Light Therapy and Acne: The Research

Light-emitting diode (LED) devices that emit red and/or blue light are widely marketed for acne-prone skin. This article summarizes what major systematic reviews, meta-analyses, and a professional clinical guideline have reported about light therapy and acne. It does not evaluate any individual's skin and is not a substitute for advice from a qualified healthcare professional.

How the research is organized

Studies of light and acne fall into a few broad groups:

• LED light alone — red light, blue light, or both, delivered without any added medication.
• Photodynamic therapy (PDT) — a light-sensitizing compound such as aminolevulinic acid (ALA) or methyl aminolevulinate (MAL) is applied to the skin and then activated with light. PDT is performed in clinical settings and is a different intervention from at-home LED use.
• Other light and laser devices — intense pulsed light, broadband light, and lasers, which are outside the scope of most consumer devices.

Because these interventions differ, results from one group should not be assumed to apply to another.

What the major reviews found

Cochrane systematic review (2016)

A Cochrane review included 71 randomized controlled trials with 4,211 participants. The authors noted that most studies were small (median of 31 participants), that two-thirds were industry-sponsored, and that fewer than half assessed outcomes more than eight weeks after the final treatment. They concluded that "high-quality evidence on the use of light therapies for people with acne is lacking."¹

For red-light MAL-PDT, the review found little or no difference in inflamed lesion counts compared with placebo cream plus red light (moderate-certainty evidence). Certainty for global improvement and for adverse effects across light therapies was rated very low.¹

Systematic review of LED trials in dermatology (2018)

A review of 31 randomized controlled trials of LED devices across several skin conditions assigned acne vulgaris a grade B recommendation, meaning the supporting evidence was considered moderate rather than strong. The authors identified limitations including small sample sizes, lack of blinding, lack of sham controls, and widely varying treatment parameters, and they reported no severe adverse events in the included trials.²

Red light compared with conventional treatments (2021)

A meta-analysis of 13 randomized controlled trials (422 participants) with moderate-to-severe acne compared red light therapy with conventional therapies. It found no statistically significant difference in improvement of inflammatory or non-inflammatory lesions. The authors cautioned that results should be interpreted carefully because of heterogeneity between studies and small sample sizes.³

LED meta-analysis across skin conditions (2023)

A meta-analysis of 31 studies on LEDs for skin conditions reported that red and blue LEDs showed effectiveness for acne vulgaris compared with controls, with low statistical heterogeneity in the pooled acne analysis.⁴

At-home LED devices (2025)

A meta-analysis published in JAMA Dermatology looked specifically at at-home or portable LED devices. It included six randomized trials with 216 participants aged 12 to 50 with mild-to-moderate acne, and study durations ranged from 2 days to 12 weeks. Compared with controls, device groups showed greater percentage reductions in inflammatory lesions, non-inflammatory lesions, and investigator-assessed severity. No severe adverse reactions were reported; minor effects included dryness, redness, and discomfort.⁵

The authors noted moderate-to-high heterogeneity between studies, possible unmeasured publication bias, and uncertainty about whether results generalize to other devices. A published reader letter pointed out that only two of the included trials reported enrolling participants with darker skin types (Fitzpatrick V–VI).⁵

What a professional guideline says

The American Academy of Dermatology's 2024 guidelines of care for acne vulgaris were developed from a systematic review of the evidence. The work group determined that evidence was insufficient to make a recommendation on laser and light-based devices, including photodynamic therapy, and it conditionally recommended against adding pneumatic broadband light to adapalene 0.3% gel.⁶

In other words, while some meta-analyses report favorable results for LED devices, a major professional body reviewing the same broad literature did not find the evidence strong enough to issue a recommendation for light-based acne treatments.

Why the findings appear mixed

The reviews above do not all reach the same conclusion. Their authors point to several recurring reasons:

• Different comparisons. Some studies compare light with no treatment or a sham device; others compare it with established acne treatments. A device can outperform doing nothing without outperforming conventional care.^3,5
• Different interventions. LED-only treatment, PDT, and broadband light are often grouped together in discussion but are distinct.¹
• Varying parameters. Wavelength, irradiance, session length, and treatment schedules differ widely between trials, making results difficult to pool or compare.²
• Small and short studies. Many trials enrolled few participants and followed them for weeks rather than months.^1,2
• Limited diversity. Few trials reported results for people with darker skin types.⁵

Reported side effects in the literature

Across the reviews summarized here, reported adverse effects of LED-only treatment were generally described as mild, such as dryness, redness, or temporary discomfort, and no severe adverse events were reported in the included trials.^2,3,5 The Cochrane review rated the certainty of evidence on adverse effects across all light therapies as very low.¹ Absence of reported harm in small trials is not the same as demonstrated safety for every person or device. For a broader overview, see our article on LED mask safety research.

Summary

Research on light therapy for acne includes dozens of randomized trials, but reviewers consistently describe the overall evidence as limited by small sample sizes, short follow-up, and inconsistent methods. Recent meta-analyses report improvements compared with control groups, particularly for at-home red and blue LED devices in mild-to-moderate acne, while an earlier meta-analysis found no significant difference between red light and conventional treatments, and the American Academy of Dermatology's 2024 guideline did not issue a recommendation for light-based devices.

Disclaimer

This article is for general informational purposes only and does not constitute medical, legal, or professional advice. It summarizes published research and is not intended to diagnose, treat, cure, or prevent any condition, or to suggest that any device will produce a particular result. Study findings may not apply to any individual. Regulatory clearance of a device does not guarantee its effectiveness. Redlight Ratings is not a medical provider. Anyone with questions about acne or a skin condition should consult a qualified healthcare professional.

References

1. Barbaric J, Abbott R, Posadzki P, et al. Light therapies for acne. Cochrane Database of Systematic Reviews. 2016;9(9):CD007917. https://pubmed.ncbi.nlm.nih.gov/27670126/
2. Jagdeo J, Austin E, Mamalis A, Wong C, Ho D, Siegel DM. Light-emitting diodes in dermatology: A systematic review of randomized controlled trials. Lasers in Surgery and Medicine. 2018;50(6):613-628. https://pmc.ncbi.nlm.nih.gov/articles/PMC6099480/
3. Wu Y, Deng Y, Huang P. Application of red light therapy for moderate-to-severe acne vulgaris: A systematic review and meta-analysis. Journal of Cosmetic Dermatology. 2021;20(11):3498-3508. https://pubmed.ncbi.nlm.nih.gov/34363730/
4. Ngoc LTN, Moon JY, Lee YC. Utilization of light-emitting diodes for skin therapy: Systematic review and meta-analysis. Photodermatology, Photoimmunology & Photomedicine. 2023;39(4):303-317. https://pubmed.ncbi.nlm.nih.gov/36310510/
5. Ershadi S, Barbieri JS. At-home LED devices for the treatment of acne vulgaris: A systematic review and meta-analysis. JAMA Dermatology. 2025;161(5):552-555. https://doi.org/10.1001/jamadermatol.2025.0019
6. Reynolds RV, Yeung H, Cheng CE, et al. Guidelines of care for the management of acne vulgaris. Journal of the American Academy of Dermatology. 2024;90(5):1006.e1-1006.e30. https://doi.org/10.1016/j.jaad.2023.12.017