How Stress, Age And Genetics Turn Hair Gray : Short Wave Why does hair turn gray? Stress? Age? Genetics? We turn to dermatologist Dr. Jenna Lester for answers.

Micro Wave: Why Hair Turns Gray

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BRIT HANSON, BYLINE: Hey, y'all. Brit Hanson, SHORT WAVE producer, here. Today, I'm teaming up with a familiar voice, NPR correspondent Rhitu Chatterjee, to bring you our latest microwave. Hi, Rhitu.


Hey, Brit.

HANSON: So excited that you're here, Rhitu.


HANSON: You're going to be with us occasionally over these next few weeks, hosting here and there. And we couldn't be more pumped. Welcome to the show.

CHATTERJEE: Thank you. And I am so thrilled. You know, just between you and me, Brit, SHORT WAVE is my favorite podcast.


CHATTERJEE: So I'm extra delighted to be here.

HANSON: Oh, my God. I'm so happy to hear that. This is going to be fun.


HANSON: OK. So, Rhitu, I don't want to be intrusive or anything. I know I'm scaring you, probably, but I'd really love for folks to get to know you a bit. So can I ask you a personal question?

CHATTERJEE: Well, do I really have a choice here? OK, just kidding, just kidding (Laughter).

HANSON: You do, you do. Consent, consent (laughter).

CHATTERJEE: Ask away, ask away.

HANSON: OK. Do you happen to have any gray hair?

CHATTERJEE: I definitely have a couple. And to be honest, after this incredibly stressful last year, when I also became a mom, so even more stress...

HANSON: (Laughter). Yeah.

CHATTERJEE: ...I actually may have more.

HANSON: Me, too, Rhitu. I'm not a mom (laughter), but I actually - I have a lot of gray hair, and I think probably from what it sounds like, more than you even. And I'm noticing more all the time, like you, especially after this pandemic here. And it's actually gotten me really curious. Like, why does hair turn gray? Is it stress?


HANSON: Is it age? Is it genetics? I need some answers.

CHATTERJEE: I do as well.

HANSON: (Laughter).

CHATTERJEE: So today on the show, Why Hair Turns Gray. We ask an expert and find out why some of us get grayer sooner than others.

HANSON: And some listener mail about a recent episode that you, Rhitu, actually brought to SHORT WAVE.

CHATTERJEE: Oh, that's exciting. Can't wait for that. OK. You're listening to SHORT WAVE, the daily science podcast from NPR.


CHATTERJEE: OK, Brit, we are talking about why hair turns gray. So who'd you talk to?

HANSON: I called Dr. Jenna Lester. She's a dermatologist and professor in the Department of Dermatology at the University of California, San Francisco.

CHATTERJEE: Wait. Dermatologists...

HANSON: (Laughter).

CHATTERJEE: ...Treat hair as well?

HANSON: You know what? I didn't know that either, Rhitu. But yes, it turns out that many dermatologists actually treat anything related to skin, nails, and hair. And Jenna's been on the show before in an episode about how dermatology is evolving to better serve patients of color.

CHATTERJEE: I remember that. It was a fantastic episode.

HANSON: Yeah. It was so good. OK. So, Rhitu, much like I did with you, I opened my conversation with Jenna in, let's say, a very professional manner.

This is a hard-hitting and intrusive question, but, Jenna, do you have gray hair?


JENNA LESTER: I do not have any gray hairs yet. Occasionally, I'll find one. And the most recent one that I found fell out not too long ago. And interestingly, two did not grow back in its place.

CHATTERJEE: Lucky her, Brit.

HANSON: (Laughter).

CHATTERJEE: And you know what my mom used to tell me when I was little, and this is around the time her head started to turn gray first? She said, well, if you have a gray hair and it falls off or you pluck it out, the rest of your hair is going to turn gray faster.

HANSON: Oh, my gosh (laughter).

CHATTERJEE: Clearly an old superstitious tale back in India.

HANSON: Oh, that's really funny. Well, Rhitu, guess what Jenna told me? She told me that hair doesn't actually turn gray.

LESTER: Yes. Like, if you have a brown hair or blondish hair on your head, tomorrow, it's not going to be gray. It's the new hair that's coming in that will either have pigment or not have pigment.

CHATTERJEE: I did not know that. So once a hair starts to grow, it stays the same color.

HANSON: Yeah, exactly. And to understand why some hairs grow in gray while others don't, you have to understand something called melanocytes.

LESTER: Hair is the color that it is because of the melanocytes or pigment-producing cells that are concentrated around the hair follicle that give it color.

HANSON: Now, every hair follicle has these cells - melanocytes. And if for some reason they stop producing pigment, that's when you get a gray hair.

LESTER: So hair turns gray or white in any situation where those cells aren't functioning in the way that they should, so not making pigment.

CHATTERJEE: OK. I get it. So gray hairs are actually just hairs without pigment.

HANSON: Mm hmm.

CHATTERJEE: But why would melanocytes stop producing pigment?

HANSON: Well, Jenna says that there's a lot of reasons, but the most straightforward one is aging, which is probably, like, not a surprise to those of us over 30.

LESTER: So, over time, those cells just stop making as much pigment as they had been before or any. But there are also certain inflammatory conditions where hair can also turn white like vitiligo. For example, vitiligo is when your skin loses its pigment. So in addition to your skin being - losing its pigment, your hair does as well.

CHATTERJEE: That's fascinating. OK. But tell me, why do some people - you, for example - get gray hair sooner than others, say, like me?

HANSON: Well, Jenna says that there are a number of factors that determine when people start graying. But one of the big ones is genetics, whether or not people in your family start graying early in their lives. And then, Jenna says...

LESTER: Some people think sun exposure can damage their melanocytes more or less. And hormones also play into it as well. So the reason why it happens is multifactorial. So it's hard to zero in on, like, one specific thing that might cause one person to gray sooner than another.

HANSON: So, you know, it's basically different for everyone.

CHATTERJEE: OK. So there's genes. There could be sun exposure, inflammation, hormones. All of these play a role, I get that. But I'm curious, Brit, what about stress? Like, is it actually true that the stress of this past year made my or your hair grayer?

HANSON: Yeah, I wondered about that, too. And it turns out that this has been widely debated. Just last year, there was a mouse study published in the journal Nature that found that acute stress can cause graying by damaging melanocytes.

CHATTERJEE: And those are the pigment-producing cells that we learned about earlier.

HANSON: Yes, exactly. And, you know, of course, this is a study in mice, not humans.


HANSON: But Jenna says it's still a pretty big deal.

LESTER: So I think it's a proof of concept that stress does cause hair graying.

CHATTERJEE: All right. That means I keep telling people that...

HANSON: (Laughter).

CHATTERJEE: ...The pandemic has grayed me more.

HANSON: Yes. You can say, you know, and there's some evidence, at least in mice, so (laughter).


HANSON: OK. So, Rhitu, one more thing before we move on to listener mail, because I just haven't been able to let it go. I asked Jenna if she has any thoughts on gray hair, you know, in general as a dermatologist because, I mean, to be honest, I, myself, have some really mixed feelings about mine. And I think part of that is because there's some really strong societal messaging, especially for those of us who have been socialized female.


HANSON: And I really, really loved her perspective on this.

LESTER: I am a dermatologist, but I'm also the daughter of a geriatrician.


LESTER: And my mom is all about successful aging. So I don't think gray hair is something to run from. I think of it as an achievement for some people too because, you know, depending on what your family structure is like, you may be the first one in your family to reach the age you've reached, so some people are really proud of their grays. I think there's a lot of different ways to look at it and frame it. And maybe if you're feeling stressed about it, looking at it outside of the cosmetic lens can be helpful.

CHATTERJEE: Oh, gosh, Brit. I'm so glad you asked her this. And I love the way Jenna frames this because...

HANSON: Right?

CHATTERJEE: ...You know, I'm from India. And in my culture, gray hair as a sign of age, it gets you respect because it's a sign of you having lived longer, have had more life experiences. So I absolutely agree with her.

HANSON: Yeah, right? I just need to reframe these grays as wisdom (laughter).

CHATTERJEE: Yes, you do.

HANSON: OK. I'm going to work on them. I'm going to work on it. OK. So, Rhitu, are you ready now for some listener mail?

CHATTERJEE: Absolutely. I love this part of the episode.

HANSON: Yes, me too, Rhitu. And I picked out some listener mail, especially for you, related to when you were last on the show, which was really poignant.

CHATTERJEE: Thanks, Brit. I think you're talking about the episode where I talked to Emily about how to reach out when someone you know might be at risk of suicide.

HANSON: Yeah. Rhitu, that was a really powerful episode. And we got a lot of listener mail. This email came from a listener who's a social worker. I just want to thank you for the very important episode on suicide. Our small community has been hit hard. Please remember to revisit this topic. I think discussing biochemistry and what our brains are doing when we feel sad or low mood would be extremely interesting. Sometimes when I explain serotonin to my clients, it feels like less of a moral feeling and more of a biochemical response. Thank you again for all of the work you put into connecting people to science. I appreciate you.

CHATTERJEE: And we appreciate you for writing to us. Our goal with that episode was to both help remove the stigma around suicide and also to empower people with practical information that they can use to help someone who might be struggling.


CHATTERJEE: So it means a lot to know that it resonated with our listeners.

HANSON: Yeah, absolutely. And thank you so much to all of you out there who have written in. We love hearing from you. So if you've got a note to share, email us at

CHATTERJEE: This episode was produced and reported by the wonderful Brit Hanson...

HANSON: ...Fact-checked by Rasha Aridi, and edited by Viet Le and Gisele Grayson.

CHATTERJEE: I'm Rhitu Chatterjee. Thank you for listening to SHORT WAVE from NPR.

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