If you’ve ever wondered about the safety of phototherapy—especially when it comes to skin heating or compatibility with different pigmentations—you’re not alone. For years, phototherapy has been celebrated for its photochemical and photophysical benefits, not thermal effects. But recent reports of skin warming in dark-pigmented skin with single-wavelength low-level laser therapy (LLLT) have raised valid questions. Today, we’re diving into a groundbreaking study that sets the record straight: combined super-pulsed lasers and red/infrared LEDs are safe, non-thermal, and effective for all skin tones.
The Study: What Did Researchers Investigate?
Published in Lasers in Medical Science in 2015, this study aimed to solve a critical gap: understanding the thermal impact of concurrent phototherapy (super-pulsed lasers + LEDs) across light, medium, and dark skin pigmentations. Prior research had flagged temperature increases in dark skin with 810nm and 904nm single-wavelength lasers—even at doses within WALT (World Association of Laser Therapy) guidelines. But what happens when multiple wavelengths and light sources are used together, as in clinical practice?
Led by a team from Nove de Julho University (Brazil) and researchers across institutions, the study recruited 42 healthy volunteers (18+) with diverse skin tones, stratified using Von Luschan’s chromatic scale (a gold standard for measuring skin pigmentation). The team used a state-of-the-art multi-diode device (Multi Radiance Medical™) featuring:
- 4x 905nm super-pulsed laser diodes (250 Hz)
- 4x 875nm infrared LEDs
- 4x 640nm red LEDs
Each participant received four treatments: a placebo (0 J, 60s), 10 J (76s), 30 J (228s), and 50 J (380s)—doses commonly used in clinical settings. Skin temperature was monitored with a thermographic camera during the final 5 seconds of irradiation and for 1 minute post-treatment.
Key Findings: No Thermal Risks, Universal Safety
The results were clear and reassuring: no significant skin temperature increases were observed across skin color, age, or gender groups (p > 0.05). Even at the highest dose (50 J), the combined light sources did not cause excessive heating—regardless of whether the participant had light, medium, or dark skin.
This is a game-changer for two reasons:
- Eliminates Pigmentation Concerns: Darker skin tones, which have more melanin (a natural absorber of light), are often considered higher risk for thermal side effects. But this study proves combined super-pulsed lasers and LEDs bypass that risk.
- Confirms Non-Thermal Benefits: The positive outcomes of this phototherapy approach (backed by prior clinical trials) are due to photobiomodulation—the targeted interaction of light with tissue to stimulate healing, reduce inflammation, and boost cellular function—not heat.
Why This Matters for You
Whether you’re a healthcare provider recommending phototherapy or a patient seeking safe, effective treatment, this study offers peace of mind:
- For Clinicians: You can confidently use combined super-pulsed laser/LED devices for all patients, regardless of skin tone, age, or gender. The doses tested (10–50 J) are clinically relevant and safe.
- For Patients: If you have dark skin, you don’t need to worry about thermal damage from this type of phototherapy. The treatment’s benefits—from pain relief to tissue repair—are accessible to everyone.
- For the Industry: This research reinforces that multi-wavelength, multi-source phototherapy is a superior approach to single-wavelength devices, especially when safety across diverse populations is a priority.
The Bottom Line
Phototherapy’s power lies in its ability to trigger natural biological responses without harsh side effects. This study confirms that when using combined super-pulsed lasers and red/infrared LEDs, those benefits are available to every skin tone—no thermal risks, no compromises.
If you’re considering phototherapy for pain management, wound healing, or other conditions, look for devices that combine super-pulsed lasers with red and infrared LEDs. And rest easy knowing: science supports their safety for all.
For the full study, visit: https://pubmed.ncbi.nlm.nih.gov/25987340/