Light therapy is a popular skin treatment with dermatologists, estheticians, and the public. In this article, we’ll discuss light therapy as a safe and effective acne treatment backed by clinical research. We’ll break down the science and explain the difference between red light therapy and blue light therapy for acne.
What Is Light Therapy?
A light therapy device isolates therapeutic wavelengths of light and shines them on the body and cells. Light treatments have been shown to reduce inflammation and stimulate skin rejuvenation and healing in clinical trials. [1,2,3] Light therapy has also shown positive results for treating acne on the face and reducing the appearance of acne scars. [3,4,5,6,7,8,9]
Light therapy treatments for acne are well-tolerated and produce few side effects, especially compared to other acne treatments like peels and medications. [8,9,10] Blue light and red light are the most commonly used wavelengths for acne spot treatments.
You can go to dermatologists or estheticians for professional light therapy sessions or use personal treatment devices in your home. In either case, consistency and proper use is key for effective light therapy acne treatments.
LED Acne Treatments: Blue or Red Light Therapy?
Blue light and red light are the most common wavelengths used to treat acne, and they both have positive effects on acne and skin. Research is showing that light therapy may be most effective for acne when red and blue light therapy are used together. [5,6,7,8,9] Let’s start by breaking down the difference between blue light and red light spot treatments for acne.
Blue light therapy is used against acne because wavelengths of blue light have an antimicrobial effect, killing bacteria on the skin that gathers in pores and oil glands and causes acne breakouts. [3,10] In clinical research, blue light has been effective for acne treatment, inducing “photodynamic destruction” of bacteria on the skin.  Blue light can also help eliminate free radicals that oxidize on the face. You can buy numerous blue light therapy masks and wands online or from beauty retailers.
Red light therapy isn’t antimicrobial like blue light. Instead, wavelengths of red light have an anti-inflammatory effect on the skin and promote the healing of skin and acne scars. [1,2,3] While blue light kills acne-causing bacteria on the surface, red light works below the surface and in the cells, helping to repair damaged tissues and rejuvenate the skin from within.
Both red light therapy and blue light therapy have positive effects on acne. Using wavelengths of both red and blue light to treat acne is effective against bacterial and inflammatory acne, as shown in peer-reviewed clinical research.  And both red and blue light therapy are proven to be well-tolerated with few side effects. [1,2,5,6]
As for near-infrared (NIR) light, research shows it’s less effective for acne than red light therapy. . One trial compared red light versus NIR light for acne and determined that red light therapy is “safe and effective to treat acne” compared to NIR light, which doesn’t work as well. 
In the next section, we’ll break down the research on light therapy and acne and explain the science behind how wavelengths of red and blue light can have a healing effect on acne.
How Does Light Therapy Work for Acne?
This post goes into detail about how light therapy works for skin and skin healing. Blue light therapy works by killing the harmful bacteria that gathers on the skin and causes acne. Red light therapy works by reducing inflammation, rejuvenating skin, and diminishing scarring on the skin. [1,2,6,9]
Red light therapy helps heal skin and acne because the mitochondria in our skin cells absorb wavelengths of red light and use it to make cellular energy and reduce oxidative stress and inflammation. [13,14] A recent clinical review said “LEDs represent an emerging modality to alter skin biology and change the paradigm of managing skin conditions.” 
Recent research is showing that the combination of both blue and red light therapy can be an even more effective acne treatment than just one or the other. Below, we’ll summarize some of the recent trials and studies that show how red and blue light work together to treat and heal acne outbreaks.
Blue and Red Light Therapy May Suppress Sebum Production
Acne vulgaris is a chronic inflammatory disease characterized by an increase in the body’s sebum production.  Combination blue and red light therapy has reduced acne in clinical trials and shown a significant decrease in sebum production after LED treatments. [5,9]
Clinical data shows that red light and blue light used in tandem strongly downregulate lipid production in sebocytes, the cells that produce sebum (skin oil). Trial results suggest that roughly 415 nm blue light and 630 nm red light wavelengths, when used together, can have beneficial effects on acne by suppressing sebum production. 
Blue and Red Light Therapy with LEDs Is Safe and Effective for Acne
A 2013 clinical trial evaluated light therapy acne spot treatments done with an at-home LED device. Patients with moderate acne were separated into two groups: a control group that treated their faces with a sham device, and an LED group that treated their faces with blue and red wavelengths for 2.5 minutes every day for a month. 
No significant difference in acne was seen in the control group. The light therapy group, however, saw major improvements in their acne. Both inflammatory and noninflammatory acne lesions decreased significantly after LED treatments. Inflammatory acne decreased by 77% with light therapy, while noninflammatory acne decreased by 54% with light therapy. 
The researchers also reported that the treatment group saw a reduction in sebum production. They concluded that LED phototherapy was “safe and effective for treating not only inflammatory but also noninflammatory acne lesions.” 
A separate trial published in the Journal of Drugs in Dermatology concluded that “blue and red light combination LED phototherapy is an effective, safe and non-painful treatment for mild to moderately severe acne.” 
In the trial, people’s acne lesion counts progressively reduced through a four-week LED light therapy treatment period. The final average reduction of people’s acne was 69% after LED treatments with blue and red light. Patients in this trial also reported brightened skin tone and improved skin texture. 
Where To Do Light Therapy Treatments for Acne
Light therapy acne treatments are widely available in both professional and at-home settings. Phototherapy has become a very common and popular acne treatment among dermatologists . If you choose to see a dermatologist for light therapy, you could pay $40-50 per session, but depending on the area and prestige of the clinic, light therapy acne treatments can cost as much as $100 per session.
The problem with professional light therapy acne treatments is the cost in both time and money. Light therapy works much better when done consistently, ideally every day for skin conditions like acne and cold sores. For acne, you need light therapy sessions for at least a few weeks to see results. Daily or even weekly treatments with a dermatologist or salon add up quickly, and most people just can’t spend thousands of dollars and hours of time on light therapy treatments every month.
The majority of people treating acne with light therapy prefer to use a personal, at-home device with a one-time cost (usually between $50 and $400 depending on the device). These are ideal for acne because you can do sessions every day in just a few minutes each. At-home light therapy treatments save a lot of money and time versus going to a dermatologist or spa, and they tend to be more effective because you can do them more consistently.
What type of treatment or device should you choose for acne? The most effective products treat the skin with both red and blue wavelengths. You should also make sure any device is safety-tested and approved for facial skin treatments. Learn more about available types of light therapy products in this article.
Light Therapy vs. Other Acne Treatments
Over 50 million people have acne concerns in the United States alone. Thousands of different products exist to treat acne, including prescription drugs, topical medications, and beauty products like washes and peels. [3,10] The biggest problem these products share is a wide range of potential side effects, especially skin irritation and bacterial resistance. 
The most commonly used topical medications for acne include retinoids and retinoid-like drugs that come in creams, gels, and lotions, like Retin-A, Differin, and Tazorac.  These work for some people, but can also cause increased sun sensitivity, dry skin, and redness, especially in people of color. 
Azelaic acid and salicylic acid in creams or peels are also used for acne treatments because of their antibacterial effects. Dapsone is a gel used for inflammatory acne and can cause side effects like dryness and redness. Oral medications like tetracycline are used to treat more severe acne. Oral acne drugs can increase sun sensitivity and antibiotic resistance. 
One major advantage light therapy has over other acne treatments is fewer potential side effects. In a wide range of clinical trials and populations, LED light therapy with red and blue wavelengths has proven safe and well-tolerated for people with acne, causing virtually no side effects. [1,2,3,6,10]
With an at-home treatment device, light therapy is just as quick and convenient as a face wash or topical product. Most devices require only two to five minutes of acne spot treatments per day.
Chemical Peels vs. Light Therapy for Teenagers with Acne
Research has shown that LED light therapy is more effective against acne than certain chemical peels.  A 2017 trial with teenagers compared light therapy acne spot treatments with salicylic acid peels. Teens with acne were divided into two treatment groups, with some receiving acid peels and others receiving spot treatments with red and blue light therapy.
Using photographs to track the progress of the teenagers’ acne, researchers found that the light therapy treatments worked significantly better than the acid peels. Teens in the light therapy group showed significantly fewer new acne pustules after light therapy. 
The researchers concluded that combination blue and red light therapy is effective against acne due its anti-inflammatory and wound-healing properties.  You can read more about light therapy for wound healing here.
Risks and Side Effects of Light Therapy Treatments
In clinical settings, light therapy acne treatments have proven to be generally safe and well-tolerated. [1,3,10] The simple, noninvasive nature of light therapy is one of the reasons it has become such a popular acne treatment, especially when compared with some acne medications and chemical peels that can cause major side effects.
Light used in LED treatments is not ultraviolet (UV) like sunlight, so the risks of skin damage from UV rays does not exist with light therapy. However, there are certain risks from light therapy treatments for people with sensitive skin and for people who are taking certain antibiotics.
If you’re overly sensitive to sunlight or easily burned from sun exposure, you may be at greater risk of skin irritation from light therapy. There is also a mild risk of infection for anyone if the treatment area isn’t cared for. In the event of blisters, redness, pus, or other adverse effects from light therapy treatments, contact a trusted healthcare provider. [3,8,10]
Acne treatments involving light therapy or other methods can come with heightened risks for pregnant women. Women who are pregnant or who may become pregnant are generally instructed to steer clear of most acne treatments to avoid risks and side effects.  Consult a trusted healthcare provider if you have any questions about acne treatments and pregnancy.
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 Mayo Clinic. Acne Diagnosis and Treatment.
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 Kwon HH, Lee JB, Yoon JY, Park SY, Ryu HH, Park BM, Kim YJ, Suh DH. The clinical and histological effect of home-use, combination blue-red LED phototherapy for mild-to-moderate acne vulgaris in Korean patients: a double-blind, randomized controlled trial. Br J Dermatol. 2013 May; 168(5): 1088-94.
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