LED light therapy works because different wavelengths of light interact with skin tissue at different depths, triggering specific biological responses. It's not a one-size-fits-all technology — the colour of light you use determines what it actually does. Understanding that makes it much easier to use a multi-wavelength device like the Déesse PRO LED Mask with intention rather than guesswork.
Here's what each wavelength does, and when to reach for it.
Blue light — 415nm — for breakouts and congestion
Blue light operates at the surface of the skin. At 415nm it targets Cutibacterium acnes — the bacteria responsible for inflammatory acne — by activating porphyrins within the bacterial cell walls, which then produce reactive oxygen and destroy the bacteria from the inside. It's one of the most studied applications in LED therapy and has a solid clinical evidence base behind it.
Blue light works best on active breakouts and persistently congested skin. It's not a replacement for a consistent skincare routine, but used two or three times a week alongside the right topicals, most people with acne-prone skin notice a real reduction in the frequency and severity of breakouts within four to six weeks.
Red light — 633nm — for collagen, firmness, and lines
Red light penetrates to the dermis — the deeper structural layer of the skin — where it stimulates fibroblast activity and encourages the production of collagen and elastin. This is the wavelength with the longest clinical track record in LED therapy, and the research on it for anti-ageing applications is extensive.
Results from red light are gradual rather than immediate. Collagen remodelling happens over weeks and months, not sessions. But used consistently — three to five times a week — most people notice improved skin firmness, a reduction in the appearance of fine lines, and a general improvement in skin quality and resilience after six to eight weeks. It's one of the most worthwhile wavelengths to build into a regular routine.
Near-infrared light — 830nm — for repair and inflammation
Near-infrared isn't visible to the eye, but it penetrates deeper into tissue than any other wavelength the PRO mask uses. At 830nm it supports cellular energy production (via cytochrome c oxidase in the mitochondria), reduces inflammatory signalling, and accelerates tissue repair.
This is the wavelength to reach for when skin is recovering — after a course of actives, after sun exposure, when it looks dull and stressed rather than just tired. It's also worth using alongside red light in the same session; the two wavelengths work well together and the PRO mask allows you to combine them.
Green light — 520–560nm — for pigmentation and uneven tone
Green light targets melanocytes — the cells responsible for melanin production — and helps regulate pigmentation at the source. It's particularly useful for post-inflammatory hyperpigmentation (the marks left after breakouts), sun spots, and general unevenness of skin tone.
The effects are cumulative and work best alongside SPF during the day. Green light slows down excess melanin production; SPF prevents new pigmentation from forming. Using one without the other reduces what you're able to achieve. Consistent use over eight to twelve weeks tends to produce a meaningful improvement in overall skin evenness.
Yellow light — 590nm — for sensitivity and redness
Yellow light works at a shallower depth than red and is particularly effective for vascular concerns — visible redness, flushing, and rosacea-prone skin. It has a calming effect on the skin's inflammatory response and helps reduce the appearance of diffuse redness over time.
If your skin regularly looks reactive after cleansing or responds strongly to temperature changes, yellow light is worth prioritising in your rotation. It's gentle enough to use when skin is at its most sensitised, and it tends to produce visible results — in terms of reduced redness and a more even complexion — relatively quickly compared to some of the other wavelengths.
How to rotate them across the week
The advantage of a full-spectrum device like the Déesse PRO LED Mask is that you're not locked into treating one concern. A practical approach for most people is to lead with the wavelength that addresses your primary concern — if it's anti-ageing, red light most sessions; if it's pigmentation, green light most sessions — and then bring in the others two or three times a week to support overall skin health. Near-infrared can be paired with almost any other wavelength in the same session, as it works at a different depth and on different cellular mechanisms.
The key is consistency. Any of these wavelengths will produce limited results if used sporadically. Used regularly, they work — the clinical evidence isn't ambiguous on that.
