green light (532 nm) penetrates skin layers with measurable depth and intensity
In photodynamic therapy, light at 532 nm penetrates skin with depth-dependent attenuation: 59% of incident irradiance is preserved at the dermal-epidermal junction, dropping to 25% after passing through papillary dermis microvasculature due to strong hemoglobin absorption, and reaching only 20% at 191 μm depth.
What this means for you
Understanding how light moves through skin helps explain why certain wavelengths reach the living layers where cellular activity actually happens. Green light at 532 nm retains meaningful intensity through the upper dermis — the zone where collagen, circulation, and skin renewal are most active — which is why light-based wellness approaches target specific depths for specific effects.
The published research
Computational modeling of oxygen dynamics in port-wine stain photodynamic therapy: treatment outcome optimization and pain management
Journal of Biomedical Optics · 2026
This page describes a documented finding about the underlying wellness technology. It is not a marketing claim about any specific device. For information about HOCATT specifically, visit hocatt.com.