Standard red light therapy is not a source of ultraviolet (UV) rays. It uses visible red light, usually around 620 to 700 nanometers (nm), and may also use near-infrared light at longer wavelengths. UV radiation occupies the shorter 100 to 400 nm range.
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Red Light Therapy vs. UV Light
| Type of light | Typical wavelength | Visible? | Main concern |
|---|---|---|---|
| UVA | 315 to 400 nm | No | Skin aging and DNA damage |
| UVB | 280 to 315 nm | No | Sunburn and skin cancer risk |
| Red light therapy | About 620 to 700 nm | Yes | Bright-light and eye-exposure concerns |
| Near-infrared therapy | Usually above 700 nm | No | Heat, eye exposure and device-specific risks |
UV radiation can damage the skin and contribute to skin cancer. Red light therapy uses much longer wavelengths. Current research has not found that red light causes skin cancer in the same way UV exposure can.
Does Red Light Therapy Cause Sunburn or Tanning?
No. Red light therapy does not normally cause UV-related sunburn or tanning. Sunburn and conventional tanning are linked to ultraviolet exposure, especially UVB and UVA. A red light therapy device that uses the stated red or near-infrared wavelengths does not use those forms of UV light.
Red light can affect the skin in other ways. The American Academy of Dermatology notes that some people, particularly those with darker skin tones, may experience pigmentation changes from visible light. That is different from UV damage, but it is still a reason to follow the device instructions and speak with a dermatologist if you are prone to hyperpigmentation.
Can a Red Light Therapy Device Emit UV Light?
A red or red-and-near-infrared LED device should not intentionally emit UV light. However, products marketed as "light therapy" do not all use the same wavelengths.
Check the product specifications for:
- Red wavelengths such as 630 nm, 633 nm or 660 nm
- Near-infrared wavelengths such as 810 nm, 830 nm or 850 nm
- A clearly stated wavelength range
- No mention of UVA, UVB, UVC, tanning or ultraviolet treatment
Some LED devices combine red light with blue light for acne treatment. Blue light around 415 nm is visible light, not UV, although it is a different treatment wavelength. FDA-cleared device documentation commonly lists red, blue and near-infrared wavelengths separately.
Do not assume a product is UV-free when the manufacturer has not published its wavelengths.
Is Red Light Therapy Safe for the Eyes?
UV-free does not mean risk-free for the eyes. Bright LEDs and near-infrared light can cause discomfort or injury when used incorrectly. The FDA warns that light-based procedures can injure the eyes. The American Academy of Dermatology recommends wearing the supplied eye protection whenever the device instructions require it.
Use a red light therapy device more safely by:
- Following the manufacturer's instructions for exposure time and distance.
- Wearing the recommended protective goggles.
- Not staring directly into high-powered LEDs.
- Avoiding devices with no published wavelength information.
- Asking a doctor before use if you take photosensitising medication or have a light-sensitive condition.
Key Takeaway
Check the wavelength information before using a light therapy device. Follow its exposure and eye-protection instructions, and avoid products whose specifications are unclear.