Not all clothing provides adequate sun protection and people are routinely exposed to the sun’s harmful rays through their regular clothing. The average white cotton T-shirt only provides a UPF rating of 5-7 when dry and about UPF 3 when wet. This allows about 1 out of 3 UVA/UVB rays to penetrate your skin and leaves you unprotected against sun damage. 

The higher the UPF rating, the greater the sun protection. 

Factors that enhance UPF performance: 

• Construction: A dense, tight construction of the fabric will block more UV light 
• Color: Darker, more saturated colors provide more protection than light, paler colors. 
• Treatments: Chemicals UV filters can be added to fabrics to enhance their protective qualities 
• Fiber type: Polyester and nylon are highly effective at blocking UV light, while cotton is minimally effective

Factors that reduce UPF performance:

• Fabric wetness: Wetness can reduce a fabric's UPF performance, especially for textiles made of natural fibers. 
• Fabric wear: The UPF rating of worn or faded pieces can diminish over time
• Fabric stretch: Fabric that is overly stretched will undermine its UPF performance. 

Garment care and its impact on UPF performance. Can UPF properties wash out?

UPF properties can be achieved in a fabric in two ways: inherent or chemical. Inherent UPF means that the structural properties of the fabric ie. the way the yarn is knit or woven together, provides protection from the sun and blocks the harmful UVA/UVB rays from reaching the skin. So long as the integrity of the fabric is maintained and it doesn’t have tears or holes in it, the protective quality of the fabric can’t wash out. 

Chemical UPF is when a fabric is treated with a topical chemical UV filter (similar to sunscreen). Chemical UV filters may degrade over time with continued washing and/or exposure to the sun. As with inherent UPF, chemical UPF fabrics that are overly stretched or develop holes will no longer provide sun protection in those areas. 

Follow care instructions to prolong and maximize the life of the apparel. As with all products, the effectiveness of the apparel may degrade over time. 

Two types of UV light are proven to contribute to the risk for skin cancer and have harmful impacts on the skin:

• Ultraviolet A (UVA) has a longer wavelength. It is associated with skin aging.
• Ultraviolet B (UVB) has a shorter wavelength. It is associated with skin burning.

UVA (aging) rays penetrate deep into the dermis, the skin’s thickest layer, and are primarily responsible for premature skin aging, which can take the form of  wrinkles, dark/age spots, dryness, hyperpigmentation, loss of skin tone, loss of skin texture, loss of collagen and sagging. These rays maintain the same level of strength during daylight hours throughout the year and can penetrate windows and cloud cover. 

UVB (burning) rays penetrate and damage the outermost layers of your skin. Overexposure causes sunburns and, in severe cases, blistering. UVB intensity fluctuates: while the sun’s rays are strongest and pose the highest risk late-morning to mid-afternoon from spring to fall in temperate climates and even greater time spans in tropical climates, UVB rays can damage your skin year-round, especially at high altitudes or on reflective surfaces like snow or ice.

The information available on this website, including but not limited to information regarding UVA and UVB Rays and UPF, is general in nature; it is not intended as medical advice or a substitute for obtaining medical advice. Claudent makes no representation and assumes no responsibility for the accuracy of information contained on, or available through, this website, or its suitability for any purpose, and such information is subject to change without notice. This website, all of the information it contains, and all Claudent products are provided "as is" without any express or implied warranty. All implied warranties, including, without limitation, implied warranties of merchantability, fitness for a particular purpose, and non-infringement, are hereby expressly disclaimed. You are encouraged to confirm any information obtained from or through this website with other sources, and review all information regarding sun protection with your physician. Never disregard professional medical advice or delay seeking medical treatment because of something you have read on, or accessed through, this website.