Walk into any beauty store and you will find LED masks claiming to treat everything from acne to wrinkles using a rainbow of coloured lights. Blue, red, green, yellow, near-infrared. Each with its own set of promises.
But here is what most brands do not tell you: different wavelengths of light have very different effects on melanin-rich skin. And one of the most popular light therapy treatments actively worsens hyperpigmentation in darker skin tones.
Here is what the science actually says.
Understanding light wavelengths
Light therapy devices use specific wavelengths of light measured in nanometres. Different wavelengths penetrate the skin to different depths and trigger different biological responses.
The most commonly used wavelengths in LED skincare devices are blue light between 415 and 460nm, green light at around 520nm, yellow or amber light between 570 and 620nm, red light between 620 and 700nm, and near-infrared light between 700 and 1000nm.
Each wavelength has a different depth of penetration and a different mechanism of action. And for melanin-rich skin, this distinction is not just academic. It has real consequences for your skin.
Blue light and dark skin: the problem
Blue light therapy is widely marketed for acne treatment. It works by targeting and neutralising Propionibacterium acnes, the bacteria responsible for inflammatory acne breakouts. In clinical studies on lighter skin tones, it has shown effectiveness for this purpose.
But for melanin-rich skin, blue light presents a significant risk that is rarely disclosed.
A 2024 peer-reviewed study found that in darker skin phototypes, Fitzpatrick IV to VI, blue light may worsen hyperpigmentation through a mechanism called Opsin-3 mediated melanogenesis. In simple terms, blue light activates a light-sensitive receptor in melanocytes called Opsin-3, triggering increased melanin production.
The same light that clears acne bacteria can simultaneously stimulate your melanocytes to produce more pigment, potentially worsening the very dark marks that post-acne hyperpigmentation causes.
This is not a theoretical risk. It is a documented biological mechanism that is more pronounced in skin with higher melanin density.
What this means for your LED mask
Many LED masks include blue light as a standard mode. If you have melanin-rich skin and you are using blue light regularly for acne treatment, you may be inadvertently worsening your hyperpigmentation at the same time.
This does not mean you need to avoid blue light entirely. Used carefully and infrequently, it can still be beneficial for active acne. But it should never be your primary skincare mode if you are concerned about dark spots or uneven skin tone.
Red light and dark skin: the evidence
Red light therapy at 630nm tells a completely different story for melanin-rich skin.
Unlike blue light, red light does not activate melanin-producing receptors. It bypasses melanin entirely and works at the mitochondrial level, activating cytochrome c oxidase inside your cells to increase ATP production, reduce inflammation and stimulate collagen synthesis.
A 2024 systematic review in Photodermatology, Photoimmunology and Photomedicine found that red light at 630nm significantly reduces melanin content by modulating tyrosinase activity, the enzyme responsible for melanin production. Far from worsening hyperpigmentation, red light actively reduces it at the cellular level.
The National Institutes of Health STARS trials confirmed that red LED light is safe for all skin tones including Fitzpatrick V and VI at therapeutic doses, with no increased risk of hyperpigmentation or adverse effects.
Near-infrared light: the deepest benefits
Near-infrared light at 850nm penetrates deeper than any other wavelength used in home LED devices, reaching 5 to 10mm beneath the skin surface into the dermis.
At this depth, it stimulates fibroblasts to produce collagen and elastin, reduces deep inflammation, and according to a December 2024 clinical study, is uniquely effective at treating existing post-inflammatory hyperpigmentation rather than just preventing new marks from forming.
Near-infrared is invisible to the naked eye, which is why some users assume their device is not working when this mode is active. But the absence of visible light does not mean absence of effect. Near-infrared delivers some of the most clinically significant benefits of light therapy precisely because it works beneath the surface.
Yellow and green light: supporting roles
Yellow light at 590nm has been shown to reduce redness and improve lymphatic drainage, supporting skin healing and reducing inflammation. It also has some evidence for melanin reduction, making it a useful complementary wavelength for melanin-rich skin.
Green light at around 520nm has mild melanin-inhibiting properties in some studies, though its evidence base is less robust than red and near-infrared.
Neither yellow nor green light carries the hyperpigmentation risk associated with blue light, making them safer choices for melanin-rich skin.
The Lumara protocol: wavelengths chosen for dark skin
The Lumara mask offers four wavelengths: blue at 460nm, yellow at 590nm, red at 630nm and near-infrared at 850nm.
For melanin-rich skin, the recommended primary mode is Red and Near-Infrared combined. This delivers the most clinically validated combination for hyperpigmentation treatment, collagen stimulation and skin rejuvenation without any risk to melanin production.
Yellow light can be used as a complementary mode for redness and inflammation support.
Blue light should be used sparingly and only when treating active acne breakouts, not as a routine mode. If you have significant hyperpigmentation concerns, it is best avoided entirely until your skin tone has evened out.
The bottom line
Not all light therapy is equal, and for melanin-rich skin the difference matters.
Blue light can worsen hyperpigmentation in darker skin tones through a documented biological mechanism. Red light at 630nm and near-infrared at 850nm actively reduce hyperpigmentation, stimulate collagen and are clinically proven safe for all skin tones.
The Lumara protocol is built around this science. Red and near-infrared, every Monday, Wednesday and Friday, 15 minutes at a time.
Lumara. The light therapy ritual for melanin-rich skin.