LED light therapy for acne: blue, red and masks

Light looks like the easiest acne treatment there is. You hold a glowing device to your face, or wear a mask for twenty minutes, and nothing stings or peels. The American Academy of Dermatology starts its page on the subject in almost those words, then adds the part that matters: using them is more involved and the results are less predictable, even in the skilled hands of a dermatologist.

That does not make light therapy useless. It means light therapy has a narrow use. It works on inflamed spots only, it needs repeating, and it works better alongside a cream than in place of one. This Skinli guide explains what blue and red LED light can treat, what it cannot treat, how long it takes, and when a light device is the wrong answer to the problem you have.

What blue and red light are supposed to do

LED stands for light emitting diode. It is the small part that makes the light, the same component in a phone flashlight or a television screen. In skincare it is used to send a narrow band of one color at the skin.

The American Academy of Dermatology calls blue, red, and blue plus red devices visible light, named that way because you can see the colors. Blue is the color tied to acne. Red is usually added to it rather than used alone.

The colors are specific, not decorative. A US Food and Drug Administration clearance document for an over-the-counter acne device describes two types of LED in one unit: 630 nanometer red and 415 nanometer blue. The same document says devices in this category use "red and blue diodes with 630 nm and 415 nm to provide narrow bands of light energy to treat acne". A nanometer is the measure of a light's wavelength, and the wavelength is what decides the color your eye sees.

What it treats, and what it does not

This is the sentence to read twice before buying anything. The AAD says visible light devices can treat pimples, and that visible light is not effective against blackheads, whiteheads, acne cysts or nodules.

So light therapy aims at one target: the inflamed red spot. The FDA clearance language matches that. The device category is written as treatment for "mild to moderate inflammatory acne", and inflammatory is the word that rules out the rest.

Acne you have	Can visible light treat it?
Pimples (red, inflamed spots)	Yes, according to the AAD
Blackheads	No
Whiteheads	No
Acne cysts	No
Acne nodules	No

If your main problem is blackheads on the nose or closed bumps on the forehead, a light device is pointed at the wrong thing. Those respond to a retinoid or a chemical exfoliant instead, which the guide on what causes blackheads covers. If your acne is deep, painful lumps under the skin, read cystic acne and see a doctor, because light is listed as unable to treat cysts and nodules.

Light alone rarely clears acne

The AAD is direct about this: rarely can these treatments alone clear acne. To give the best results, it says, your dermatologist may recommend using another acne treatment, such as medicine that you apply to your skin.

That puts light therapy in the role of an addition. The ingredients with the strongest evidence stay the base of a plan: benzoyl peroxide and a topical retinoid such as adapalene. Skinli's guide to the best acne treatments sets out how the guidelines rank them, and the hub page on how to get rid of acne gives the step by step version.

The AAD also says results vary from person to person, and that right now there is no way to know who will see clearer skin or how much the skin will clear. Nobody can tell you in advance whether you are someone a light device helps.

How long it takes, and how many sessions

Light therapy is not a one-evening treatment. The AAD says that to get results, most people need a series of treatments, and that several studies have shown multiple treatments deliver better results than a single treatment.

The timing is slower than people expect. Researchers continually find that patients see the best results weeks after the last treatment, the AAD says. The figures it gives come from a study of photodynamic therapy, a clinic treatment described further down: patients had 50 percent fewer spots at the end of the 4 week treatment period, and twelve weeks after the last treatment they had a 72 percent reduction.

Results from lasers and light therapies are generally long lasting, the AAD says, but to keep them patients often need follow-up treatments once or twice a year.

Twelve weeks is also the number the rest of acne care runs on. The UK NICE acne guideline says to review a first treatment at 12 weeks and assess whether the acne has improved and whether there are side effects. Skinli's guide on how long an acne routine takes to work explains why that wait is normal.

At-home devices and face masks

At-home LED devices and face masks are the version most people actually buy. The AAD says the FDA has approved some visible-light LED devices (blue, red, and blue plus red) for at-home use, and that these devices are less powerful than the ones a dermatologist uses.

The time commitment is the part the marketing tends to leave out. If you want to give it a try, the AAD says, you will need to use an at-home device twice a day, and some devices need 30 to 60 minutes twice a day for 4 to 5 weeks. Twice a day for a month, at up to an hour a session, is a real demand on a day.

Two practical points follow from that. First, use the instruction sheet that came with your own device, because the schedule differs between models. Second, the AAD repeats here that visible light can only treat pimples and that there is no way to know who will see results.

A mask and a handheld wand are the same technology in different shapes. Neither changes what the light can reach.

Side effects are possible

A treatment with no sting still has side effects. The AAD says redness and swelling are common after treatment with many lasers and light treatments, and that some patients say their skin stings or burns. These are usually mild and disappear within a few hours or by the next day.

Rarer problems do happen. The AAD lists lingering pain, burns and blisters, and says changes in your skin color and scarring are also possible. Getting treatment from a board-certified dermatologist who frequently uses lasers helps prevent side effects, and patients need to follow the instructions they are given before and after treatment.

Skin color change is worth attention if you have a deeper skin tone, because dark marks after inflammation are already the main concern there. Skinli's guide on acne on darker skin explains that pattern.

Eye protection is standard on these devices for a reason. If a device came with goggles or a shield, use them.

Photodynamic therapy is a different, stronger treatment

Photodynamic therapy, often written PDT, is the clinic treatment people sometimes confuse with a home LED mask. It is not the same thing.

In PDT, the AAD explains, a solution that makes the skin more sensitive to light is applied to acne-prone skin. The solution sits on the skin for between 15 minutes and 3 hours. A dermatologist then uses a laser or light device on the skin. Afterwards, patients must avoid sunlight for 48 hours.

The results reported are stronger than for plain light. The AAD says PDT shows great promise in helping to treat severe acne, and that some patients who had acne cysts have been clear for years after receiving PDT from a dermatologist.

NICE places it carefully. Its acne guideline says to consider photodynamic therapy for people aged 18 and over with moderate to severe acne if other treatments are ineffective, not tolerated or contraindicated. That is a treatment reached for after the usual ones have been tried, given by a clinician, for people over 18.

Two other clinic options sit alongside it. The AAD says the FDA has approved infrared light to treat pimples, including those on the back, and that it cannot treat blackheads, whiteheads, cysts or nodules. Photopneumatic therapy combines an intense pulsed light laser with a gentle vacuum to remove oil and dead skin cells from clogged pores, and is approved to treat blackheads, whiteheads and some pimples, but not nodules or cysts.

When a light device is the wrong purchase

Light therapy is a reasonable thing to add if your acne is mild inflamed spots, you already use benzoyl peroxide or a retinoid, and you can keep to twice a day for several weeks.

It is the wrong purchase in a few clear cases. If your acne is mostly blackheads or whiteheads, the AAD says visible light does not work on them. If you have painful lumps or cysts, light is listed as unable to treat them and a dermatologist has better options. If you want one treatment that replaces your cream, the AAD's own sentence says light rarely clears acne alone. And if you have not yet tried the treatments with the strongest evidence, those come first.

See a doctor for acne that is deep or painful, acne that leaves scars, or acne that has not improved after a few months of steady treatment. Skinli gives education and is not a doctor. A dermatologist can also tell you whether you are a good candidate for a laser or light treatment at all, which is what the AAD advises asking.

If you want to know which type of acne you are looking at before you spend money on a device, the photo check gives you a count of spots and the type it sees.