SPF vs UPF – What Offers More Sun Protection?

Written by Sara Wilchowski, PA-C
Edited by Paul M. Graham, DO

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As many of us get ready to enjoy the summer sun, we feel that this article will serve you well to prevent unwanted, damaging sunburn. Most people are aware that the suns rays are harmful but a lesser known fact is that 1 in 5 Americans will be diagnosed with skin cancer during their lifetime. The sunscreen used currently to protect ourselves can be messy, greasy, cause allergic reactions, and of course, you need to apply the correct amount and reapply often. What else can you do to protect yourself? The answer is simple and easy: Cover up with sun-protective clothing! 

A relatively new classification for sun-protective clothing is defined using the abbreviation UPF (Ultraviolet Protection Factor). UPF is measured as the ratio of UV-causing sunburn both with and without UPF protective fabric.  

With UPF clothing, hats, and umbrellas you do not have to worry about all the greasy goop! The advantages are vast. There is no need to wait for it to work, once it’s on it’s working! Unlike sunscreen, it doesn’t degrade or break down after 2 hours. Additionally, it’s not greasy, not allergenic, long-lasting, fashionable, and less expensive over the long term. Welcome to the next generation of sun protection!

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SPF (Sun Protective Factor)

The SPF value is a measure of the fraction of ultraviolet rays that are able to reach the skin after sunscreen application. For example, an SPF 15 translates to transmission of 1/15th of the ultraviolet rays reaching the skin, assuming that the recommended 2mg/cm2 of sunscreen is applied. An amount consisting of 2mg/cm2 correlates to a golfball size amount per area (enough to fill a shot glass). In simpler terms, you may be able to figure out a rough estimate of how much time you have in the sun before a sunburn develops. To do this, you first need to know on average how long it takes for your skin to develop a sunburn without the use of sunscreen. For example, if it takes 10 minutes (mean erythema dose) in the sun for you to develop a sunburn on unprotected skin, then you take the SPF value of the sunscreen and multiply it by 10. 

Example: SPF 15 x 10 minutes (sunburn time) = 150 minutes before a sunburn typically develops 

Check out Sarah’s video review of Coola sunscreens HERE

In 2011 the FDA banned the terms waterproof, sweatproof, and sunblock. Sunscreen also typically losses its effectiveness after 2 hours from the initial application as the chemicals break down and the particles disperse. A term approved by the FDA that is commonly seen on sunscreen bottles is water resistant, meaning that it can stay on the skin when immersed in water for either 40 or 80 minutes. This means you need to reapply your sunscreen often especially if you are swimming or sweating as the particles are washed off the skin surface after a certain amount of time!  

1ae95b077d0c1cd56e1cd564947924c9.jpgNow that we have covered the meaning of SPF, what is UPF?  Ultraviolet protective factor, or UPF, relates to the total amount of UVA and UVB blocked by an article of clothing or fabric (1).  This was first developed in 1996 in Australia, where skin cancer rates are the highest in the world. The term UPF reflects the number of UV rays that penetrate the garment and reach the skin. An article of clothing that has a UPF 50 will only allow approximately 1/50th of the suns rays to reach the skin. UPF protects against both UVA and UVB rays and offers comprehensive protection than SPF alone (2). Just as sunscreen is regulated by the FDA, so is UPF clothing. The American Association of Textile Chemists and Colorists put each UPF garment through a series of four tests assessing its ability to block UV rays. A thin white cotton T-shirt, which has a UPF of approximately 5, allows 1/5th of the sun’s UV rays to pass through—even when wet (2). Interestingly, jeans have a UPF of 1700, but no one is going to be walking around on the beach in a jean one piece! (although you can’t get much better protection than that!) No garment can be labeled as being “sun protective” if the UPF rating is less than 15, however, the Skin Cancer Foundation recommends a UPF of at least 30 (2).  

What are the benefits of UPF clothing?  

  • Easy application

  • No need to reapply

  • Non-greasy feel

  • Fashionable

  • No expiration date

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There are many key factors that play a role in determining the UPF of specific clothing. Just because you can hold the shirt up and cannot see visible light passing through, does not mean that UV radiation, which is not seen by the naked eye, is blocked.  Factors that affect how the garment is rated include:
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  1. Weave Density – How tight the fabric fibers are bound together and how much open space exists between fibers.

  2. Color – Darker colors absorb more UV radiation than lighter colors.

  3. Moisture Content – Most fabrics have a lower rating when wet.

  4. Fabric Condition – More washing or frayed the fabric, the more UV radiation will penetrate through the clothing.

Don’t want to buy new clothes? There is another option, you can dye the clothing you already have. Rit SunGuard is currently the only dye that can be used on clothing to enhance the UPF  by using a product called Tinosorb FD. This product allows a typical shirt to increase the UPF to 30. This chemical acts as an invisible dye that penetrates the clothing fibers without changing the texture of the fabric (1).  However, there is a downside as these dyes are only temporary and will wash out after approximately 20 washes. 

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Examples of UPF clothing:

There are many things that you can do to protect yourself from the sun’s damaging UV rays. Make sure to check out our other articles on sun protection for more information!

Anti-Aging Secrets: The Daily Skincare Routine
Sun Protection: The Burning Truth
How Effective Is Your Sunscreen?
SPF: What does it really mean?
Beware Of A Base Tan
Sunburn: What Can I Do?
Heliocare: A Sun Protection Pill
Sunscreen: Your Skin’s Bodyguard

References:

  1. Edlich, R. et al.  Revolutionary Advances in Sun-Protective Clothing – An Essential Step in Eliminating Skin Cancer in our World.  Journal of Long-Term Effects of Medical Implants, 14(2)95-105 (2004)
  2. Skin Cancer Foundation. “Everyday and High-UPF Sun-Protective Clothing” -SkinCancer.org. N.p., n.d. Web. 27 July 2017.

Please note, our medical disclaimer applies to all information, images, recommendations, and comments published on this page.

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