Red light therapy and skin conditions: what the evidence shows beyond acne and wrinkles

Rosacea is a chronic inflammatory skin condition characterised by persistent facial redness, visible blood vessels (telangiectasia), and in some subtypes papules and pustules. It is primarily a vascular and inflammatory condition - driven by neurovascular dysregulation, immune signalling, and in some cases Demodex mite overpopulation - which maps well onto two of PBM's most established mechanisms.

A 2025 review published in Lasers in Medical Science specifically asked whether photobiomodulation could be used for rosacea treatment (Boaretto Netto et al.). Reviewing clinical and experimental studies, the authors concluded that PBM has the potential to decrease rosacea hallmarks by reducing pro-inflammatory factor expression, modulating immune cell activity, and promoting extracellular matrix remodelling. The review noted that red and near-infrared wavelengths act on the same NF-kB inflammatory pathway - the molecular switch driving chronic skin inflammation - that is consistently dysregulated in rosacea. The authors were clear that the available clinical evidence base is limited and that further RCTs are needed before firm treatment recommendations can be made.

At the clinical level, existing studies are small in scale. A case series published in the Journal of Medical Case Reports (Sorbellini et al. 2020) reported positive responses in two rosacea patients treated with combined blue and red LED phototherapy, describing it as an effective and well-tolerated approach. A larger clinical observation published in Lasers in Medical Science (2025, PMC12513978) examined LED light therapy alongside IPL and hydroxychloroquine in 90 rosacea patients, finding LED to be a viable lower-cost option with a favourable tolerability profile. The larger systematic review of LED RCTs by Jagdeo et al. (2018) did not identify RCTs specifically for rosacea with statistical results, underscoring that the evidence base remains preliminary rather than definitive.

Hyperpigmentation covers a range of conditions where excess melanin production creates darker patches or uneven skin tone. Melasma, post-inflammatory hyperpigmentation (PIH) after acne or injury, and sun-induced lentigines (age spots) all involve overactive melanocytes - the cells responsible for producing melanin. Conventional treatments - hydroquinone, chemical peels, lasers, kojic acid - are effective but can be harsh, and some carry a risk of triggering further hyperpigmentation through irritation, particularly in darker skin types.

The mechanism by which PBM may address hyperpigmentation operates differently from most other skin applications. A 2024 integrative review by Galache et al. (Photodermatology, Photoimmunology and Photomedicine) identified nine relevant clinical studies and concluded that PBM can reduce melasma-associated hyperpigmentation. Specific wavelengths including red (630 nm) and NIR (830-940 nm) were found to exert modulatory effects on tyrosinase activity (the enzyme that drives melanin production) and on gene expression in melanocytes. In vitro studies have shown that NIR wavelengths at 830 nm, 850 nm, and 940 nm can inhibit melanin biosynthesis by targeting the intracellular signalling pathway, including effects on tyrosinase-related proteins, without cytotoxic effects on normal melanocytes.

The most direct clinical evidence comes from a split-face pilot study by Barolet (J Clin Aesthet Dermatol, 2018, PMID 29657669) in seven patients with bilateral dermal melasma that had proved resistant to previous treatments. Using pulsed 940 nm photobiomodulation for eight weekly sessions, the treated side showed statistically significant improvement in Melasma Area and Severity Index scores at week 12 compared to the untreated control side (p<0.001). The authors also noted a secondary finding: the treated skin appeared to build resistance to further UV-induced pigmentation.

Psoriasis is an immune-mediated inflammatory skin condition characterised by the overproduction and rapid accumulation of skin cells, producing the raised, scaly plaques that define the condition. Conventional phototherapy for psoriasis - primarily narrowband UVB - is an established treatment, but it uses UV light, carries long-term cumulative risk, and requires clinical administration. Red and near-infrared LED phototherapy operates on a different mechanism and does not carry the UV damage risk.

A preliminary clinical study by Ablon (Photomedicine and Laser Surgery, 2010, PMID 19764893) enrolled nine patients with chronic, recalcitrant psoriasis - cases that had proved resistant to conventional treatments. Treating with combined 830 nm NIR (60 J/cm²) and 633 nm red (126 J/cm²) LED phototherapy over 4-5 weeks, clearance rates by the end of follow-up ranged from 60% to 100%, with patient satisfaction described as universally high. The study's significant limitation is its small size and lack of a control group, meaning it provides preliminary signal rather than confirmed efficacy.

The more rigorous evidence comes from the systematic review of LED RCTs by Jagdeo et al. (2018), which identified three double-blind, split-body RCTs on LED therapy for psoriasis. Two of those three RCTs used blue light (420-453 nm) and both showed significant improvement in local psoriasis severity index compared to the contralateral untreated control plaques after four weeks of daily treatment. A third RCT using combined blue and red LED also showed improvement, though the effect appeared to be concentrated on the inflammatory component of the plaques rather than on their hyperproliferative thickness. One distinction matters here: the RCT evidence is primarily for blue light wavelengths; the red and NIR wavelengths most relevant to full-body panels are best evidenced through the Ablon study and the mechanistic anti-inflammatory pathway, rather than controlled trials specifically testing those wavelengths in psoriasis. Lesions recurred following treatment cessation in one study - a pattern consistent with the chronic nature of psoriasis rather than a specific failure of the therapy.

Atopic dermatitis - the most common form of eczema - is a chronic inflammatory skin condition characterised by barrier impairment, intense itching, and recurrent inflammatory flares. The skin barrier in atopic dermatitis is structurally compromised, often related to filaggrin protein deficiency, which allows irritants and allergens in and lets moisture out. The immune response is dysregulated, with Th2-type inflammation driving the characteristic symptoms.

Of the six conditions covered in this blog, eczema has the most limited direct clinical evidence for red and NIR light specifically. The systematic review and meta-analysis by Ngoc et al. (Photodermatology, Photoimmunology and Photomedicine, 2023) is the most comprehensive assessment available. Reviewing 31 LED RCTs across multiple dermatological conditions, the authors found seven studies on atopic dermatitis. While individual clinical studies reported beneficial effects on eczema symptoms including itching, redness, and lesion severity, these effects did not reach statistical significance when pooled in meta-analysis. The authors concluded that further, larger studies are required.

The most relevant single RCT identified in the Jagdeo 2018 systematic review used blue light (453 nm, 90 J/cm²) three times weekly for four weeks in 21 patients with atopic dermatitis, reporting a 30.4% improvement in eczema severity index compared to the control. This is blue light rather than red or NIR, and the study size is small. For red and NIR light specifically, the mechanistic case for eczema is credible - PBM's anti-inflammatory effects, barrier repair properties, and reduction in oxidative stress are all potentially relevant - but the direct clinical trial data is thin and does not yet support the same confidence as for scarring or wound healing.

Scar remodelling is one of the better-evidenced applications of PBM in dermatology, with a clearer mechanistic basis and more controlled clinical data than most of the other conditions in this blog. The key distinction is that scar tissue management involves reorganising existing collagen rather than producing new collagen from scratch - a meaningfully different biological process from the anti-ageing mechanisms discussed in the wrinkles blog.

When a wound heals, collagen fibres are laid down quickly and in a disorganised pattern, producing the raised, firm, or discoloured texture of scar tissue. Remodelling that scar - softening it, flattening it, normalising its colour - requires regulated breakdown and reconstruction of the collagen matrix, which is governed by matrix metalloproteinases (MMPs). PBM at 630-660 nm has been shown to modulate TGF-beta signalling and MMP activity in fibroblasts, shifting the remodelling balance in favour of a more organised, less fibrotic outcome.

The most methodologically sound clinical evidence comes from the CURES trial (Cutaneous Understanding of Red-light Efficacy on Scarring), a randomised, mock-controlled, split-face phase II clinical trial published in the Journal of Biophotonics (Kurtti et al. 2021, PMID 33788987). Starting one week after surgery, patients had LED red light applied to incision sites at different fluences, with the opposite side of the face receiving mock therapy as a control. At six months, the medium-dose treated scars showed a 77.8% decrease in induration (firmness) from baseline, compared to 50% in the untreated control scars. The split-face design is important because it eliminates inter-individual differences in healing, allowing within-patient comparison.

The CURES trial is supported by a body of in vitro work from the same research group at SUNY Downstate, showing that LED red light inhibits keloid fibroblast proliferation, modulates TGF-beta pathway activity in human skin fibroblasts, and reduces characteristics associated with skin fibrosis. The JAAD expert consensus paper (2025), based on a systematic literature review and Delphi process involving 21 dermatology specialists, listed scar management as one of PBM's established clinical applications.

Wound healing was one of the first clinical applications identified for photobiomodulation - dating to Mester's 1967 observations of accelerated healing in mice - and it remains one of the most studied and consistently supported. It is relevant here in two distinct contexts: general wound and skin repair following injury or procedure, and the growing use of PBM as a complementary support after dermatological procedures such as laser resurfacing, chemical peels, or microneedling.

The JAAD expert consensus paper (2025) - based on a systematic literature review and a Delphi process with 21 dermatology specialists - explicitly listed wound ulcers due to multiple etiologies and decubitus ulcers as established effective applications of PBM. The systematic review and meta-analysis by Ngoc et al. (2023), covering 31 LED RCTs, found that LED phototherapy reduced wound healing time by stimulating collagen production, fibroblast proliferation, and cellular metabolism, and reduced reactive oxygen species through its anti-inflammatory effects. Red LED and NIR LED were shown to activate fibroblast growth factor and other repair signals.

The proposed mechanism is the most direct of all six conditions in this blog. Photon absorption by cytochrome c oxidase increases ATP production and improves the cellular energy environment in compromised tissue. This directly supports the energy-intensive processes of wound repair: fibroblast migration and proliferation, collagen synthesis, keratinocyte regeneration, and angiogenesis (new blood vessel formation to supply healing tissue). In damaged or hypoxic cells - which are exactly the cells present at a wound site - PBM's stimulatory effect on cytochrome c oxidase is most pronounced, consistent with the biphasic dose response that characterises PBM generally.

Post-procedure use deserves specific mention. Dermatologists increasingly combine red and NIR LED phototherapy with ablative or non-ablative procedures - laser resurfacing, microneedling, chemical peels - as a recovery support tool. This application is mechanistically well-grounded: the wound created by a procedure is precisely the environment in which PBM's cellular repair effects are most relevant. Several published protocols describe this combination approach, with the general recommendation to apply LED therapy immediately following or within 24 hours of the procedure, and then at intervals during the healing phase.