Acne Light Therapy: What Works, What Doesn’t, and How to Know if It’s Right for You

Jeff Hautala
By Jeff Hautala, Co-Founder of Exposed Skincare

Acne light therapy is one of the biggest innovations that acne treatment has seen in the last decade. At first it may seem like just another fad; I mean, how can shining a light on your skin for a few minutes do anything? But the science behind acne light therapy is actually incredibly solid. Unlike other acne fads, like using toothpaste as a spot treatment, there is substantial research suggesting that light therapy can be an effective treatment for acne.

Light Therapy for Acne
Many dermatologist’s offices provide light therapy for acne treatment.

What is Acne Light Therapy?

Okay, so there’s research that proves light therapy works, but…what is it exactly? Acne light therapy is a form of treatment that involves shining a particular kind of light on the skin for a short period of time. Blue light works by destroying the bacteria associated with acne, and red light works by reducing inflammation and oil production. Photodynamic therapy, a specialized form of light therapy typically reserved for especially severe acne, can work either way, depending on which color light is used.

Who Can Benefit From Acne Light Therapy?

There are three main causes of acne: inflammation, bacteria, and oil production. All three factors play a role in acne formation, but sometimes one or two factors are the predominant cause. For example, many teenagers experience increased acne because their sex hormones are fluctuating, which leads to an increase in oil production. Because light therapy primarily targets acne-causing bacteria and excess oil production, it is most effective for people whose acne is caused by those two factors. So how can you tell what’s causing your acne?


  • Inflammation is the root cause of acne. Without inflammation, bacteria and oil production would rarely become an issue, but unfortunately, our skin is almost always inflamed at least a little. This is because of the vast variety of things that can cause inflammation, including emotional stress, physical irritation, hormone fluctuations, and more.
  • When the skin is inflamed, it swells slightly, and this can cause the pores to constrict or even close, trapping oil, dead skin cells, and bacteria. Once trapped, these can all lead to increased acne in one way or another. Your acne might be caused primarily by inflammation if you have blackheads, whiteheads, or pimples, and your skin generally has a reddish or uneven skin tone. Redness is one of the visible signs of inflammation, and inflammation contributes to all kinds of acne.
  • Red light therapy can help with inflammation, but unless you’re using photodynamic therapy, it is a temporary solution. Red light can soothe skin that is already inflamed, but it won’t prevent your skin from getting inflamed in between treatments. This is one reason we caution people about using acne light therapy alone, and recommend using a full acne treatment system as well.


  • Bacteria may be the biggest cause of your acne if you typically have pimples or cysts, but bacteria aren’t inherently bad. The bacteria associated with acne are called p. acnes, and when they aren’t trapped in a pore due to inflammation, they can actually help keep skin clear. This is because p. acnes’ main food source is the oil produced by our skin. The bacteria consume oil and help prevent buildups and clogs which can lead to blackheads and whiteheads.
  • If p. acnes bacteria do get stuck in a pore, however, they can definitely cause a problem. Oil typically gets trapped as well, so the bacteria have extra food, which helps their numbers grow much faster than normal. Eventually, there are enough bacteria for the body to register them as a minor infection. This causes the immune system to send immune system agents out to kill the bacteria, and generate more inflammation, which is why pimples and cysts are more raised and painful than blackheads or whiteheads. In the process of destroying the bacteria, the immune system cells usually destroy themselves as well, and all the dead cells combine to form pus, which is what gives pimples and cysts their yellowish color.
  • If you typically have pimples, acne light therapy can be a great option for you. Regular light therapy may not be strong enough for cystic acne, but photodynamic therapy may be able to help.

Oil Production:

  • If you typically have blackheads and whiteheads, oil production may be the primary cause of your acne. We’ve already seen how oil production can contribute to the formation of pimples and cysts if bacteria are involved, but even without bacteria, excess oil can still cause acne.
  • Oil is produced by the sebaceous glands, which lie beneath the outer layer of the skin. Once oil is produced by the glands, it’s released and it travels toward the surface through a pore. Having some oil is good because it can help protect your skin from mild irritants. But too much oil is a problem because it can get backed up in the pore and cause a clog, and if there’s any inflammation, blackheads and whiteheads are likely to form.
  • Red light therapy may be helpful if you mostly have acne caused by oil. It can be very effective in treating blackheads and whiteheads because it causes a reduction in oil production.

The Science Behind Acne Light Therapy

Before we can dig into how light therapy works, it’s important to know that there are four main types of light therapy for acne: blue light, red light, combined light, and photodynamic therapy. Each works in a slightly different way, but each has been proven to be effective in fighting acne to some degree.

Blue Light:

  • If your acne is mostly made up of pimples, acne light therapy using blue light is the best option, because the frequency of blue light can kill p. acnes bacteria. Light travels like a wave, meaning it has a frequency, just like sound, and this frequency can interact with the world in a very physical way. Blue light can kill p. acnes is because its frequency matches the resonant frequency of the bacteria.
  • Think of it like the opera singer who shatters a glass by singing exactly the right note. If you hit a glass softly and listen close, you will hear a soft tone. This is the glass’ resonant frequency, and when the opera singer sings a note that matches that resonant frequency exactly, the sound waves crash and the glass shatters. Something very similar happens with blue light and bacteria.
  • Light waves move much too quickly to shatter glass. But they can shatter the cell walls of p. acnes bacteria. Just like the glass from the opera example, bacteria have resonant frequencies, and blue light matches the resonant frequency of p. acnes exactly. When exposed to blue light, the cell walls of p. acnes start to disintegrate, effectively killing them. Blue light can’t kill all p. acnes bacteria because they always live on the skin to some extent, but it can help kill the excess bacteria involved in a minor infection, like a pimple.

Red Light:

  • Acne light therapy using red light is most effective when treating blackheads and whiteheads, because it decreases oil production by providing a gentle heat source that won’t dry out your skin.
  • Blue light works because of its frequency, and red light works because of its wavelength. Wavelength on the visual spectrum determines the color of the light you see. Blue, for example has a relatively low wavelength, approximately 450 nanometers. Red has a high wavelength, around 700 nanometers, and it is the last visible color before invisible infrared light. Although we can’t see infrared, we can feel it in the form of heat.
Light Therapy for Acne
We can see the visible spectrum of light when white light gets distorted in bubbles.
  • You may have heard that tanning can help reduce acne because of exposure to the sun, but this is only somewhat true. The sun radiates infrared light, and with brief exposure, this heat can soften the oil trapped in the pores to help it escape, and it can shrink the sebaceous glands so less oil is produced. The trouble is, tanning doesn’t only involve infrared light. Harmful UV rays produced by the sun are likely to cause your skin significant damage, especially if you’re exposed to it consistently for long periods of time.
  • Red light therapy works better because it doesn’t include any of those harmful rays, and it is milder than pure infrared light. Because it softens oil and shrinks sebaceous glands, red light can both treat and prevent acne to a certain extent.

Combined Light Therapy:

  • If you have blackheads, whiteheads, and pimples, and you aren’t sure what exactly is causing your acne, then it might be hard to decide which kind of acne light therapy to try, red or blue. Because most acne is caused by a variety of factors, many sources of light therapy now offer combined light which uses both blue and red light. This simply combines the effects of both colors of light, and many studies have found it to be significantly effective in treating mild acne.

Photodynamic Therapy:

  • The last acne light therapy option is photodynamic therapy, and it is typically used for more severe acne, including cystic acne. Unlike plain blue light or red light, photodynamic therapy is only available at a dermatologist’s office, and it involves several steps.
  • First, the skin undergoes microdermabrasion, which exfoliates the skin to remove excess dead skin cells and makes it easier for the therapy to work. Next, a photosensitizing agent is applied and left on the skin for anywhere from 15 minutes to an hour. This just makes the skin extra sensitive to light so it can absorb even more of the effects of the light. After the allotted time, the photosensitizing agent is removed, and the light is applied. Many offices are now using combined light so you can receive the benefits of both, but some offices only offer one or the other.
  • The biggest difference between normal light therapy for acne and photodynamic therapy is the pain. Typically, light therapy is painless, but photodynamic therapy is reported to cause pain that is moderate to severe. Some reports say that this has lessened in recent years, but it is not yet pain-free.

Where to Get Acne Light Therapy

When light therapy for acne was first developed, it was only available at a dermatologist’s office. Now, there are all kinds of at-home devices, but many dermatologists still offer light therapy services. At-home devices are much more convenient, and depending on which option you choose, they can be significantly cheaper than regular visits to the dermatologist, but there is a major downside: their light is not as effective as the light available through a dermatologist. Light therapy can be effective in treating acne both at home and at the dermatologist’s office, but people typically see better results from professional light therapy.

Either way, light therapy alone is not enough to get clear skin. It may reduce inflammation slightly, kill 50% of bacteria, and decrease oil production, but using a full acne treatment system along with light therapy for acne is far more effective. We recommend using Exposed Skin Care’s 3-step system. Together, Exposed and light therapy can significantly reduce acne and give you clearer skin.

The Exposed 3-step process includes a Facial Cleanser and a Clearing Toner, both used in the morning and at night, an Acne Treatment Serum, used in the morning, and a Clear Pore Serum, used at night. Each step of the Exposed process includes both scientific and natural ingredients, to ensure your skin is getting the care it needs while fighting acne. Unlike many other acne treatment systems, we use low concentrations of key acne-fighting ingredients, like benzoyl peroxide and salicylic acid. High concentrations of these ingredients can get rid of acne in a few short days—but then it comes back just as fast because those high concentrations dry out the skin, leading to inflammation and excessive oil production. By treating your skin gently, we reduce acne for the long-term.

Acne Light Therapy: What Works, What Doesn’t, and How to Know if It’s Right for You
The best way to treat acne is with gentle, consistent care, which is exactly what our Basic Kit is designed to do.