Red-light masks: can they really slow ageing?

Summary

Science Weekly – "Do red-light masks really keep you looking young?"

Date: May 26, 2026
Host: Ian Sample
Guests: Maddie (Science Journalist), Dr. Jonathan Kentley (Consultant Dermatologist)

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Overview

This episode investigates the science behind the booming popularity of red light therapy masks, asking whether claims about their anti-aging and skin health benefits stand up to scrutiny. Host Ian Sample and colleague Maddie discuss the biological basis for red light therapy, its history, studies on effectiveness, and advice on whether to spend money on the latest at-home devices. With expert insights from Dr. Jonathan Kentley, the discussion also explores possible future medical applications for red light.

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What Is Red Light Therapy?

[03:15] Maddie

• Red light therapy involves exposing skin to red light waves, believed to yield health or aesthetic benefits.
• Red light sits at the long-wavelength end of the visible spectrum, just before infrared, enabling it to penetrate the skin by millimeters and potentially a few centimeters.
• These properties have led to speculation about health impacts: “It’s getting into our bodies and it's interacting with us in supposedly a beneficial way.” [03:15]

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Origins and Early Discoveries

[04:13] Maddie & Dr. Jonathan Kentley

• The idea is rooted in “phototherapy” (now called photobiomodulation), a decades-old concept of using light to treat conditions.
• The story starts in the late 1960s when scientists testing lasers on mice for cancer found that the mice’s hair regrew faster under low-energy ruby lasers.
  • Quote: “They’d shave the mouse’s stomach and they basically irradiated it with a low energy ruby laser...they actually regrew their hair much quicker than the other mice.” – Dr. Jonathan Kentley [05:10]
• NASA also noticed faster wound healing among scientists working under red light while studying plant growth in space.

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The Science: How (Supposedly) Red Light Works

[06:07] Maddie & Dr. Jonathan Kentley

• Red light is absorbed by cell molecules called chromophores (notably, cytochrome C oxidase) in the mitochondria – the cell’s energy factory.
  • Quote: “...Increases the metabolism of the cell. So you’re producing more ATP, which is kind of like the gasoline or the fuel that your cell needs to run on...things like producing new collagen, reduction in inflammatory chemicals in the skin, amongst other things...” – Dr. Jonathan Kentley [06:22]
• The theory: Red light boosts ATP (cellular energy), theoretically enabling cells to function more youthfully and repair themselves better.

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Claims & Evidence: Do the Masks Work?

[07:26] Maddie, Ian Sample & Dr. Jonathan Kentley

• Mask manufacturers claim red light prompts the skin to produce more collagen, aiming to fight sagging, thinning, and wrinkles.
  • Quote: “They are marketed as a way to stay looking younger for longer, using these LEDs...to produce this red light.” – Maddie [07:26]
• Laboratory studies show fibroblasts (collagen-producing cells) exposed to red light make more collagen – but this is in petri dishes, not through layers of human skin.
• Human studies mainly rely on subjective assessments (wrinkling, hydration, radiance), with no direct quantification of collagen increase.
  • Quote: “...There’s no real measure of the amount of collagen that’s going to be increased. And obviously it’s going to be very, very much from mask to mask and person to person.” – Dr. Jonathan Kentley [08:57]
• Summary phrase: “Promising. But needs more evidence.” [09:40 & 09:50]

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Other Skin Concerns: Acne, Skin Tone, and Hair Loss

[09:50] Maddie & Dr. Jonathan Kentley

• Acne: Some studies show red light therapy may help, even outperforming topical retinoids and oral antibiotics in reducing spots – but more trials are needed.
• Hair loss: A 2025 review found red light therapy “safe and effective” for androgenic alopecia (pattern hair loss in men and women).
  • Quote: “A review from last year from multiple specialists concluded that red light therapy was safe and effective for androgenic alopecia...” – Maddie [10:30]

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Should You Buy a Red Light Mask?

[11:19] Ian Sample, Maddie, Dr. Jonathan Kentley

• No one knows the “correct” dose, intensity, or duration – huge variations in studies (e.g. 2–120 joules/cm², duration, and frequency).
• Commercial devices’ effectiveness varies greatly, and there are no standards.
• Expert advice:
  • “My general advice that I tend to give to people is if you have the money and you want to do something that may help, certainly feel free to invest in a mask. But don’t go into it thinking that it’s going to be a life changing outcome...Anyone who’s telling you they’re going to obliterate all your wrinkles with an at-home cream or an at-home device, really, they’re lying to you.” – Dr. Jonathan Kentley [11:53]

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Beyond Aesthetics: Medical Potential

[13:24] Maddie

• Exciting medical research ongoing, inspired by the idea of red light accelerating healing (e.g. NASA’s wound healing observation).
• Age-related macular degeneration (vision loss): Trials underway to see if red light can preserve retinal cell health.
• Other areas of interest: Brain injuries, Alzheimer’s, muscle repair, osteoarthritis, pain, neuropathy – all with “exciting signals,” but clinical application is far off.
• Quote: “...many years away from getting into a tank and feeling better.” – Maddie [15:05]

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Memorable Moments & Notable Quotes

• [01:55] Ian Sample’s opening description: “Sitting in the dark is a figure you don’t quite recognize...White mask over their face, an unearthly red glow coming from below...It sounds like something from a horror movie, but it’s actually the latest trend...”
• [09:50] Maddie: “Promising. But needs more evidence. I’m going to get us T-shirts printed with that.”
• [15:05] Maddie: “Isn’t that a great sci-fi dream? That we can kind of get into a tank and be rejuvenated and our injuries are gone and we look lovely and young? The science is very far away from that.”

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Key Timestamps

• [03:15] – What is red light therapy?
• [05:10] – Early discovery & mouse hair regrowth
• [06:22] – How red light is believed to work (cellular mechanisms)
• [07:26] – Claims about collagen and anti-aging
• [08:57] – Lab tests vs. real-world application
• [09:50] – Acne, skin conditions, “Promising. But needs more evidence.”
• [10:30] – Hair loss: evidence in men and women
• [11:53] – Advice on if you should buy a mask
• [13:34] – Red light’s medical potential
• [15:05] – Sci-fi visions vs. scientific reality

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Tone & Language

• Lively, conversational, and skeptical: a blend of curiosity, excitement about science, and caution about consumer hype.
• Regularly returns to the theme of scientific rigor vs. marketing claims.

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Conclusions

• There is some scientific basis for red light’s effects on cells, but proof for anti-aging at-home masks is limited and not robust.
• For hair loss and acne, red light therapy appears modestly effective in some studies, but large, standardised human trials are lacking.
• Don’t expect miracle results, and be wary of overblown marketing promises.
• Exciting medical uses may emerge in the future, but practical, everyday rejuvenation is still science fiction.
• Best advice for healthy skin: regular sunscreen and outdoor activity—“that’s free.” [15:05]

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Transcript

[Ian Sample]

This is the guardian.

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[Ian Sample]

Imagine coming home. You're expecting to see your partner or your mum or dad. But sitting in the dark is a figure you don't quite recognize. White mask over their face, an unearthly red glow coming from below. Dark holes where their mouth and eyes should be. It sounds like something from a horror movie, but it's actually the latest trend in our age old quest to look younger for longer. Red light therapy has been around for decades, but until recently was only available in expensive dermatology clinics. That's all changing thanks to an explosion in the range of devices you can use at home. So today, what's the science behind red light therapy? Do these at home devices actually do anything? From the Guardian I'm Ian Sample and this is Science Weekly. Maddie Red light therapy masks have become all the rage. I basically had to run from someone in John Lewis the other day who was attempting to get me to try one on. So look, to start off, what is red light therapy?

[Maddie]

So this is the idea that shining red light on yourself is going to have some kind of health or aesthetic benefit. So let's think about the electromagnetic spectrum, starting with uv, which is short wavelengths. Then you go into the visible spectrum and you're going to have the short wavelengths of visible light that's blue and purple. And then as the wavelengths get longer, think of the rainbow, you go yellow, orange, red. So red has the longest wavelengths that we can see. And after that you go into infrared and those long wavelengths allow the light to penetrate our skin millimeters and perhaps even a few centimeters deep. And so it's getting into our bodies and it's interacting with us in supposedly a beneficial way.

[Ian Sample]

And where did this idea come from that shining red light on yourself would actually have some kind of benefit?

[Maddie]

The concept behind what is sometimes called phototherapy or now photobiomodulation, has actually been around for quite a long time. This idea that shining different wavelengths of light could treat potentially different conditions. And there is some logic behind it. You know, you think about how we make vitamin D, for example. Light shines on us, we produce vitamin D. But look for this research on red light therapy, I got in touch with Dr. Jonathan Kentley, he's a consultant dermatologist who works for the NHS and in a private practice. And I asked him the same thing. When did red light therapy begin to take off, really? And like all the very best scientific discoveries, Ian, it happened by accident. In the late 60s, a scientist was shining lasers on mice, as they do, and it was to see if it would cause cancer, but in fact it did something else.

[Dr. Jonathan Kentley]

As part of it. They'd shave the mouse's stomach and they basically irradiated it with a low energy ruby laser. But they observed that actually in the mice that they had treated with the laser, they actually regrew their hair much quicker than the other mice. So that's really where the concept of what at the time was called low level laser therapy came about. And since then it's been built on and built on.

[Maddie]

So, yes, slightly hairier mice. But another accidental example of this was in the when NASA scientists researching how to grow plants in space noticed that scratches on their hands tended to heal up quicker when they worked under red light. And I don't know why, Ian, NASA scientists are so scratched up, but that's another mystery that needs solving.

[Ian Sample]

So it sounds like there is some science behind this, or at least some claimed science behind this. What is going on there? What are they thinking?

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[Ian Sample]

What are they saying are the mechanisms?

[Maddie]

The theory goes like this. The red light penetrates the skin and it's absorbed by cells. In those cells are chromophores these are molecules that absorb light. And one of these is called cytochrome C oxidase.

[Dr. Jonathan Kentley]

There's a little enzyme called cyclooxygenase that lives in the mitochondria, which is kind of like the energy factory of your cell. And it absorbs the energy from the light and it increases the metabolism of the cell. So you're producing more ATP, which is kind of like the gasoline or the fuel that your cell needs to run on. And because of that, you get a lot of downstream effects. So things like producing new collagen, reduction in inflammatory chemicals in the skin, amongst other things, like forming new blood vessels.

[Ian Sample]

Right. So the theory is that these molecules absorb the red light and that then boosts production of ATP, which is basically fuel for cells. And as we get older, our cells make less ATP, and that can cause inflammation, but also the cells have less energy to do their jobs. So the principle is that maybe red light could kind of rejuvenate cells again. And, like, does that translate into rejuvenating us?

[Maddie]

That's a really good question, because that's ultimately the claim that these masks and red light therapy products are making. They are attempting to make use of this biological effect. You know, they're marketed as a way to stay looking younger for longer, using these LEDs that they have in them to produce this red light. Now, one change to our skin as we get older is that it produces less collagen, and that makes it saggier, thinner, and more wrinkled.

[Dr. Jonathan Kentley]

We're born with large amount of collagen and to some extent, elastin in our skin, which gives it elasticity, elastic, to spring back to its original place. And as we get older, the balance between production of new collagen and breakdown of old collagen gets tipped. So with sort of recurrent movements of the face, those lines that would be there, what we call dynamic lines, when you're moving, become lines at rest.

[Maddie]

There are other factors that affect our skin as we age. So think sun exposure, pollution, smoking and drinking. Maybe you lose a bit of the fat in your face, which would otherwise kind of plump it up and maybe fill out some of those wrinkles. And maybe you get a bit of an uneven skin tone because, you know, you spend years out in the sunshine. But the principle behind all this is that these masks are supposed to stimulate our cells to make more collagen. Does it work? Well, Jonathan told me they had done tests in the lab, so they put

[Dr. Jonathan Kentley]

a fibroblast, which is the cell that makes collagen, into a petri dish and they shine a light on it, and that cell produces more collagen, which is great. But you're just shining a light on one single cell. You have to think, where in the skin is that cell? If you're shining LED light on the skin, you have to get through a few millimeters of skin and epidermis to really get the energy where it needs to be. So the studies, particularly for anti aging on the masks, tend to be centered around clinicians doing assessments of wrinkling and hydration and radiance. There are to some extent subjective. So there's no real measure of the amount of collagen that's going to be increased. And obviously it's going to be very, very much from mask to mask and person to person.

[Ian Sample]

Right, So a classic Science Weekly phrase here, promising. Needs more evidence. What about other skin conditions like acne or uneven skin tones?

[Maddie]

Ian, I'm going to get us T shirts printed with the phrase promising. But needs more evidence because I'm about to say it again. There have been studies looking at the impact on acne and uneven skin tones or even skin conditions like psoriasis. And red light therapy does seem to help for acne. For example, one study found that it reduced spots more than a topical retinoid and an oral antibiotic. But I think more studies are needed, more trials are needed.

[Ian Sample]

And how about these other aesthetic benefits? If those mice got nice and hairy, could could red light do the same for people with hair loss?

[Maddie]

I do think it's a mainstay experience of science journalists that we get really excited when we see a headline and then we sort of read on and that disappointed feeling when we see that it's actually just research in mice because humans are, of course, very different from mice. But saying that actually a review from last year from multiple specialists concluded that red light therapy was safe and effective for androgenic alopecia, which is pattern hair loss in men. That's the classic kind of hair loss on the crown or at the front. And for women, it's the sort of general thinning that you might experience. And another small trial using red light therapy did appear to have some benefits in terms of reducing hair loss and improving hair thickness.

[Ian Sample]

So with all this considered, should we be buying red light therapy masks?

[Maddie]

Well, I hesitate to tell people how to spend their money if it was me. No, because in my opinion, having looked at the evidence, there is a little bit. But there's so few good trials with lots of participants. And it's really not clear what the right dose is or if that's what you're going to get from a commercial product. There's no standard, there's no kind of set thing. But I did ask Jonathan about this.

[Dr. Jonathan Kentley]

I don't think anyone has really decided what the parameters are. And the parameters is when we think about how far away from the skin, how strong the energy is and how long you use it for. And if you look at the studies, the figures that they quote vary hugely. So if you look at fluence, which really represents how strong the light is that's going into the skin, that ranges in studies from 2 joules per centimeter to 120 joules per centimeter. And some of these will be every day for 10 minutes, some will be three times a week. So it's very difficult to compare like to like. My general advice that I tend to give to people is if you have the money and you want to do something that may help, certainly feel free to invest in a mask. But don't go into it thinking that it's going to be a life changing outcome that you're going to see in your skin. Anyone who's telling you they're going to obliterate all your wrinkles with an at home cream or an at home device, really, they're lying to you.

[Ian Sample]

Coming up, what other health conditions might red light therapy show promise for in the future?

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[Ian Sample]

Maddie. Beyond aesthetics, it seems like the principle behind red light therapy could be useful for medical applications. Is that being explored?

[Maddie]

It is. And I think this is where the science actually gets really, really interesting. So if you go back to that NASA example where they found scientists wounds seem to heal faster if they'd been under red light, it gives this hint that red light therapy really could be used medically. Almost like something from a superhero film. They get beaten up and then they go into their pod and their wounds heal. We can't go there yet, but one place that's being studied is for age related macular degeneration. So this is a common sort of vision loss that you get as you get older. And it could slow this down by keeping retinal cells in the back of the eye healthier for longer. And that's a question that's being Investigated in trials with some early, potentially promising results.

[Ian Sample]

And what other areas are scientists interested in?

[Maddie]

Well, as you can imagine, there are loads of areas that scientists think maybe this could have an application. So they've looked at it for brain injuries like strokes, there's some interest in it for Alzheimer's, there's interest in it for other injuries. Again, that NASA example, muscle repair. So you think, could it help athletes? They are looking at it for osteoarthritis and also for things like pain and neuropathy.

[Ian Sample]

It does sound promising. So are we all going to end up going for like these weekly red light immersion sessions in the future?

[Maddie]

Isn't that a great sci fi dream? That we can kind of get into a tank and be rejuvenated and our injuries are gone and we look lovely and young? The science is very far away from that. You know, there are these exciting signals with different conditions, but yeah, many years away from getting into a tank and feeling better. I mean, when you look at the aesthetic stuff, you have to ask yourself, how much difference is this going to make in comparison to the stuff we really do know makes a difference? Like when you go outside wearing sunscreen and on that point we spend a lot of our time indoors, most of us do. And maybe actually what we could do is just put on some sunscreen and go outside. There's quite a lot of light outside and that's free.

[Ian Sample]

Radical idea. Thanks again to Maddy. And that's all from us. This episode was produced by Ellie Sands. The sound design was by Josh and Chana and. And the executive producer was Ellie Burey. We'll be back on Thursday. See you then.

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[Maddie]

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