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Wavelength of Red Light

Remember the last time you saw a rainbow? … Peeking through the clouds after a rainstorm, they’re a pretty sight.

At that moment, you weren’t just admiring the picturesque sky; you were looking at the visible light spectrum – all the colors we can see with the human eye, each with varying wavelengths and each having a different effect on our health.

Fortunately, medicine is finally catching on to the healing potential of the various wavelengths. Studies show that red light (at the end of the visible spectrum) can provide significant benefits for both our mental and physical wellbeing.

What is red light?

We’re all used to breaking out the suntan lotion when the warm weather comes – protecting ourselves against dangerous UVA rays that burn, damage, and age the skin. But not all light is harmful.

There are various shades along the visible light spectrum – blue, green, white, red – and they all penetrate our skin at different depths, affecting what’s going on below the skin’s surface and stimulating activity at a deeper level.

Red light occupies the ‘therapeutic window‘ where light emits at a wavelength that will work on our cells without causing damage. This window begins at around 600 nanometers (nm) and extends past 1200nm, where it becomes non-visible infrared light.

Long-wavelength red light

The human eye can see light with wavelengths between 380nm and 700nm.

Violet has the shortest wavelength of 380nm, while red light falls at the end of the spectrum, with longer wavelengths of 630nm to 700nm. Go beyond 700nm and you won’t see the red, but you can still feel the energy from those longer wavelengths (known as infrared) in the form of heat.

What is red light therapy?

Red light therapy involves using red light to treat certain health issues. 

Exposing our bodies to red light allows the longer wavelength rays to penetrate the skin and activate our cells – to heal, restore, and repair. 

It works by targeting our mitochondria, the ‘control center’ of our cells, which give the cells the energy they need to perform their biological functions. 

When mitochondria receive a dose of red light, they encourage the cells to produce more energy – energy used to repair damage, promote new growth, and/or improve their function.

Red light therapy goes by several names; you might also see it referred to as:

  • Photobiomodulation
  • Low-level Light Therapy (LLLT)
  • LED treatment
  • Cold laser therapy
  • Biostimulation

Red Light – Longer wavelengths, better health

The potential of red light was first discovered in the 1990s when biologists used red-light emitting LED lights to grow plants in space. 

Noticing that the plants responded extremely well to the red light (with the longer wavelengths stimulating photosynthesis and causing rapid but healthy growth), scientists began to wonder if they would have a similarly rejuvenating effect on astronauts, who faced many health challenges thanks to prolonged periods of weightlessness.

NASA began photobiomodulation trials, known as WARP (Warfighter Accelerated Recovery by Photobiomodulation), and the results were encouraging. They found that red light could provide relief for exhausted and depleted astronauts, treating their arthritis, muscle spasms, and stiffness, as well as increasing blood circulation.

Armed with this knowledge, NASA began expanding their use of red light therapy from astronauts to military applications for soldiers on the frontlines.

What can red light therapy be used for?

Fuelled by the buzz at NASA, red light treatments began attracting attention and now show promising results in clinical studies. It’s also been embraced by the alternative health community, where many appreciate the natural aspect of this therapy and how it gently activates the body’s own self-healing functions rather than relying on medications or surgical intervention.

NASA’s WARP technology uses wavelengths around 670nm, but science is now exploring the benefits of the entire red-light range (630nm to 700nm). In these wavelengths, three major effects are seen:

  1. Anti-inflammatory action
  2. Analgesic (pain relieving)
  3. Healing and repair of wounds

All three have big implications for our health, so let’s dive a little deeper…

611 – 650 nm 

Red light at the 611-650 wavelengths has been used to improve skin health, smoothing fine lines, rough spots, and wrinkles for a better complexion.

By stimulating collagen production in the skin cells, the longer-wavelengths “significantly” improved skin’s firmness, thickness, and appearance. It’s also been used to treat cellulite, stretch marks, acne, and other skin conditions such as psoriasis and rosacea.

Low-level light doesn’t just wake up the skin; it can also give our brain a boost, making us more focused and improving concentration. There’s evidence it can increase alertness and performance – night shift workers exposed to 630nm red light were more awake and did better in daily tasks than the control group in one study.

650nm – 700nm

Red light within this slightly higher range can:

  • Reduce inflammation and encourage wound healing by driving cell repair.
  • Encourage hair growth – at 655nm, red light can stimulate hair growth, mitigating the effects of hair loss and providing a potential treatment for follicle disorders such as alopecia, pattern baldness, and thinning.
  • Help you sleep better – One study showed red light with wavelengths of around 658nm improved sleep quality and helped combat insomnia. 
  • Smooth out scars and encourage skin repair – in one clinical trial, burn victims reported reduced scarring and less pain after treatment with 670nm LED light.

Infrared wavelengths

The terms infrared therapy and red light therapy are often used interchangeably, which gives rise to a lot of confusion! 

Simply put, infrared is the light outside the visible spectrum, above 700nm. You can’t see it, but you might be able to feel it and your cells certainly know it’s there.

Light at these longer wavelengths is also profoundly healing with the following benefits:

How to get your red light therapy

It’s now easier than ever to get your healing red light with many new technologies coming into the market. 

You can visit a salon for a relaxing and rejuvenating red light sauna that lets you sweat away toxins while getting a good dose of red light on large areas of skin. These are great for mood disorders such as depression, sleep issues (like insomnia), and fending off sickness by giving your immune system a boost.

If a salon’s not your thing, you can combine a workout with red light treatment by heading to the gym. More and more fitness centers offer red light therapy for skincare, muscle aches and pains, and joint stiffness or soreness. 

Planet Fitness, for example, now offers the Total Body Enhancement machine (also known as the Beauty Angel). This stand-up red light chamber resembles a tanning booth and allows users to get exposure to red light in a private, safe environment that provides whole-body healing.

If you’d rather get your therapy in the comfort of your own home, check out the many handheld or portable devices available. These include:

Devices like these allow you to direct your own therapy – deciding when and where to get your treatment. 

Easy to use and convenient, you can soak up some rays as part of your energizing morning routine, sneak in a session at lunch to give you a lift, or take time before bed to relax and soothe your system.

In summary

Only you (and hopefully your doctor) know what’s right for you and your body. Red light therapy is a non-invasive and natural solution for all kinds of health issues, but for targeted treatment, it’s always a good idea to do your research and know exactly what you’re looking for.

Different wavelengths can have different effects, so when using devices, be sure to pick the best option for your health goals. Read and follow all instructions carefully and keep a consistent schedule to maximize results.

Catherine Morris is a freelance content writer and award-winning journalist. Originally from Northern Ireland, she's now based in Canada where she writes about health, wellness, travel, the environment and anything else that sparks her curiosity.


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