Sun Protective Clothing Explained.

As the owner and co-founder of a sunscreen company I am the first to tell you that clothing is just as important part of sun protection as sunscreens and most of the time more convenient. So, for that reason, as a dermatologist I recommend using sun protective clothing on your body wherever it’s possible and sunscreen in areas where coverage with clothing is difficult. Of course, if you are not sure how protective your clothing is, best to use both for double protection.

Dr. Edit Olasz Harken MD PHD

WHAT ARE THE ADVANTAGES OF SUN PROTECTIVE CLOTHING VS. SUNSCREENS?

People tend to apply less sunscreen than the amount that is used for SPF testing (2mg/cm2); therefore, the achieved protection is usually less than stated on the label1-2. Clothing can provide less protection if it is stretched or weakened by frequent washing but in general it gives the same protection every time when you ware it.

Skipping areas is very common when applying sunscreen and about 10-20% of body surface can remain unprotected1-2. On the face the skin around the eye is the most commonly area that is missed3. Applying sunscreen in two layers significantly decreases the skipped areas and optimizes coverage, one study showed from 20% to 9%2. Clothing gives you even coverage and unless it is not worn properly (like when you pull up your sleeves) and areas can be exposed, you will know that you are protected everywhere.

Sunscreens can be washed off with sweat and water especially if they are not water-resistant and they have to be re-applied. Clothing won’t wear off (unless you take it off) and provide you with lasting protection. Be aware that UV protection of some material can decrease when it becomes wet.

SPF measures only UVB protection and UPF measures both UVB and UVA protection. Why is that important? SPF only focuses on burning and tells you how much longer you can stay out on the sun with the sunscreen before you burn vs. when you don’t wear sunscreen. Those burning sun rays are biggest reason for skin cancer formation, but UVA also contributes to skin cancer and is the main cause of skin aging.

In general, the higher the SPF, the higher the UVA protection and sunscreens with “broad band label” give good UVA protection, BUT two sunscreens with the same SPF still may give you very different UVA protection.

Comfort and convenience. It is no doubt that it easier to slip on clothing and slap on a hat. Have you seen parents trying to apply sunscreen on their little ones, running after the kids with a spray that goes everywhere but not on the skin? As a parent, it’s easier to put UPF clothing on children. Although newer studies show melanoma risk increases with sunburns regardless of age when you sunburned 4, it is our responsibility to protect our children and they should be taught early about the healthy habit of sun protection especially if they have fair skin.

WHAT IS ULTRAVIOLET PROTECTION FACTOR (UPF)?

Ultraviolet protection factor (UPF) is a measure of fabric’s protection against both UVB (burning) and UVA (aging) rays. Because UPF signifies protection against both rays, you can think about it as equivalent of “broad band protection” in the US or SPF/PA protection in Asia and EU. The higher the UPF value, the better is the protection. A clothing with UPF 50 allows 1/50 (2%) of UV rays to reach the skin.

HOW IS UPF MEASURED?

The UPF clothing standards were first established by the Australian/New Zealand authorities in 1995. Just like SPF, UPF is regulated differently in Australia/New Zealand, the European Union and the United States 5. Photoprotective clothing was regulated by the FDA in the 1990s, however this has since stopped in favor of the guidance of other non-government organizations regulating textiles 6.

UPF is measured by testing the average UV exposure to bare skin as compared to fabric-protected skin. UPF is assessed either by an in vitro or in vivo (on people) method 7. UPF rating of 15-29 is classified as “Minimum”, 30-49 is rated as “Good”, UPF of 50 and above is classified as “Excellent”. In Europe, clothing labeled as photoprotective must pass a greater threshold (UPF 40+) and must maintain an average if UVA transmittance of below 5% 8. This is very important for people who have skin conditions that can be aggravated by small amount of UVA such as solar urticaria, chronic actinic dermatitis or melasma.

HOW IS SPF DIFFERENT FROM UPF?

SPF measures only UVB protection and UPF measures both UVB and UVA protection (if measured with the in vivo method). SPF may decrease with time due to sweating, water exposure, rubbing or simple break down of the UV filters (the chemical ones). UPF factor stays stable but may change when the fabric becomes wet.

HOW DOES WATER AFFECT UPF PROTECTION?

Studies show that when clothing becomes wet the UPF factor may change and mainly dependent on the type of fabric 9. For example, linen, viscose and polyester fabrics, UPF significantly increased when saturated with water. Wet cotton fabrics however became less UV protective. Interestingly, it seems that it does not matter whether salt or fresh water making your clothing wet 9.

WHAT PARAMETERS AFFECT UPF?

Several factors will influence your clothing UV protection including fabric type, fabric structure, color, dryness, fit on body, and laundered effect5. In general, the tighter the weave is, the darker the color and the less sun shines through when you put the fabric against the sun, the higher the UPF should be.

Fabric typePolyester: high Wool: moderate Cotton, silk, nylon, rayon and linen: low
Fabric structure: weave, thickness, stretchThe tighter the weave and less porous has more UPF
ColorDarker colors have higher UPF, black, dark blue and dark green is the best. Some dyes contain benzene rings that serve as UV absorber.
DrynessIt depends see above but most fabrics lose UPF when become wet
Fit on the bodyLoose fitting clothing have higher UPF (less stretch)
LaunderedMore laundered fabrics have a higher UPF

WHAT IS THE UPF OF THE CLOTHS I AM WEARING?

It is best to use clothes that are tested to make sure they are really protective but here is an estimate of several fabric types you may use as a guidance5.

Type of clothingUPF
Bleached cotton8-14
Non-bleached cotton10-30
Lined4-14
Silk4-14
Polyester athletic shirts19-49
Denim cotton blue jeans50+

CAN I INCREASE THE UPF OF MY CLOTHING?

You can add UV absorbers by adding those to your laundry. You can either add to your detergent or fabric softener. Most commonly used ingredients are Tinosorb FD (added to detergent) and Tinosorb FR (added to softener) 10. Search for “Laundry treatment UV protectant”.

HOW DO COMPANIES INCREASE UPF IN THEIR CLOTHING?

Because probably you don’t want to wear jeans on the beach, and most natural fabrics don’t have UPF 50, manufacturers often add UV absorbing ingredients to clothing that are formally designed for sun protection and labeled with high SPF. Traditionally, nanoparticles composed of metal oxides such as titanium dioxide and zinc oxide that act as inorganic UV filters can enhance UPF. This technology fades with laundering, newer textile technologies now can make the photoprotection longer lasting. Iron oxide, copper oxide and graphen oxide can also be used as finishing agents for UV clothing. Even more advanced technologies include using carbon nanotubes as finishing agents resulting in UPF above 70. Organic compounds such as benzophenone derivate dyes also increase UPF but given their adverse effects to the marine environment including the reefs and implicated huma health impacts, you should avoid those materials. There are many new naturally occurring plant extracts that are evaluated for their photoprotection boosting capabilities, most have flavonoids or carotenoids as UV filter boosting ingredients5.

CONCLUSION OF PHOTOPROTECTION CLOTHING.

Clothing is the easiest and best way to protect yourself from the harmful effect of the sun. Cover as much body surface areas as possible with clothing, even better, UPF clothing. If you wear normal clothing without specific UPF50+ labeling, it is best to also use sunscreen. UPF clothing is regulated and measured differently across the world and not all UPF labels can be trusted. Supplement photoprotective clothing with diligent use of sunscreen, hats, sunglasses and “sun smart behavior”. Seek shade as much as possible, avoid direct sun exposure between 10 AM and 3 PM and never intentionally tan or lay on the sun. If you have children, teach them early about the importance of sun protection and let them wear UPF clothing so it becomes second nature for the rest of their lives. You remember proper sun protection saves lives!

REFERENCES

1. Jovanovic Z, Schornstein T, Sutor A, Neufang G, Hagens R. Conventional sunscreen application does not lead to sufficient body coverage. Int J Cosmet Sci. 2017;39(5):550-555. doi:10.1111/ics.12413

2Heerfordt IM, Torsnes LR, Philipsen PA, Wulf HC. Sunscreen use optimized by two consecutive applications. PLoS One. 2018;13(3):e0193916. Published 2018 Mar 28. doi:10.1371/journal.pone.0193916

3. Pratt H, Hassanin K, Troughton LD, et al. UV imaging reveals facial areas that are prone to skin cancer are disproportionately missed during sunscreen application. PLoS One. 2017;12(10):e0185297. Published 2017 Oct 2. doi:10.1371/journal.pone.0185297

4. Dennis LK, Vanbeek MJ, Beane Freeman LE, Smith BJ, Dawson DV, Coughlin JA. Sunburns and risk of cutaneous melanoma: does age matter? A comprehensive meta-analysis. Ann Epidemiol. 2008;18(8):614-627. doi:10.1016/j.annepidem.2008.04.006

5. Boothby-Shoemaker WT, Mohammad TF, Ozog DM, Lim HW. Photoprotection by Clothing: A Review [published online ahead of print, 2022 Jan 24]. Photodermatol Photoimmunol Photomed. 2022;10.1111/phpp.12776. doi:10.1111/phpp.12776

6. Hatch KL. American standards for UV-protective textiles. Recent Results Cancer Res. 2002;160:42-47. doi:10.1007/978-3-642-59410-6_6

7. Hoffmann K, Laperre J, Avermaete A, Altmeyer P, Gambichler T. Defined UV protection by apparel textiles. Arch Dermatol. 2001;137(8):1089-1094.

8. Gambichler T, Laperre J, Hoffmann K. The European standard for sun-protective clothing: EN 13758. J Eur Acad Dermatol Venereol. 2006;20(2):125-130. doi:10.1111/j.1468-3083.2006.01401.x

9. Gambichler T, Hatch KL, Avermaete A, Altmeyer P, Hoffmann K. Influence of wetness on the ultraviolet protection factor (UPF) of textiles: in vitro and in vivo measurements. Photodermatol Photoimmunol Photomed. 2002;18(1):29-35. doi:10.1034/j.1600-0781.2002.180105.x 10. Edlich RF, Cox MJ, Becker DG, et al. Revolutionary advances in sun-protective clothing–an essential step in eliminating skin cancer in our world. J Long Term Eff Med Implants. 2004;14(2):95-106. doi:10.1615/jlongtermeffmedimplants.v14.i2.30

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