When it comes to sun protection, most of us just want to make sure we’re doing the
right thing. Patients often ask me, “Which sunscreen is best? How can I prevent another skin cancer? Does UPF clothing really work?” Let’s walk through the benefits and drawbacks of UPF clothing vs. SPF. By the end, you will have a confident answer on how to best protect your skin. If you want a quick summary on UPF vs. SPF, you can scroll to the bottom of this article.
Sunscreen is great but not perfect
As a dermatologist, I am a big advocate for sunscreen. It’s widely available, cheap, and
YES, it’s safe. However, there are many limitations to the real-world protection that sunscreen provides and it should be considered as only one part of your sun-protection plan.
One of the biggest challenges with sunscreen is the amount required to reach the SPF
on the label. Laboratory testing assumes an application of 2 mg per cm2 of skin, which equals a shot glass full, for the entire body. Most people use far less. In one randomized study, SPF 30 and SPF 50 provided actual protection closer to SPF 9 and SPF 14 with typical use. Because of this, I routinely recommend choosing SPF 50 or 70. If you wear UPF 50+ clothing, you can skip sunscreen on covered areas, significantly reducing the amount you need to apply!
Timing is another common mistake. Many people apply sunscreen only after arriving at
the beach or pool. Both chemical and mineral sunscreens need about 20 minutes to dry on the skin and form a continuous protective barrier. If you apply at the water’s edge, you may be unprotected during that window, especially when the UV index is high.
Perhaps the most negative aspect of sunscreen is that it needs to be re-applied. Over
time, the continuous sunscreen barrier that you meticulously applied in the correct amount will start to rub off, ball up, and degrade, giving you less SPF protection. This is why sunscreen needs to be reapplied every 2 hours. If you are swimming or sweating, you’ll want to reach for a sunscreen labeled “water-resistant” and re-apply every 40 or 80 minutes, depending on what the label says. So what if you’re in the pool or ocean and your 80 minutes is up? You should exit the body of water, dry off, reapply your sunscreen, and wait 20 minutes for it to fully dry before jumping back in. If this sounds like a lot of work, it is. UPF swimwear can make this a lot easier.
Sunscreens in the United States also have limitations in UVA protection, especially
against the longer wavelengths knowns as UVA1 (340-400 nm). To help understand this concept better, I’m going to give a quick review of the electromagnetic spectrum (if you’re a geek like me you’ll appreciate this next part).
Why do we care about blocking the sun’s rays anyway?
When it comes to skin, we are concerned about UVB (290-320 nm), UVA2 (320-340 nm), UVA1 (340-400 nm), and visible light. More than 95% of the sun’s rays that reach the earth’s surface are UVA and 80% of these rays are UVA1. Only 5% are UVB. Visible light reaches us in quantities roughly 12-14 times greater than UVA or UVB.
Visible light can worsen pigmentation and dark spots, especially in darker skin types.
UVB, and to a lesser degree UVA, contribute to signs of skin aging such as wrinkles, thin skin, and brown spots. UVB and UVA can lead to the formation of squamous cell carcinoma and melanoma. UVB is the primary cause of sunburns and basal cell carcinoma. We have numerous effective UVB blocking sunscreen ingredients in the U.S. but very few sunscreen ingredients that are approved by the FDA that offer meaningful protection against UVA1 (this is hopefully changing soon). Of those, zinc oxide, ecamsule, and avobenzone are the best. Zinc oxide coverage drops off around 370 nm, leaving little protection from 370-400 nm. Ecamsule and avobenzone cover more of the UVA1 spectrum. Ecamsule (Mexoryl SX) is a proprietory filter in L’Oreal products. Avobenzone is very unstable and degrades quickly unless formulated carefully
with photostabilizers like octycrylene. Titanium dioxide, and sulisobenzone are also available in the U.S. but offer less protection against UVA1 than the aforementioned filters.
Long wavelength UVA1 has a compounding effect with visible light, causing more
intense and persistent pigmentation compared with visible light or UVA1 alone. For protection against visible light, look for sunscreens that contain zinc oxide, titanium dioxide, or iron oxide.
All this discussion of sunscreen ingredients may be leaving you confused on which
sunscreen is best. Here is what I tell my patients- try not to sweat the details too much. The best sunscreen is the sunscreen that you enjoy wearing and are willing to reapply. Consistency matters more than perfection. Just make sure the SPF is at least 30 (higher is better) and the label states that it is broad spectrum (covers against both UVA and UVB rays).
UPF clothing helps bridge the gap
This brings us to UPF swimwear and clothing. One of the best parts about UPF
swimwear is that it is extremely effective at blocking UV rays. If your piece is UPF 50 +, it blocks over 98% of UV rays. However, because of the way UPF rating is calculated, it primarily reflects protection from UVB rays. In the United States, brands do not have to disclose if their garments have been tested to block UVA. However, all Helioshield fabrics have been lab tested by spectroscopy and block both >98% of UVA and UVB rays. With Helioshield you don’t have to worry about the gap in sunscreen coverage for UVA1 rays as described above.
My favorite benefit of UPF swimwear is convenience. I don’t have to struggle applying
sunscreen to hard-to-reach areas like my mid-back. A typical pool day for us looks like this: I get my 4-year-old ready, apply his sunscreen, and he excitedly runs off with my husband. Instead of wrestling with sunscreen application on my own back, I simply put on a long-sleeve rash guard and apply sunscreen only to my exposed areas.
Of course, UPF swimwear cannot cover your entire body, which is its biggest limitation.
This is why using both sunscreen and UPF clothing together is ideal. When thinking about sun protection, I often use the “Swiss cheese” analogy. One slice has holes, which represent the weaknesses of any single method. Stacking multiple slices reduces the chance that something will slip through. The best approach is to combine a UPF hat, UPF swimwear, sunglasses, sunscreen of at least SPF 30 (but again, higher SPF is better), seek shade when available, and avoid peak UV hours from 10 a.m. to 2 p.m. when possible.
Sources:
Abdel Azim S, El-Khateeb EA, Abdel-Halim MR, et al. Sunscreens part 1: Mechanisms and
efficacy. J Am Acad Dermatol. 2025;92(4):677-686. doi:10.1016/j.jaad.2024.01.012
Bolognia JL, Schaffer JV, Cerroni L, eds. Dermatology. 4th ed. Elsevier; 2018.
Boothby-Shoemaker WT, Wyatt EL, et al. Photoprotection by clothing: A review. Photodermatol Photoimmunol Photomed. 2022;38(5):478-488. doi:10.1111/phpp.12736
Kim MA, Kim HJ, Lee HJ, et al. Layering sunscreen with facial makeup enhances its sun
protection factor under real-use conditions. Skin Res Technol. 2021;27(5):692-699.
doi:10.1111/srt.13023
National Academies of Sciences, Engineering, and Medicine. Review of Fate, Exposure, and Effects of Sunscreens in Aquatic Environments and Implications for Sunscreen Usage and Human Health. Chapter 2: Sunscreen Ingredients and Their Safety. In: Environmental Impact of Currently Marketed Sunscreens and Potential Human Impacts of Changes in Sunscreen Usage. Washington, DC: National Academies Press; 2022. Published August 9, 2022.
Pham H, Hahn MS, et al. Use of mineral foundation products claiming SPF alone does not
provide adequate sun protection to the consumer. J Am Acad Dermatol. 2008;58(2 suppl
2):AB25.
Ashley Steffens, M.D., F.A.A.D., December 2025
