If you think sunburn is the only sign of skin damage, think again. While UVB rays are responsible for those painful red burns, UVA rays are the quiet culprit behind premature aging, sun spots, and all major types of skin cancer, though their role is often underestimated compared to UVB.
And here’s what many people don’t realize: UVA rays are present all day, every day, whether it’s sunny, cloudy, or even if you’re indoors near a window. In fact, UVA rays account for the vast majority of UV exposure we get over our lifetimes. So even when you’re not getting sunburned, your skin is still exposed to the kind of UV radiation that causes lasting damage, affecting both its health and appearance.
Let’s take a closer look at what UVA rays are, how they differ from the other UV rays, and why that matters for protecting your skin every day.
What Are UV Rays?
To understand UVA rays and their impact on your skin, it helps to start with the basics. There are three types of ultraviolet (UV) rays: UVA, UVB, and UVC. UVC rays are absorbed by the Earth’s atmosphere and don’t reach the ground. That leaves UVA and UVB as the primary rays we need to protect against.
UVB rays account for just 5% of the UV radiation that reaches Earth’s surface. They primarily affect the outermost layer of skin and are best known for causing sunburn. UVA rays, which make up the remaining 95%, penetrate deeper and contribute to long-term effects like premature aging and increased cancer risk.
UVA vs. UVB: Understanding the Differences
Although both UVA and UVB rays come from the sun, they affect your skin in different ways. This side-by-side comparison breaks down the key differences to help you understand why protection from both matters.
| Feature | UVA Rays | UVB Rays |
|---|---|---|
| Wavelength | 315–400 nanometers | 280–315 nanometers |
| Penetration | Deep into the dermis (middle layer) | Primarily the epidermis (outer layer) |
| Skin Effects | Wrinkles, sagging, dark spots, uneven tone | Sunburn, inflammation, redness |
| DNA Damage | Indirect, via oxidative stress | Direct, affecting DNA and RNA |
| Cancer Risk | Linked to all major skin cancers | Strongly linked to melanoma, basal cell carcinoma (BCC), and squamous cell carcinoma (SCC) |
| Consistency | Present year-round, all day long | Peaks midday and during summer |
| Penetrates Glass/Clouds | Yes | No (mostly blocked) |
While UVB causes more immediate, visible damage, UVA is the constant contributor to aging and long-term harm. Both are harmful in different ways, which is why daily, broad-spectrum protection is essential.
What Are UVA Rays?
UVA (Ultraviolet A) rays have longer wavelengths, ranging from 315 to 400 nanometers, placing them at the far end of the UV spectrum. They reach deep into the dermis, where collagen and elastin provide skin with structure and elasticity. Over time, UVA rays quietly break down these fibers, leading to visible signs of aging.
Unlike UVB rays, which peak during midday and vary with seasons, UVA rays remain steady from sunrise to sunset, all year long. They can even pass through clouds and window glass, exposing you to damage indoors and on overcast days.
Though they don’t cause sunburn, UVA rays still pose a serious threat. Their deep penetration leads to oxidative stress, interferes with your skin’s repair processes, and contributes to all major forms of skin cancer.
Cumulative UVA damage plays a role in:
- Wrinkles
- Sagging skin
- Dark spots and uneven tone
- Long-term DNA damage that increases skin cancer risk
Because the effects aren’t always visible right away, UVA rays are often underestimated. But daily exposure adds up. That’s why consistent protection matters, even when the damage isn’t visible. Cumulative UV exposure is a slow process, but its effects can be long-lasting.
Are UVA Rays Present All Day?
Yes. UVA rays stay relatively constant from sunrise to sunset, regardless of season. Whether it's early morning or late afternoon, UVA exposure remains steady.
Clouds and standard windows do little to block these rays. That means you're still exposed while commuting to work, sitting by a window, or even stepping outside for briefly. Whether you're indoors near a window or outside on a cloudy day, UVA still reaches your skin.
Does the UV Index Include UVA?
Not really. The UV Index mainly reflects UVB strength, which is associated with sunburn. So when the index reads "low," it usually means lower UVB, not lower UVA. This can lead people to assume there’s little to no risk when that isn’t the case.
Still, checking the UV Index daily is a healthy habit. It gives you an overall idea of UV intensity and helps you take extra precautions when needed. Just remember that UVA is always present, even on low-index days, which is why year-round protection matters.
What Does UVA Do to Your Skin?
UVA rays are often described as the invisible threat. You don’t feel them, and they don’t leave a burn like UVB, but the damage adds up over time. In fact, up to 90% of visible skin aging is caused by UV exposure, most of it from UVA.
UVA Rays and Aging
Think of UVB as a sunburn on the surface. UVA goes deeper, like radiation that sneaks past the surface and quietly alters your skin’s support structure. This triggers oxidative stress, breaks down collagen, and accelerates signs of aging like wrinkles, fine lines, and sagging skin.
Collagen and elastin are key proteins that give your skin its firmness, elasticity, and strength. When they break down, skin becomes thinner, looser, and less resilient. UVA damage also interferes with your skin’s natural repair process, making it harder to recover from everyday environmental stressors and visible damage over time.
One of the most striking examples is the case of a truck driver who developed severe photoaging on the left side of his face, the side closest to the window. After 28 years of daily driving, UVA rays passing through the glass led to deep wrinkles and sagging on one side while the other remained relatively smooth. If you’re curious what long-term UVA damage can really look like, the photo tells the story more powerfully than words ever could.
The Role of UVA in Immunosuppression
UVA exposure doesn’t just damage DNA. It also weakens the skin’s immune defenses, making it harder for your body to recognize and eliminate abnormal or precancerous cells. Even small amounts of daily exposure can reduce your skin’s ability to defend itself.
What Types of Skin Cancer Are Linked to UVA?
While UVB rays are strongly linked to the development of melanoma, basal cell carcinoma (BCC), and squamous cell carcinoma (SCC) due to their direct DNA-damaging effects, UVA plays a major role in cancer development too. Long-term UVA exposure contributes to all major skin cancers by generating oxidative stress, causing indirect DNA damage, suppressing immune function, and interfering with the skin's ability to repair itself. This includes:
- Melanoma
- Basal cell carcinoma (BCC)
- Squamous cell carcinoma (SCC)
- Ocular melanoma (a rare but serious cancer of the eye)
The link between UVA-rich tanning beds and higher rates of melanoma, BCC, and SCC further highlights its role in skin cancer development.
Are UVA Rays Often Overlooked?
Yes, and that’s part of the problem. Because UVA doesn’t cause burning, many people:
- Only apply sunscreen during summer or when it’s sunny
- Skip protection indoors or on overcast days
- Choose products based solely on SPF, which only measures UVB protection
This leads to daily exposure with little to no defense, exactly the kind of slow, cumulative damage UVA is known for.
How to Protect Yourself from UVA Rays
You don’t need to be afraid of UVA rays or feel like you have to avoid the sun completely. You just need a smarter, more consistent approach to help you live well under the sun. This information isn’t here to scare you, it’s here to help you build practical, realistic sun protection habits that fit your real everyday life. Here’s what helps:
1. Recognize That UVA Poses a Risk to Everyone
No matter your skin tone, UVA rays can still cause harm. While darker skin naturally contains more melanin, which offers some protection, it doesn’t block UVA entirely. People of all skin types can experience signs of aging, pigmentation changes, and skin cancer due to cumulative UVA exposure. Daily sun protection supports healthier skin for everyone, regardless of age or skin tone.
2. Wear UPF Clothing
Unlike sunscreen, sun-protective clothing provides all-day, broad-spectrum coverage without reapplication. UPF 50+ fabrics block 98% of UVA and UVB rays, making them one of the easiest and most effective ways to stay protected.
Essuntials UPF 50+ clothing is soft, breathable, and built for everyday wear, so you don’t have to choose between comfort and protection. Our fabrics are independently tested by third-party labs to ensure they maintain UPF 50+ protection even after 40 washes. One shirt provides the same coverage as about 8 bottles of sunscreen, saving you time, mess, and roughly $57 in sunscreen costs over time.
3. Use Broad-Spectrum Sunscreen
Look for "broad-spectrum" on the label to ensure coverage against both UVA and UVB rays. Not all broad-spectrum products offer equal UVA protection, so it's helpful to know how labeling works in different regions.
In Europe, you’ll often see a UVA logo inside a circle, which indicates that the product meets a minimum standard for UVA protection relative to its SPF. In Asia, many products use the PA rating system, where PA+++ or PA++++ signals stronger UVA coverage. In the U.S., broad-spectrum sunscreen is defined more generally, and the labeling doesn’t always reflect how much UVA protection is present.
Quick sunscreen label guide:
- SPF – Measures UVB protection
- Broad-spectrum – Includes UVA protection
- PA+++ – Strong UVA protection (common in Asian products)
- UVA in a circle – European UVA protection standard
4. Apply Sunscreen the Right Way
To get full protection, proper application is just as important as choosing the best sunscreen for your lifestyle:
- Generously apply about a shot glass worth for your body and half to one teaspoon (or two to three finger lengths) for your face and neck
- Apply 15 minutes before sun exposure
- Reapply every two hours or after sweating or swimming
Even small areas of your skin can be vulnerable to damage, so be sure to apply sunscreen to spots that are often missed, including your lips, ears, neck and chest, the backs of your hands, and your scalp or part line.
5. Stay in the Shade
While UVB rays peak during midday, UVA rays stay steady from morning to evening and can reach you even in the shade. Still, minimizing direct sun exposure is a helpful part of any UVA protection strategy. When you're outdoors, look for UVE-rated shade structures such as covered patios, UV-filtering umbrellas, or awnings. These are specifically designed to block both UVA and UVB rays more effectively than standard shade.
6. Don’t Forget Eye Protection
UVA rays can damage the eyes and the skin around them. Choose sunglasses labeled UV400 or 100% UVA/UVB protection, and wear a wide-brimmed UPF hat for added shade.
UVA Protection FAQs
Still have questions about UVA rays and how to protect yourself? You're not alone. Here are some common questions with answers to help you stay safe and confident in your daily sun protection routine.
Does UVA come through windows or clouds?
A: Yes. Standard window glass blocks UVB rays but lets most UVA rays through. That means you’re still exposed to UVA when you’re sitting near a window or driving in your car. The same goes for cloudy days, up to 90% of UVA rays can penetrate cloud cover. So whether it’s sunny or overcast, indoors or outside, UVA exposure adds up. That’s why daily protection matters.
Do I need protection for short periods outside?
A: Yes, it's a good idea. UVA exposure adds up over time, even in small moments. You don’t need to overthink it. Just aim for simple, consistent habits like wearing UPF clothing or applying sunscreen before you head out. Little steps can make a big difference.
Do regular clothes protect against UVA rays?
A: Most regular clothing provides limited UVA protection unless it’s specifically designed for it. Lightweight or light-colored fabrics often let UVA rays through. If you’re wearing standard clothing, it’s a good idea to apply sunscreen underneath. With UPF-rated clothing, you don’t need sunscreen underneath because UPF 50 fabrics are made to block 98% of UVA and UVB rays, offering reliable protection on their own.
Is makeup with SPF enough?
A: Only if it’s broad-spectrum and applied in the right amount. Most people don’t apply enough makeup to get full protection and rarely reapply it throughout the day. Consider adding a UPF hat for extra coverage.
Can UVA rays cause sun allergies?
A: Yes. In many cases, UVA rays are the primary trigger for sun-related skin allergies. Conditions like polymorphous light eruption (PMLE) and photoallergic reactions are typically caused by UVA exposure. If you experience itching, rashes, or hives after being in the sun, UVA could be the reason, especially if symptoms appear even on cloudy days.
Does a tan protect me from UVA?
A: No. A tan is a sign of skin damage. It doesn’t prevent deeper UVA effects.
Can UVA rays help me make vitamin D?
A: No. Vitamin D production is triggered by UVB rays. UVA doesn’t contribute to this process.
Is UVA protection important for kids too?
A: Yes. Children’s skin is more sensitive and vulnerable to long-term damage. Using UPF clothing, broad-spectrum sunscreen, and UPF-rated hats helps build healthy habits and protect their skin early on.
Should adults still use UVA protection?
A: Absolutely. It’s never too late to benefit from UVA protection. Even if sun damage has already occurred, daily protection can help prevent further aging and reduce the risk of skin cancer.
TL;DR: What to Know About UVA
- UVA rays are present every day, from morning to evening
- They cause visible aging, uneven pigmentation, and contribute to skin cancer
- Most of your lifetime UV exposure comes from UVA
- The UV Index doesn’t measure UVA, so don’t rely on it alone
- Use broad-spectrum sunscreen, UPF clothing, and daily habits to stay protected
The Essential Takeaway: Prioritize UVA Protection Every Day
Just because you can’t see or feel UVA damage doesn’t mean it isn’t happening. The good news? It’s never too late to start protecting your skin.
Already spent years in the sun without protection? You can still make a difference. Daily UVA protection helps prevent future damage, and consistent care gives your skin a chance to repair.
Sun protection isn’t about perfection. Every effort you make to be more mindful of your sun exposure is a worthwhile investment in your skin’s future.
Make sun protection part of your routine, just like brushing your teeth. Your future self and your future skin will thank you.
Live well under the sun!
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