Protecting your skin is important year-round. And even more so as we spend more time outdoors enjoying the summer months. Too much sun exposure to the sun’s harmful UV rays can increase your risk for skin cancer, the most common cancer in the United States.
Dr. Jimena Cervantes, a physician at the University Health Skin Clinic, shares answers to common questions about sun protection, helping you care for your skin so you can safely enjoy the sun.
What Is Sunburn?
“Sunburn is your skin’s response to excessive UV exposure,” explains Dr. Cervantes. “Even one sunburn can increase your risk of skin cancer and accelerate signs of skin aging over time.”
Research shows that repeated sunburns significantly raise your risk of melanoma, the most serious form of skin cancer. The good news is that sunburn is preventable. Simple daily habits — like applying broad-spectrum sunscreen, seeking shade and wearing protective clothing, such as hats and sunglasses — can go a long way in protecting your skin.
How Often Should I Reapply Sunscreen When Spending Time Outdoors?
Apply sunscreen about 15 minutes before going outside to allow it to absorb fully. For the body, aim for about 1 ounce (a shotglass–sized amount) to cover all exposed skin. For the face, the “three-finger rule” is a helpful guide: apply a line of sunscreen along your index, middle and ring fingers, roughly 1 teaspoon.
“Most people don’t apply enough sunscreen, so it’s better to use more than you think you need,” says Dr. Cervantes.
Reapply every two hours while outdoors and more often if you’re swimming or sweating. After being in the water, gently dry your skin before reapplying. When possible, choose a water-resistant sunscreen for added protection.
Did you know…UV exposure isn’t just from being outside?
Driving and sitting near windows also contribute to daily sun damage. That’s why daily sunscreen (and reapplication) matters.
What Does SPF Mean?
SPF stands for “sun protection factor” and refers to how well a sunscreen protects your skin from UVB rays, the main cause of sunburn.
“For daily use, choose a broad-spectrum sunscreen with an SPF of at least 30,” says Dr. Cervantes. “Broad-spectrum means it protects against both UVA rays, which contribute to skin aging, and UVB rays, which cause sunburn.”
No sunscreen blocks 100% of UV rays, but SPF 30 filters about 97% of UVB rays. Higher SPF offers slightly more protection, but it does not mean you can stay in the sun longer. No matter the SPF, reapplication every two hours is key.
What Should I Look for When Buying Sunscreen?
When choosing a sunscreen, keep these important factors in mind:
- SPF 30 or higher for daily use
- Broad-spectrum protection (UVA + UVB coverage)
- Water-resistant formulas for swimming or sweating
Applying Sunscreen Tips
- Lotions and creams are best for initial application to ensure even, adequate coverage.
- Sprays and sticks are great for reapplication, especially on the go.
- When using sprays, apply generously and rub it in, especially for areas like the scalp or other hard-to-reach spots.
- Don’t forget commonly missed areas like the eyelids, ears and lips (use an SPF lip balm).
What Is the Difference Between Chemical and Mineral Sunscreen?
“The best sunscreen is the one you will wear consistently,” says Dr. Cervantes.
- Mineral (physical) sunscreens contain zinc oxide and/or titanium dioxide. They sit on the skin's surface and reflect UV rays. These are a great option for sensitive skin and for children (6 months and up).
- Chemical sunscreens absorb UV rays and convert them into heat. They tend to be lightweight and easier to blend, but may irritate some individuals.
Is Tinted Sunscreen a Good Idea?
Tinted sunscreens (often containing iron oxides) not only provide UV protection but also help protect against visible light, which can contribute to conditions like hyperpigmentation. They can also blend more naturally into a range of skin tones.
“I often recommend tinted sunscreen to my patients. It’s what I wear daily instead of foundation or makeup,” says Dr. Cervantes. “There are also great options now like SPF blush and colored lip balms, making it easier to incorporate sun protection into your routine.”
Does My Skin Color Determine if I Need to Apply Sunscreen?
“No. Everyone’s skin needs protection from UV rays,” says Dr. Cervantes.
Sunscreen is important for all skin tones. While people with lighter skin may burn more easily due to lower melanin levels, individuals with darker skin are still at risk for sun damage, premature aging and skin cancer, often diagnosed at later stages.
Daily sun protection also helps prevent uneven skin tone and hyperpigmentation. For many patients, tinted sunscreens can be especially helpful. These formulas contain iron oxides, which provide additional protection against visible light, which is a known trigger for conditions like melasma and dark spots. It also blends more naturally into a variety of skin tones.
No matter your skin type or tone, wearing sunscreen every day is one of the most important steps you can take to protect and maintain healthy skin.
Do I Need to Apply Sunscreen Even if My Foundation Has SPF?
“Yes. Makeup with SPF is not enough on its own,” says Dr. Cervantes.
Most people don’t apply enough foundation to get the full SPF protection listed on the label. For proper protection, it’s important to apply dedicated sunscreen as your base layer.
Should I Mix My Foundation with SPF?
No. Sunscreen and foundation work best when applied separately. Mixing them can dilute the sunscreen, making it less effective and reducing your protection.
Apply sunscreen first, let it absorb and then apply your makeup. For reapplication throughout the day, options like sunscreen sticks, powders or sprays can be helpful, especially when wearing makeup.
Does Sunscreen Expire?
Yes — sunscreen does expire. You can find the expiration date on the packaging and most sunscreens are effective for up to three years if stored properly.
Heat and sunlight can break down the active ingredients, so store your sunscreen in a cool, shaded place. If your sunscreen has expired or has changed in texture or smell, it’s time to replace it.
“Using expired sunscreen can leave your skin unprotected,” says Dr. Cervantes.
Is Wearing Sunscreen the One Way to Prevent Skin Cancer?
No. Sunscreen is just one part of protecting your skin.
For the best protection, combine sunscreen with other sun-safe habits:
- Seek shade, especially during peak sun hours (typically 10 a.m.-4 p.m.)
- Wear protective clothing, including long sleeves and wide-brimmed hats
- Choose clothing with a UPF (Ultraviolet Protection Factor) rating for added protection
- Use sunglasses to protect your eyes and the delicate skin around them
Taking a comprehensive approach helps reduce your risk of skin cancer, prevent premature aging and keep your skin healthier over time.
Think of sunscreen as one layer of protection, but not the only one.
Primary Care at University Health
Protecting your skin isn’t just about avoiding a sunburn today. It’s about reducing your risk of skin cancer and maintaining healthy skin for years to come. The sun doesn’t take a day off, so protecting your skin shouldn’t either.
If you have questions or aren’t sure which sunscreen is right for you, the primary care team at University Health is here to help you make confident, informed choices for your skin.
