Light-emitting diode phototherapy at 630 +/- 3 nm increases local levels of skin-homing T-cells in human subjects.

What the authors concluded

Transmission electron microscopy revealed mild fibroplastic changes in fibroblasts, with no acute inflammatory changes throughout the treatment session. Qualitative PCR showed the presence of both Th-1 and Th-2 T-cells, and quantitative PCR showed an increase in the numbers of both types of skin-homing T-cells, much more so for Th-2 than for Th-1." "Visible red LED irradiation appears to activat

Devices that emit this wavelength

Matched on wavelength within 15nm, since LED bins vary by roughly that much and a tighter match would be false precision. Where we have an irradiance figure, the session length is the time needed to reach this study's dose of 94 J/cm² at that intensity.

Matching a wavelength is not the same as reproducing a trial. Session times assume the device's published irradiance is accurate at the distance it was measured, which on brand-claim figures is often optimistic. Where a device publishes both a peak and an average we use the average, and where it publishes a falloff curve we use the lowest figure, so these times run long rather than short. Clinical protocols also control for spot size, contact and skin type in ways a home device cannot.