RENEE MONTAGNE, host:
Onto other hair news now. Plenty of you have straight hair and want curly hair. Others have curls and straighten them out. But a few people have hair that actually changes on its own, and not just because of the weather. NPR's Jessica Goldstein reports.
JESSICA GOLDSTEIN: Kimberly Fasting-Berg, a marketing executive in New York, has hair issue.
Ms. KIMBERLY FASTING BERG (Marketing Executive): Every seven to 10 years, my hair tends to change texture, going from straight to wavy to curly. I can't predict it. It just happens to me and I'm like, oh, here we go again.
GOLDSTEIN: This also happens to Judy Butler, a midwife in Arizona. So when she saw changes in the hair for three kids, she wasn't surprised.
Ms. JUDY BUTLER (Midwife): My first two were very straight hair as infants; I mean stick straight. And then when they got to be 13, 14 years old, whenever they hit puberty, the boys a little bit later, my daughter right around 13, became very curly, very wavy, and very frizzy.
GOLDSTEIN: I've always had curly hair, so I wondered: how often do hair change? Could it happen to me? I set off on a quest to find out. First, I called Barry Starr, a geneticist at Stanford University. He told me most people's hair won't switch between curly and straight.
Dr. BARRY STARR (Stanford University): If your mom gives you a curly version of the gene and so does your dad, you end up with curly hair. If both parents give you the straight version, you end up with straight hair. But if one parent gives you the curly version and one parent gives you the straight version…
GOLDSTEIN: You could wind up with something in between. But he couldn't tell me why some people go through a hair transformation.
Mr. STARR: It's an interesting genetic question, but I don't think there's an answer yet, and there may not be.
GOLDSTEIN: The next person I called is Dr. Paradi Mirmirani. She is a dermatologist in California specializing in hair.
Dr. PARADI MIRMIRANI (Dermatologist): We do know that curly hair has a different shape than straight hair.
GOLDSTEIN: And that shape depends on the shape of the hair follicle. This tiny structure guides the hair fiber up a sort of tube as it grows. The inside of the tube determines if the hair is curly or straight.
Dr. MIRMIRANI: Curly hair is oval as it exits the scalp, whereas straight hair is circular as it exits the scalp, and it remains straight.
GOLDSTEIN: I try to work it out. Oval strands give you curly hair?
Dr. MIRMIRANI: If you think about gift-wrapping ribbon, when you try to make it curly you take the scissors and you flatten out the one side and it curls. So you're changing the shape of one side compared to the other. So when it's oval, one side is curved and the other side is flat, which makes it curl.
GOLDSTEIN: Ah. So if your hair changes from straight to curly, it means the follicles must have changed shape. So what could make that happen? Mirmirani didn't know. Maybe hormones? After all, hair changes in other ways during adolescence or after having a baby.
Dr. VAL RANDALL (Bradford University): Hormones are a logical guess, but I have no evidence (unintelligible)…
GOLDSTEIN: That's Dr. Val Randall at the University of Bradford in England. She is one of a few people doing research on hormones and hair. She says it's difficult to figure out what's going on because this kind of change doesn't happen very often. But she did point out that this change is possible because hair is always replacing itself.
Dr. RANDALL: The hair that you've on your head, age 10, is not the hair you have on your head age two, and it's not the hair that you have on your head age 50.
GOLDSTEIN: So if your follicles change shape for some reason, then your new hair will be a different shape too. I made at least a dozen more calls, but I couldn't find anyone who knew why this would happen. But what I did find is that there's an entire industry working on it.
Dr. ZOE DRAELOS (Dermatologist): There are multi-million dollar research projects going on looking at ways of changing hair shape, because this would be a billion-dollar business.
GOLDSTEIN: Zoe Draelos is a dermatologist in North Carolina. Some of her research is supported by the cosmetics industry. They're looking beyond perms and irons. For them, figuring out a simple way to turn hair straight or curly would be a gold mine.
Dr. DRAELOS: Wouldn't it be great if you took a pill and your hair turned curly? I mean, can you imagine how that would revolutionize hair care? And then you could take another pill and you could reverse it the next day.
GOLSTEIN: Until then, I think I'll stick with my curls.
Jessica Goldstein, NPR News.
MONTAGNE: And there's more. We'll have experts on hand at noon Eastern time today to answer you hair care questions in a live Web chat. That's at NPR.org. Hey, I'm going.