Infrared vs red light: what's the difference?

Red and infrared light are not the same thing. They are two different kinds of light that sit beside each other on the light spectrum, however have very different properties, and are used for different purposes.
 
Light therapy is often categorised according to colours. This is because each colour of light has a different wavelength. For example, blue light has a wavelength between 450-495 nanometres (nm), while red light therapy has a wavelength around 600-700 nm. This means that red light wavelengths are longer than blue light. Infrared light has wavelengths even longer: between 750- 1000000 nm (which is 1 millimetre). It's important to know that red and infrared light exist at the opposite end of the spectrum to harmful UV light. UV light has far shorter wavelengths (100-400 nm), which are potentially ionizing, meaning that UV light can cause skin cancers. Red and infrared light have a much higher safety profile, and non-ionizing, meaning that they do not cause skin cancer. 
 
The main difference between red and infrared light is that we can see red light, whereas we cannot see infrared light. Infrared red light is invisible to the human eye. You will only be able to see infrared light if you look through special kinds of infrared cameras.
 
Different wavelengths treat different things. Longer wavelengths (infrared light) penetrate more deeply, and so if you are looking to treat pain and inflammation, you would use an infrared light device (1). Excellent treatment guidelines exist for the use of 904 nm infrared laser in particular, thanks to WALT (the World Association of Laser Therapy). Remember that, because it's infrared light, when you turn these devices on, you will not see the light! Nevertheless, it's emitting powerful light energy, so we don't recommend shining it in your eyes. 
 
If you are looking to promote tissue repair of superficial issues, such as skin conditions, you may want to use a red light device, such as a 635 nm device. Red light is particularly useful for promoting blood flow to encourage superficial tissue repair (2). However it will not penetrate as deeply as infrared light, meaning it won't be effective for deeper issues (1). This is also why, if you're looking for a helmet to treat the brain, you need a device that uses both infrared and red light: studies show that red light doesn't penetrate through the skull, whereas infrared light can directly stimulate brain tissue (1, 3). 
 
The benefits of infrared light may include (1-5):
  1. Reducing pain by modulating nerves 
  2. Controlling excess inflammation 
  3. Penetrating deeply to treat arthritis, joint and disc problems 
  4. Modulating the gut microbiome
  5. Stimulating the gut-brain axis for treatment of conditions such as Parkinson's
  6. Nerve repair, such as in peripheral neuropathy 
  7. Reducing brain fog and improving mood, cognition and concentration
  8. Increasing energy at the cellular level 
  9. Reducing oxidative stress and stimulating the body's anti-oxidant capacity
  10. Improving lymphatic drainage by stimulating lymph vessels 
  11. Improving athletic performance and recovery 
 
As you can see, the benefits of infrared light therapy are vast. There is extensive research on infrared light therapy. But that's not to forget about red light completely; red light, between 600-700 nm, also has it's place, and we commonly recommend red light to customers. 
 
5 benefits of red light therapy may include (1-5):
  1. Improving blood flow and promoting circulation
  2. Stimulating keratinocytes, which promote skin health and repair
  3. Treating ulcers, wounds and skin autoimmune conditions (such as psoriasis, dermatitis and vitiligo)
  4. Reducing superficial nerve pain, such as in post-shingles pain and some kinds of peripheral neuropathy of the feet or hands
  5. Increasing collagen production by stimulating fibroblasts
As you can see, depending on what condition you are treating, and in what part of the body, you may decide to choose either red light or infrared light. For anything deep, you'll want infrared light, however for superficial issues, you may want red light.
 
Remember too that lasers and LEDs are not quite the same: an infrared sauna will not have the same effects as a handheld laser, for example. This is because LEDs use scattered, non-coherent light, which is often believed to mean within the industry that it doesn't penetrate as deeply as laser, which uses coherent, monochromatic light to maximise the depth of penetration. With a laser, you're also most likely holding the laser against the skin, to further increase the chance of penetration, and, if it's a SYMBYX device, following a very specific, research-backed protocol to ensure you get positive results. This is crucially important, as too much or too little light stimulus both offer diminishing returns. Yes, it is possible to over-stimulate your body with light! In some cases, this can make people feel worse, such as developing a worsening tremor, worsening sleep, or worsening brain fog, but for many people, it simply means that they feel nothing: they feel no worse, but they experience none of the benefits, either!
 
It's very difficult to know what kind of dosage you're getting with an infrared sauna, but with a handheld laser, you always know! This also helps our international team of clinicians help you, should you need it (remember you get full ongoing clinical support throughout your light therapy journey). 
 
If you're unsure which device is right for you, please email our team at info@symbyxbiome.com. One of our clinicians can help you choose the right device, and provide you with instructions to safely and effectively treat in the comfort of your own home. And remember, always choose a light therapy device that's ISO-compliant, meaning that it's gone through rigorous safety and compliance testing, and does what it says it does. As you can see, not all light is made equal, and when it comes to your health, you want quality and confidence!  
 
References:
 
1) Jagdeo JR, Adams LE, Brody NI, Siegel DM. Transcranial red and near infrared light transmission in a cadaveric model. PLoS One. 2012;7(10):e47460. doi: 10.1371/journal.pone.0047460. Epub 2012 Oct 15. PMID: 23077622; PMCID: PMC3471828.
2) Barbosa LS, Parisi JR, Viana L do C, Carneiro MB, Silva JRT da, Silva ML da, Dias Novaes R, Sousa de L. The photobiomodulation (658, 830 and 904nm) on wound healing in histomorphometric analysis. Fisioter mov. 2020;33:e003318.
3) Salehpour F, Sadigh-Eteghad S, Mahmoudi J, Kamari F, Cassano P, Hamblin MR (2023). Photobiomodulation for the Brain: Photobiomodulation Therapy in Neurology and Neuropsychiatry. Springer Charm. https://doi.org/10.1007/978-3-031-36231-6.
4) Tsai SR, Hamblin MR. Biological effects and medical applications of infrared radiation. J Photochem Photobiol B. 2017 May;170:197-207. doi: 10.1016/j.jphotobiol.2017.04.014. Epub 2017 Apr 13. 
5) Hamblin MR. Mechanisms and applications of the anti-inflammatory effects of photobiomodulation. AIMS Biophys. 2017;4(3):337-361.
6) Hamblin MR, Demidova TN. Mechanisms of low level light therapy. Proc. SPIE 6140, Mechanisms for Low-Light Therapy, 614001. 2006. 

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