundamental as human hair, and the amount of time and money we put into our hair, that we'd know more than we do. But it's a tough nut to crack.

"What is known is that hormones have a major effect on hair texture. Hormones influence the hair in several different ways since they are regulators of the body's metabolism," Christo says. "Hormones tell our body how to perform, therefore increasing or decreasing specific hormones can directly affect the way our body functions."

Hormones and your hair

He cites three major hormones that affect the hair:

Thyroxine and triiodothyronine

Thyroxine and triiodothyronine are produced by the thyroid gland and influence the way the body uses the food we eat. An under-active thyroid can cause brittle hair and hair loss.


Androgen is produced in the adrenal glands and is responsible for hair growth. In women, an increase in the production of androgen causes thinning of the hair and excessive facial hair.


Insulin is produced in the pancreas and is responsible for the adaptation of glucose in the blood. Under-production of insulin can cause hyperglycemia and over-production can cause hypoglycemia, which can both cause hair loss and change the way the hair looks and feels.

Hair after chemo

Cancer patients often find that after chemotherapy, their once-straight hair grows in curly. Chemo affects rapidly growing cells more than slowly growing ones, and hair follicles in the scalp grow rapidly. They are jolted by the chemo, and when they go back to work, they may have a new job description, says Dr. Jennifer Griggs. Over time, the hair follicle tends to return to its normal shape.

With little scientific evidence available about how hormones and genetics cause these texture changes, Jonathan Torch, creator of Curly Hair Solutions and founder of Toronto's Curly Hair Institute, has come up with his own theory.

He believes changes in the muscles at the base of every follicle are the key to the changes in hair texture that take place over time. These muscular changes, he says, often come during puberty, chemotherapy or menopause, when hormones and medications may affect the muscle tone.

Sometimes these changes can be extreme, says Torch, who has witnessed many a client go from curly to straight and straight to curly."I can't prove anything medically," he says. "But I have a philosophy that genetically, the muscles are changing. And this changes the shape of the follicle."

Much like the changes we experience with our skin as children through puberty and into adulthood, hormonal changes in hair texture are a normal and natural process throughout the course of a woman's life.

Have you seen a drastic change in your hair? Did it grow curlier or less curly with age? 

This article was originally published in December 2007 and has been updated for grammar and clarity.


As co-founder of, a website for curly hair she began with her business partner and friend, Gretchen Heber, Michelle Breyer helped create the leading community and resource for people with curly hair. Frustrated by the lack of information on curly hair and the limited products available in the marketplace, the duo launched the site in 1998 with the help of a 14-year-old web designer. When Procter & Gamble called three years later to advertise to the® audience, Breyer knew they had indeed created a force in the industry, providing helpful information and unparalleled expertise for what was then considered a niche market.

Story of my life! Now that I'm a wavy, it's not like I hate it, thanks to NC, but sometimes I miss my thick, straight, black hair. I think it looked a lot better when it was wet, and I didn't have to do anything to it to make it dry the way I want. :-(

Well, now I'm 4a, maybe some 3c. I had been getting relaxers since I was 7, but when I was a baby (like up until a year old), my hair is stick straight. My mom said it wen from straight to kinky in a strange

I have the same problem.. I had preety wavy hair. Like type 2 hair. NOw my is like a 3b and 3c type... I wonder why my brother hair has not change in texture... He is still straight and wavy....

now i have curly hair agaiin. but mine is weird. it is pretty curly long, but its like a really wavy with a curl to it, but when its short its realy super curly. so its kinda

When I was a baby I had fine 3b/3c curls lol this article just reminded me of that. I got older and had a relaxer it wouldn't really take but I'd have thick 4b/c hair at the roots. I transitioned and after my bc 5 years ago I had still kept thick 4b/c hair. 3 years ago it began to thin. Partly cause of scalp meds but I quit taking them. And now it's better but I have 3c curls again. I was freaking out thinking I was loosing hair but I think it's really just my texture from baby days returning. Thanks for this article

well first off i like to say that klin is right. whenever somebody who has curly hair goes to get their hair cut the barber only really wants them to get a trim. that way you can see their curls better. like when i went to get my hair cut she was telling me i had gorgeus locks. anyways since i was a baby i had very curly hair. even just looking at pictures of me you could tell it was curly. then when around the prek years through third grade i had really thick hair and it wasnt too curly was a 2a or 2b more. in fourth grade it got curlier and now it is about a 2b. so i like having curly hair. also my cousin who was born about three or two months earlier because her mom was sick had just kind of hair that sorta flipped but now its curly.

When I was little I had lots of ringlets, and was known for my adorable curly hair. I didn't like it, and always wanted my hair straight. In 2nd grade I got my hair cut, which should've made it curlier. For some reason, it got straighter, and was wavy through the 7th grade. I'll be in 10th grade this school year, and somewhere along the way my hair has developed a dual personality. On the lower layers of my hair, it's very wavy, and there's a few loose curls. However, it keeps getting straighter from there, and the top layer is almost board straight. It's awful, I wish my hair would either be curly, wavy, or straight, not all three. It might have something to do with the flat iron I've been using since 4th grade, more frequently through the years, until daily in the past three years. That's my messed up hair.

I had stick straight hair when i was younger and then when i was about 9- 10 years old it started to get thicker & what my granny called "body". but that's it and then when i was between 15-16 i let my hair grow out and it was a not too thick but not thin wavy hair. and if i cut my hair short it is like "poof!". and no one even really knew my hair was like that if they hadnt saw me in a year since it was stick straight when i was little. and i'm the only one in my "main" family that has the curly hair.


My hair has been really weird. It used to be SUPER curly when I was a baby, but there are also photos of me as a toddler where it was pin straight. Then it went kind of straight/wavy (maybe because I brushed it all the time) when I was a preteen. Then it went 3a curly as a teenager, and I'm 15 and it's starting to be WAVY again but curly in the front! Make up your mind, hair! ;)

I was born with pin straight hair, then about a year or two ago - BAMB. 2b hair! But, then again, that's when my little red friend started to visit. ;o

yaaa when i was a baby i had cute curly strawberry blonde hair. then it turned straight! lol. it got wavy when it grew though. now its curly again! lol. i wish it would make up its mind. but i like it curly. lol

When I was 6, my hair was wavy and up to my butt. But, when I turned 7, my hair started to get really thick and dry. Now, my hair is curly but pretty :)

I've always had wavy hair, but then around age 13 it got curly. xD

i had curly hair when i was a baby. then when i got my first hiar cut and then my har started to become thick and straight. and acoding to that guys theory he siad it had somethin to do with pubery and cancer and stuff and iv never gone through that

I was born with very little red hair pin strait. As I got older my hair of course browned out to a honey brown, but stayed thin and horribly strait. I was a mothers worst nightmare I had a tender scalp and then very tangly hair my father dubbed it a rats nest. So to keep some form of control my mom kept it in a bob. I hate short hair. As I became a teenager my hair darken even more and manged to get a red tent (in the proper lighting.) and right before high school my rats nest frizzed then curled. Not waved but loose ringlets. I was so relived, my hair has grown out considerably now and my favorite question years down the road and I have heard it too many times to count " Is your hair real?" I of course want to respond of course not its a wig. I hate hearing people complain about wanting straite hair after having lived both extremes I would take my curls now over any cut of strait hair. Also you have to love the hair dresser refusing to change your hair besides a trim. Strait hair never gets that.

I was born with pin-curls. Struggled with strong waves that bulged to the left in grammar school.Then in high school I had beautiful waves that complimented long layers. Now in my RAGING HORMONE 50s, I'm shocked. Strong S waves, tight waves framing my face. FRIZZIES!!!!!!!!! I don't know what to do! I love this web site! I'm learning how to handle my NEW hair.

now i know my hair type. thnx to you guys. when i was young as my mother relates, i have a wave my hair but also doubting because my hair is getting like 2B after scrunching it after shower and drying it with diffuser but without any chemical. but sopmetimes it is only slightly wavy. so what do you think is my hair type now?

Wow! I didn't know this was so common! I was born with blond ringlets, but had straight dark hair by the time i turned 2. It was 7th grade for me when my hair went curly (unfortunately at the same time as I first decided to cut my hair short!). High school introduced the reign of the flat-iron, but now that I'm 20 I finally have beautiful curls I love. Many many thanks to the ladies on here who corrected my ways - my straight-haired mother was helpless. I really hope my curls don't fade again. That would be a shame!

When I was first born there are picture of me looking like an asian baby. Slanted eyes, jaundice skin and a full head of fine pin straight jet black hair. By the time I was 6 months it had become a frizzy mop of black curls. Slowly I lost those curls and by the time I was 3 my hair was sporting straight sandy blonde locks. My wave slowly returned as I got older and my hair started to darken again, but it's only in the last few weeks that the real curls have made themselves known (age 19) though thankfully they're a bit softer and more manageable than when I was an infant. Everyone's thinks i've had my hair permed and they're all saying how much they love it! xD

I was born with really pretty wavy hair that turned into tight corkscrew curls when I was about 15 years old. It was BEAUTIFUL!!!! I was blessed to enjoy this hair until I gave birth to my first child at 21. After that, my hair started to get straighter and straighter. Now that I am done having kids, I have some hair that is wacy & some that would be considered loose borticelli curls. I miss my old hair & would do just about anything to have it back.

Hey Kara! I know exactly what you mean! When I was in 6th grade, my straight/slightly wavy hair turned massively curly, thick, and frizzy. I had no idea what was happening or how to control it! I'm a freshman in college now, and I've learned to love my curls. Thank you Michelle for posting this! It's always been a mystery to me as to how this happened! :)

Ha: up until about sixth grade, my hair was STICK STRAIGHT, and then in sixth grade it got REALLY thick and frizzy, and now i'm in eighth grade with really nice curly hair thanks to naturally curly!! :)