KO Light: What is the difference between red and blue light? How to choose based on wrinkles and acne

LED light therapy like KO Light changes its target depending on the color (wavelength) of light applied, with red light and near-infrared light used for fine lines and skin firmness, and blue light used for acne[1][2]. For crow's feet, improvement has been confirmed in tests compared to sham devices, but Japanese guidelines do not recommend it for acne[1][3]. Depending on your concern, the light color you choose and the magnitude of your expectations will differ.

What changes with light color?

What changes is the depth the light reaches and what it targets within the skin. Red light reaches 4–6 mm into the skin, penetrating deeper than blue light's 1–2 mm[4].

Red light and near-infrared light are thought to be absorbed by the part of cells that produces energy (mitochondria), and to support cellular function.[1]As a result, cell experiments have shown that collagen and elastin, which support skin firmness, increase.[1].

Blue light (407–420 nm) is said to reduce acne-causing bacteria, and red light (620–750 nm) is said to reduce inflammation.[2]Which color of light KO Light emits depends on the device and settings, so confirm this before treatment.

If the goal is wrinkles and firmness, how much improvement can be expected?

For fine lines around the eyes, gradual improvement can be expected. In a trial where 60 people aged 30–65 used a mask emitting 630 nm red light and 850 nm near-infrared light for 16 weeks, wrinkles around the eyes improved in 86.2%.[1].

Compared to people who used a fake mask without light, the rate of improvement was 69.5 percentage points higher, with a difference appearing from week 8.[1]No serious side effects occurred.[1].

However, this is research on a mask used daily at home, and the frequency and intensity of illumination at a clinic are not the same. It is also important to know the limitation that this is not a treatment to lift and reduce sagging or deep wrinkles.

If the goal is acne, which should you choose—red or blue light?

Blue light has been used extensively in research. A report summarizing 35 studies (1,185 cases) found that blue light was used in approximately 64% of cases, and acne partially improved in 95% of people treated with blue light.[2].

However, within "partial improvement," a reduction of less than half was most common at 44%, and acne does not completely clear.[2]The average time to see results is about 4 weeks, and the average number of sessions is 22, making ongoing visits a prerequisite.[2].

In a 28-person trial directly comparing red and blue light, acne reduction after 2 weeks was 36.2% for red light and 30.7% for blue light, with no clear difference.[5]Side effects were more notable in the blue light group.[5].

What are the limitations of light therapy for acne treatment?

Using light therapy alone to treat acne is not recommended in Japan. The Japan Dermatological Association guideline classifies blue light therapy as "not recommended (C2)" due to equipment issues and insufficient domestic evidence.[3].

A report summarizing 13 trials (422 people) of red light therapy also showed no clear additional benefit compared to other treatments.[6]For people with acne, the practical approach is to first receive standard treatments such as topical medications, then consider light therapy as an adjunct.

What are the guidelines for side effects and downtime?

Downtime is minimal, though mild irritation may occur. Blue light caused mild side effects in 13%, most commonly irritation, redness, and dryness.[2].

When red and blue light are applied together, dryness and redness may temporarily appear.[2]If you are taking medications that increase light sensitivity or have a skin condition that worsens with light, please inform the clinic beforehand.

What should be confirmed during consultation to find the right light for you?

What we want to confirm is whether your concerns are fine lines and skin firmness, inflamed acne, or sagging skin. This determines whether red and near-infrared, blue, or non-light treatments should be the primary focus.

Also ask about what color light, at what intervals, and how many sessions will be used, and whether other treatments will be combined. Since the article cannot determine which light is right for you, it is best to have your skin examined in person and consult with a doctor to decide.