Wellness·4 min read

How Does Light Affect Your Health? We Found Out

Red light therapy
November 28, 2023

Blue light has long been considered the "bad" light when it comes to your sleep, but what if that’s not exactly true? And what about all those claims about red light being an anti-aging skin hack on social media? We called up some experts to bring us out of the dark.

How does light impact your health? 

Let's bring it back to high school physics: Light is a form of electromagnetic radiation that travels as waves of energy. Red and blue light are not on the same wavelength. In fact, they’re on opposite sides of the visible light spectrum (the types of light we can see), which ranges from shorter wavelengths that carry more energy (like blue light) to longer and lower-energy wavelengths (like red light). Visible light is just a small slice of the larger electromagnetic spectrum that includes many different wavelengths that our eyes can't detect (including radio waves used for communication, ultraviolet rays from the sun, and infrared light, which emits heat). 

How light affects your body depends on the size of the wavelengths and the energy they carry. Longer ones “penetrate deeper into the skin, and this affects what structures within the skin they can reach,” says Tiffany Libby, MD, a dermatologist and Mohs surgeon at Brown Dermatology. Shorter wavelengths carry more energy, which may make them more likely to damage cells. The amount of light and what body parts are exposed also matter. 

Does red light therapy work?

Sunlight and fires produce red light — but the source for red light therapy is artificial lighting (usually through a device). Red light can penetrate the first and second layers of skin and stimulate skin cells, according to Libby. She says this may help boost collagen production, reduce inflammation, and help wounds heal faster. That’s why it’s sometimes used to help treat conditions like psoriasis, acne, and hair loss and improve the look of stretch marks, scars, wrinkles, and more.

Some studies support these uses. However, skin damage is possible when using red light therapy. And Nazanin Saedi, MD, a cosmetic dermatologist, says there still aren’t standardized treatment protocols for red light therapy, and more research is needed to understand how effective it is. 

How blue light affects your health

The sun is a major source of it, but artificial lights and electronic devices also emit blue light. During the daytime, blue light “synchronizes the [body] clock” and “promotes alertness,” explains Mariana Figueiro, PhD, director of the Light and Health Research Center at Mount Sinai. It does this by passing through the eye to reach cells that help control your circadian rhythm. The presence of blue light signals those cells to suppress melatonin production

Some studies on animals have found that high levels of blue light exposure could damage eyes over time. That might sound concerning, considering how often we all have a screen in front of us. The good news is, current research suggests that the amount of blue light they emit isn’t enough to do real harm — especially considering that the sun gives off more blue light by a longshot.

Unlock the health benefits of light 

Here's how you can get the most benefits from... 

  • Blue light: The best source is the sun, so getting sunlight in the morning (ideally soon after waking up) for at least 30 to 60 minutes can keep your biological clock properly synced. Filtered sunlight (like through sunglasses) won’t have the same effect, so do your best to get direct rays — and don’t forget your sunscreen. Some experts also say to minimize exposure to blue light a couple of hours before bedtime so it doesn't interrupt your sleep. 

  • Red light: If you’re interested in using red light therapy devices for wrinkles or other skin concerns, Saedi suggests managing your expectations. “It is not going to benefit people with severe wrinkles,” she says. Plus, you’ll likely need numerous treatments to see the effects, she adds. In-office red light therapy will probably be more impactful than using at-home devices. 


While different types of light can come with health benefits, there's still a lot we don't know about red and blue light treatments — and how effective or risky they can be for your skin, eyes, sleep, and overall health.

This content is for informational and educational purposes only. It does not constitute a medical opinion, medical advice, or diagnosis or treatment of any particular condition. 

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