Yes, you can tan through a white shirt because ultraviolet (UV) rays, which cause tanning and sunburn, can pass through fabric.
Understanding How Tanning Works Through Clothing
Tanning is the skin's response to exposure to ultraviolet (UV) radiation. When UV rays reach your skin, they stimulate the production of melanin, the pigment that gives skin its color. While clothing offers some protection against UV radiation, it doesn't block 100% of these rays.
UV Penetration Through Fabric
It's possible for UV rays to pass through clothing and reach the skin. The degree to which UV rays penetrate fabric depends on several factors:
- Fabric Type: Densely woven materials like denim or polyester offer better protection than loosely woven fabrics like cotton or linen.
- Color: Darker colors tend to absorb more UV radiation than lighter colors, meaning less reaches your skin.
- Wetness: Wet fabric typically allows more UV rays to pass through than dry fabric.
The Case of a White Shirt
A regular white cotton t-shirt is often made from a relatively loose weave and is a light color. This combination means it offers limited protection against UV rays.
In fact, a regular white cotton t-shirt may only provide a UPF rating of 5 – that means roughly 20% of UV radiation passes through the fabric and penetrates your skin.
A UPF (Ultraviolet Protection Factor) rating indicates how much UV radiation a fabric blocks. A UPF of 5 means the fabric blocks about 80% of UV radiation, allowing about 20% to pass through. While 80% protection is better than nothing, the 20% that passes through is sufficient to cause tanning or even sunburn over time, especially during peak sun hours or extended exposure.
Practical Implications
- Partial Protection: A white shirt offers some protection compared to bare skin, but it's not a complete shield against the sun's rays.
- Tanning Risk: You can still get a tan, or even sunburn, on areas covered by a white shirt if exposed for a significant period.
- Enhanced Protection: For better sun protection from clothing, look for garments with a high UPF rating (e.g., UPF 30 or 50+), which are often specifically designed to block UV rays and may use different fabrics, weaves, or dyes.
Wearing a white shirt can reduce your UV exposure compared to wearing nothing, but it does not eliminate the risk of tanning or sun damage.
