We are reader-supported and sometimes earn a commission if you buy through a link on our site.

Red Light Therapy For Cold Sores: Say Goodbye To Fever Blisters?

Last Reviewed on May 1, 2024

Explore how red light therapy, a safe and non-invasive method, can reduce cold sore symptoms, promote wound healing, and possibly prevent future outbreaks.

Did you know that roughly 3.7 billion people (67% of the world’s population) have the herpes simplex virus type 1 (HSV-1) infection?

This virus is the main cause of oral herpes and is actually quite a common infection, which is often contracted during childhood (believe it or not) [1].

Traditionally, treating these recurrent skin conditions involved antiviral medications and creams. Nowadays, red light therapy has become an increasingly popular “new” remedy for treating a cold sore outbreak. While it isn’t a cure, it can help drastically reduce the severity of your symptoms.

This article examines how red and infrared light therapy can reduce inflammation and promote wound healing to alleviate the symptoms and appearance of these painful sores.

And yes, it is 100% safe to use!

Can Red Light Therapy Help With Cold Sores?

Yes, it can!

To clear things up, the herpes virus infection comprises two strains, namely:

  • Herpes simplex virus (HSV-1) – the main cause of oral herpes
  • Herpes simplex virus (HSV-2) – the main cause of genital herpes

Oral herpes manifests from exposure to the HSV-1 virus and symptoms typically start as sores on the mouth. Our focus today is on herpes simplex virus type 1 (HSV-1).

Man with cold sore, HSV-1 infection information

Red light therapy has emerged as a promising treatment for the dreaded cold sore. It does not produce heat like laser therapy and is a non-invasive and pain-free alternative to traditional methods.

Red light therapy emits wavelengths of near-infrared light that penetrate skin cells, specifically targeting the mitochondria – the tiny powerhouses of cells. This boost in mitochondrial function accelerates energy production and the production of adenosine triphosphate (ATP) – kind of like the cells’ batteries [2].

The increase of ATP has the benefit of:

  • New cell growth
  • Cell rejuvenation
  • Reducing inflammation
  • Promoting wound healing [2]

While red light therapy is not a cure for cold sores, a number of case studies have shown that it can help reduce symptoms significantly and possibly prevent future outbreaks.

For instance, a study was done on people who suffered from severe recurrent infections in the late ’90s. Patients treated with 690 nm light experienced fewer recurrences of the herpes simplex virus, with cold sores only returning after 37.5 weeks (compared to the 3 weeks in the control group) [3].

Another study involved 87 patients who were divided into two treatment groups: one group received placebo light therapy and the other received infrared light therapy (1,072 nm).

Treatment was given three times a day over a two-day period. Patients who underwent light therapy showed a decline in herpes labialis (HSL) lesions (i.e. cold sores), with a healing time of 129 hours as opposed to 177 hours in the placebo treatment group [4].

Person using lip-shaped red light therapy device

On a side note and to avoid confusion, all of these names refer to red light therapy:

  • Low-level light therapy
  • Low-power laser therapy
  • Non-thermal LED light
  • Soft laser therapy
  • Cold laser therapy
  • Biostimulation, photonic stimulation
  • Photobiomodulation and phototherapy

How Does Red Light Therapy Work For Cold Sores?

Now that we know red light therapy is an effective treatment, let’s dig a little deeper into how red light therapy works on a cellular level.

Cellular Level

Stimulation of Mitochondria

As we mentioned, red light stimulates the mitochondria in our skin cells using low-level wavelengths. This increase in ATP and blood flow means that our skin cells perform better. Red light therapy supports healthy cell formation. This encourages the healing process for skin conditions like cold sore lesions [5].

Collagen Production

Collagen is what gives our skin strength, elasticity, and structure. As we get older, we naturally produce less collagen, which leads to signs of aging.

In 2012, a study was conducted to test the improvement of skin quality, healing, and collagen production in people aged between 27 and 79. Researchers found that patients receiving red light had the most significant improvements [6].

Utilizing red light treatment increases collagen production which leads to improved skin quality and faster healing. It is also the quickest way to boost your self-confidence when those pesky lesions appear!

Reduced Inflammation

Studies into red light therapy revealed it has anti-inflammatory properties, which are crucial in reducing swelling and redness associated with cold sores. Red light therapy promotes wound healing, particularly when treating skin ailments such as fever blisters and acne [7].

Pain Relief

The symptoms of fever blisters are not at all fun – and I speak from personal experience. Tingling lips, water-filled blisters, headaches, intense itching, and prolonged pain can drive any sane person up the wall!

(Go away painful and bothersome sores!)

Studies have shown that red light therapy may be effective for pain relief associated with oral (or genital) herpes. This is because it reduces inflammation and stimulates blood circulation [7].

Some people have even anecdotally reported seeing benefits after just one treatment!

Impact On Herpes Simplex Virus Type 1 (HSV-1)

Hindering Viral Activity

The reality (and annoying thing) about the herpes virus is that once you have it, it stays with you forever. It lays dormant until something in your body – like a low immune system – triggers its onset [8].

While red light therapy does not kill the herpes virus, it’s used as a form of “damage control”. The trick is to catch cold sores as soon as the symptoms start to show.

Even if the fever blister is already filled with fluid, light therapy may still help to reduce the severity and duration of outbreaks by up to 2 to 3 days [9]. By improving the overall health of your skin with the help of red light therapy, the (skin) environment may be less conducive to infection.

Close-up of cold sore treatment with red light therapy

Preventing Recurrence

Light-based therapies, like red wavelength treatment, can help reduce the frequency of cold sore flare-ups. One study looked at the impact of low-intensity laser therapy (690 nm) on patients with recurrent perioral herpes simplex infection. Those that received treatment, on average, saw recurrence after 37.5 weeks – which was 12.5x longer [3]!

How To Use Red Light Therapy For Cold Sores

We’ve established that red wavelengths are safe to use as an effective form of skin and tissue repair – but how do you actually use it?

  • Opt for a red light therapy device that is specifically designed for the face, such as handheld or table-top devices, or panels.
  • Make sure your skin is dry. Remove any creams or ointment from the affected area as this can have an adverse effect on the treatment.
  • Wear protective eyewear. While red wavelengths are safe for the eyes, prolonged and unnecessary exposure can be harmful.
  • Different devices may have different instructions for positioning the device, but the rule of thumb is to keep the device a few inches away from the affected area.
  • Red and infrared light treatments range in duration from 5 to 20 minutes, depending on the severity of your symptoms. Usually, it’s best to start with 5-minute increments, three times a day for two days, and adjust the frequency as needed. The key here is to be consistent!

For the best results, you can combine red light therapy with other cold sore treatments.

Close-up of cold sore treatment application


Here are some frequently asked questions about red light therapy and cold sores.

Can I use red light therapy to prevent cold sores?

Red light therapy’s an effective cold sore treatment and can be used as a preventative measure. Not only does it help reduce inflammation, stimulate new cell growth, and promote quicker healing times when cold sores appear, but keeps the skin healthy and functional.

What is the best red light therapy for cold sores?

Red wavelengths or near-infrared wavelengths between 650 nm and 680 nm are best to use for fever blisters.

How long does it take to see results?

A 2013 study showed an average recovery time of 5 days (the total time it took for the blisters to completely heal) [4]. However, light treatment dosages and timelines may differ depending on the frequency of your flare-ups and severity of symptoms.

Should I put anything on my skin before using low-level light treatment?

No, your skin must be clean when using red wavelengths. Remove makeup, creams, and serums to yield the best results.

Final Thoughts

Red light therapy can be a highly effective treatment for oral herpes lesions, as well as mouth ulcers [10]. It eases your symptoms and offers a glimmer of hope in what can be a frustrating and painful experience, while also preventing future outbreaks!

While photobiomodulation isn’t a known cure for herpes, it is an effective form of “damage control”. It can help support healthy cell formation, from increasing collagen production to reducing inflammation.

All in all, red light treatment is brilliant for alleviating symptoms associated with this disease and gets my stamp of approval! Especially when combined with another cold sore treatment like an antiviral medication. You can’t go wrong with this non-invasive, pain-free alternative if you want to treat the symptoms and boost your self-confidence simultaneously.

If you’re keen to know more, check out Therapeutic Beams’ extensive research into the benefits of red light therapy.


  1. https://www.who.int/news-room/fact-sheets/detail/herpes-simplex-virus
  2. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2996814/
  3. https://pubmed.ncbi.nlm.nih.gov/10469307/
  4. https://pubmed.ncbi.nlm.nih.gov/23731454/
  5. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4148276/
  6. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3926176/
  7. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5523874/
  8. https://www.mayoclinic.org/diseases-conditions/cold-sore/symptoms-causes/syc-20371017
  9. https://www.webmd.com/oral-health/remedies-for-cold-sore
  10. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3972568/ 
Anne, Founder of Therapeutic Beams

Anne Linde

Since using it to clear up her acne in college, Anne has been an avid user and fan of all things light therapy. She now primarily uses red light therapy for its anti-aging benefits. Anne's mission is to make the science behind red light therapy easy to understand and accessible, so anyone can use it to take control of their health and wellbeing.

John Ni, BSc.

John, a graduate of the prestigious University of Pennsylvania, serves as a respected scientific reviewer at TherapeuticBeams.com. His expertise extends across various domains, including chemistry, pharmaceuticals, and dermatology. He contributes to publications like Royal Society of Chemistry, Drug Topics, and Practical Dermatology.

John Ni, Content Editor & Scientific Review

Leave a Comment