Can red light therapy penetrate clothing?
A frequently asked practical question is whether you can use a red light therapy device while wearing clothes. The short answer: the amount of light reaching the treated surface can change when wearing clothes. Therefore, you cannot simply assume that a session through clothing is the same as a session where the light falls directly on the skin.
Why does clothing make a difference?
A fabric can block, scatter, or reflect part of the light. How much is transmitted depends on, among other things, the material, thickness, color, texture, and how closely the fabric fits the skin. Therefore, there is no universal rule such as: "red light therapy always works through clothing."
Wavelength is just one component
In red light therapy, you encounter, for example, 660nm red light and 830nm or 850nm near-infrared light. The wavelength is important but does not solely determine how much light the skin receives. Irradiance, distance, treatment time, device, and usage protocol also play a role.
What is practically the best approach?
- Always follow the manual of the specific device.
- If the manufacturer prescribes application to bare skin, use the device accordingly.
- If you wish to treat through clothing, check if the manufacturer explicitly supports this.
- Do not independently change the treatment time to compensate for potential light loss due to clothing.
Why direct application to the skin is often clearer
When a device is designed for direct skin exposure, you have a better understanding of the conditions associated with the specified usage protocol. This makes your routine more reproducible than if you try to estimate how much light passes through a particular fabric yourself.
Frequently asked questions
Can red light therapy penetrate a thin shirt?
Some light can pass through certain fabrics, but the amount varies greatly. Without specific information from the manufacturer, you cannot reliably determine the dose the skin receives.
Is red light therapy through clothing the same as on bare skin?
No, not necessarily. Clothing can alter light exposure.
Should I treat longer if I'm wearing clothes?
Not automatically. Follow the prescribed protocol of the device instead of increasing the treatment time yourself.
Where can I find more information about 660nm and 850nm?
See the Red Light Therapy FAQ and the Red Light Therapy Knowledge Center for more explanation on wavelengths, dosage, and device selection.
Conclusion
The safest and most reliable approach is simple: treat as the manufacturer has designed and prescribed for the specific device. Clothing can affect the amount of light reaching the skin, meaning a session through clothing is not automatically equivalent to direct skin exposure.