What Are the Side Effects of Red Light Therapy?

New Updated Findings!

You may have heard about the many benefits of red light therapy. It’s not hyperbole; there are scores of studies supporting red light therapy as an effective treatment for a variety of issues, from pain relief, to skin rejuvenation, wound healing, and more (for a more comprehensive view of the benefits of red light therapy, check out our blog). That’s not the only thing that has experts more than intrigued by the treatment. One of the most important characteristics of red light therapy - an extremely rare one at that when it comes to any sort of therapeutic treatment - is that it is very safe to use for most people, and in fact, and there are no documented serious risks or side effects.

That said, while most people will only experience positive effects, there are some who might notice some mild side effects. Here are the most common.

From a Rouge customer: My husband and I have been using our Red Light Panel for about 4 weeks now and we both love it! It has made a huge difference on sore muscles and aching joints! I just ordered a second panel today, can’t wait for it to arrive!! Thanks Rouge

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Slight tightness and redness in the skin

Some people may experience temporary skin irritation in the area exposed to treatment. It may feel a bit like a sunburn. However, it’s important to note that this effect is not at all like a sunburn. First, sunburns are caused by ultraviolet light, which is known to damage the skin. These UV rays cause damage either by directly damaging DNA, which can lead to skin cancer, or by agitating molecules within the cell, causing reactive oxygen species to form.


Red and near-infrared light used in red light therapy, on the other hand, does not cause damage to the cell. Quite the contrary, in fact; red light therapy acts on the mitochondria of the cell, allowing them to produce energy more efficiently, which your body uses to perform its various functions in a more optimal manner. This article on red light therapy for pain provides a good explanation on the various mechanisms of the treatment.


This temporary redness and tightness is more common in people who are sensitive to light. Some medications can also increase photosensitivity, making redness and irritation more likely. Side effects should disappear within a few hours, however.

Eye Strain and Sensitivity

While red light therapy has been shown to improve ocular health, it’s recommended to treat the eyes in small doses, no more than a few minutes at a time. Your eyes are extremely photosensitive and prolonged exposure to red and NIR could potentially cause damage. The natural brightness of red LEDs is generally enough to prevent people from staring directly at the light source, fortunately. NIR, however, is invisible to the naked eye, and experts don’t yet know the long-term effects on the eyes. For instance, retinal scanners use infrared light and are deemed safe for use, but exposure is usually not longer than a second or two, rather than the 10-20 minutes of the average red light therapy session.

If you’re using red light therapy on your face, we recommend using blackout goggles (each Rouge device comes equipped with a pair). While your eyelids do a fair job of blocking light, it can still cause irritation.

If your device is not pointed directly at your eyes, however, there is no risk of damage. Some people even enjoy the red glow, particularly before bed. Others may find it irritating or simply unpleasant. So it’s really up to you whether you choose to wear the goggles. You can also invest in a pair of welding goggles or glasses, which are designed to block infrared light, if you’d prefer to retain your ability to see.


This is typically a byproduct of eye strain and can be prevented using goggles as described above. It could also be a sign of dehydration. While red light therapy doesn’t cause dehydration, it could make your eyes more sensitive to light, which may cause or worsen headaches. We recommend drinking a glass of water before and after each treatment session.

increased bleeding in open wounds

By virtue of its ability to increase blood flow, red light therapy has been shown to make wounds that might be at risk of bleeding, potentially bleed more, or begin bleeding again. This is why we recommend refraining from using red light directly on wounds that have not stopped bleeding. This is kind of a "proof is in the pudding" type of scenario, as the vasodilating effects of the nitric oxide release that results from its use will directly affect a wound that has not fully coagulated yet.

Is Red Light Therapy At Home As Safe As Treatment In a Clinic or Spa?


The minimal risks and side effects of red light therapy make it the ideal home treatment. Unlike many therapeutic treatments involving lights and lasers, which can cause severe damage if used incorrectly and require a trained professional to administer, red light therapy can be used by virtually anyone. This has made it one of the most accessible - and affordable- therapeutic treatment options available today.


Personal red light therapy devices are also more powerful and effective than ever, as well, thanks to advances in LED technology allowing for more cost-efficient manufacturing. It is important, however, to make sure you’re getting the real deal when purchasing a red light therapy device. Most devices being sold online claim to emit light at wavelengths of 660 and 850nm (the sweet spot for therapeutic effects), but it’s difficult to verify these claims. Look for devices that are FDA-registered and that have undergone independent third-party testing.  

As with any new treatment, always check with your doctor before beginning red light therapy.

Recent testing by the Light Lab International in Allentown Pennsylvania has shown that Rouge Red Light Therapy devices are among the most powerful on the market. Rouge devices are also registered with the FDA as a low risk medical device indicated for the treatment of arthritis-related joint pain and stiffness, as well as for the relief of muscle spasms and minor muscle and joint aches.


Ready to join the growing number of people enjoying the many benefits of red light therapy right in the comfort of their own home? Check out the Rouge family of red light therapy devices, and get started on the road to better health, the safe way, today!


  • Hi Dawn – while we cannot make medical claims in terms of whether RLT can help with lymphedema, there may be anecdotal testimony as well as scientific studies that seem to indicate that it may be helpful in some cases.

    Rouge Team
  • I have lymphadema in rt. arm wear compression sleeve and gaulet every day,will red light therapy work for me?


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