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What are the differences between UVA, UVB, and UVC light?

There are three types of UV light, and each impacts the human body in a unique way.

UVA

UVA light (315nm to 400nm) has the longest ultraviolet wavelength and accounts for the majority of UV light that reaches Earth’s surface. Approximately 95% of the sun’s UV rays are UVA. This is the wavelength that is associated with premature aging, wrinkles, and skin cancer, as it penetrates deep into the dermis layers of the skin. Tanning beds are primarily designed to emit UVA wavelengths to trigger melanin production, which darkens the skin.

UVB

UVB light (280nm to 315nm) is mostly absorbed by the Earth's ozone layer, and of the UV radiation that reaches the Earth's surface, only about 5% is UVB. The intensity at which UVB exposure occurs is dependent on season, geography, and time of day, among other factors. UVB light has more energy than UVA light but only penetrates the outer layers of the skin, the epidermis. UVB light triggers biological benefits such as the production of hormones and neurotransmitters, including vitamin D, but is also the portion of the UV spectrum known to cause sunburn.

Solius delivers more UVB benefit than natural sun with significantly less risk by delivering UVB light in a highly controlled, consistent, and measured way.

Solius targets a narrow peak at 293nm in the UVB spectrum to isolate the wavelengths most responsible for beneficial effects while eliminating nearly all other UV radiation. Before your first session, the Solius app gathers information about your skin history and the device's integrated sensor measures your skin directly. Using this data, Solius calculates a conservative starting dose, around 40% of your estimated maximum safe exposure. After each session, your dose continues to be adjusted based on your skin's response. If you report prolonged redness or irritation, your dose is automatically reduced to prevent overexposure.

​​These safeguards allow Solius to provide UVB benefits while minimizing risk of burns.

UVC

UVC light (100nm to 280nm) has the shortest wavelength in the UV spectrum and most energy. It is the most damaging type of UV light to biological tissue. Exposure to UVC light is mostly avoidable, as this spectrum is almost completely absorbed by Earth’s atmosphere. However, it is produced artificially and widely used for germicidal purposes such as killing bacteria, viruses, and mold, in hospitals, water treatment, and air purification systems.