Are Your Summer Clothes Good Enough To Be Sun Protective Clothing?

does clothing block UV

Does clothing block UV? Are your summer outfits good enough to protect your skin from UV damage? Do you need to invest in UPF 50 fabric summer clothing?

Actually, most regular summer garments don't give your skin enough sun protection. That's because damaging UV rays can pass directly between the weave of the fabric's fibers as well as right through them! It's true!!

One-third of the clothing that you wear in summer does NOT block UV rays adequately to prevent sun damage.

You'll tan, burn, and get sun damage UNDER your cloths. I've seen it for over 30 years doing 200,000+ skin exams in my California dermatology practice - sun freckling, tanning and even skin cancers on the upper back and shoulders of people who are not directly exposing their skin to the sun.

Understanding how to use clothing for sun protection will save you on sunscreen, provide you with convenient sun protection, actually keep you cool and it can even be a fashion statement if you do it right.

Why does summer clothing fail to block enough UV rays?

  • One-third of summer clothes are feeble when it comes to sun protecting skin. This is especially true for lightweight, thin fabric made of cotton, linen and rayon.
  • The best sun protection comes from fabric you're not likely to wear in the summer like thick and tightly woven fabric, dark colors, polyester, nylon and wool.
  • Wet, stretched fabric provides poor sun protection (think wet white cotton tee shirt). Interestingly, a dark tee shirt will probably provide more protection than a light-colored one because the color alone also helps absorb UV rays.
  • Fuzzy, new, unbleached cotton sometimes provides good sun protection when it's dry, but UV rays can pass through cotton fibers.

Yes, I really do see sun exposure, sun damage and skin cancers on the backs of people who I know are not exposing their skin to the direct sun, especially after summer. My patients and I can only assume the problem is sun coming through their shirts.

Now, the good news:

It's easy to buy or make sun protective clothing for the best UV protection!

You can buy proven UPF 50 sun protective clothing from companies like REI, Coolibar etc. The styles are pretty generic, but the garments often contain hidden vents, zippers that open for ventilation and other clever tricks to keep you cool in sunny, hot places. (Think tropical vacation, hiking in the sun, gardening, cycling, etc.) Some of the UPF 50 fabric's protection will wear out over time. Coolibar uses fabric that will provide UPF 50 protection for the lifetime of the garment. They are the UPF 50 brand that I shop from and trust for my skin.

The big surprise -- You can make sun protective clothing out of what's already in your closet using a product called Sun Guard. This is really cost effective! 

How to make sun protective clothing at home.

For $4 you treat an entire load of laundry, saving serious money and giving you fashion control. Sun Guard contains Tinosorb which binds to the fabric fibers and then absorbs the UV rays. I've used it many times and it's never damaged or changed the look or feel of the fabric. I've done the washing machine treatment recommended on the box. I have also done it in the sink.

For fun, I added sun protection to a shirt that I packed for a super intense equatorial vacation escape. In the hotel room sink I gave this new cotton knit shirt complete sun protective power and took pictures to show how well it worked. 

You can see in the photos below. I used my Detecto Ring to demonstrate the effectiveness of the process. The Detecto Beads are white until UV rays hit them. The beads become colored upon exposure to UV rays.

  • See the beads change color to indicate that UV rays went through the fabric before Sun Guard treatment.
  • After the treatment, no color change with the Detecto Ring beads. This was at 12 noon on the equator!
test for does clothing block UV
Detecto Ring under the untreated shirt at 12 noon, see the slight color
does clothing block UV - simple test
Detecto Ring under a purchased UPF 50 sun protection shirt at 12 noon
The same shirt after Sun Guard treatment. The Detecto Ring beads hardly turn color indicating that the shirt now has much better sun protection.
The same knit cotton shirt after Sun Guard treatment. The Detecto Ring beads hardly turn color indicating much that the shirt now has much better sun protection.
Intense color to Detecto Beads without the shirt's protection at 12 noon
Intense color to Detecto Beads without the shirt's protection at 12 noon

There are other things you can do with your summer clothing to enhance sun protective benefits and prevent fabric from losing its ability to block UV rays. Some of these are surprising aspects of fabric/UV interaction.

Dermatologist's 3 tips for how to use your laundry care to create better sun protection from your clothing.

  1. Use detergents with 'optical brighteners' for your summer clothes. These optical brighteners actually absorb UV rays, releasing the energy as 'fluorescence' -- hence the bright look and more sun protection.
  2. Let your clothing shrink a little. This will increase sun protection because the spaces between the fabric fibers are tighter.
  3. Don't use bleach; bleaching decreases sun protection so try to avoid it, especially for cotton and rayon fabric.
Wishing you wonderful and sun damage free adventures!
Cheeky cockatoo on the hotel balcony waiting to raid the in-room minibar if I leave the door open! Wishing you wonderful and sun damage-free-adventures!


Photoprotection: A Review of the Current and Future Technologies, Steven Q. Wang et. al., Dermatologic Therapy, Vol. 23, 31-47

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