Your Sun Care Questions Answered: Reader FAQ
TL;DR
- Sunscreen expires and should be replaced after the expiration date or within three years of purchase
- Babies under 6 months should avoid sunscreen—use shade and clothing instead
- Many common concerns have straightforward solutions once you understand the science
Over the years, we've received countless questions about sun care. Some come up again and again because the answers aren't always intuitive or widely known.
This FAQ compiles the questions readers ask most frequently, with clear, science-based answers. Whether you're wondering about last year's sunscreen or how to layer SPF with makeup, you'll find your answer here.
Sunscreen Shelf Life and Storage
Q: Can I use last year's sunscreen?
A: Check the expiration date first. If it hasn't expired, it should still be effective. If there's no expiration date, sunscreens are required to maintain their labeled SPF for at least three years from manufacture—so if you know when you bought it and it's been less than three years, it should be fine.
However, if the product has changed in color, consistency, or smell, discard it regardless of the date. Heat exposure (like leaving sunscreen in a hot car) can degrade ingredients faster than expected.
Q: Does sunscreen actually expire?
A: Yes, absolutely. The active ingredients that filter UV rays break down over time. An expired sunscreen may provide significantly less protection than its label indicates—or no protection at all. The expiration date isn't just a suggestion.
Q: How should I store sunscreen to make it last?
A: Keep sunscreen in a cool, dark place at room temperature. Avoid leaving it in hot cars, direct sunlight, or humid bathrooms. Heat and light accelerate the breakdown of active ingredients. If you're at the beach, keep your sunscreen in a cooler or under a towel in the shade.
Babies and Children
Q: Can I use sunscreen on my baby?
A: For babies under 6 months, the FDA and American Academy of Pediatrics recommend avoiding sunscreen. Instead, keep babies out of direct sun entirely using shade, stroller canopies, and protective clothing including wide-brimmed hats.
For babies 6 months and older, mineral sunscreens (zinc oxide and titanium dioxide) are generally recommended as they're less likely to irritate sensitive baby skin. Apply to small areas of exposed skin not covered by clothing.
Q: What SPF should I use on my kids?
A: SPF 30 to 50 is appropriate for children. The key is generous application and frequent reapplication—every two hours and immediately after swimming or sweating. Kids' sunscreens are typically formulated to be water-resistant and gentle, but any broad-spectrum mineral sunscreen is suitable.
Sunscreen and Makeup
Q: Can I apply makeup over sunscreen?
A: Yes, but give your sunscreen a few minutes to absorb before applying makeup. Look for sunscreens labeled as suitable for use under makeup—these typically have lighter textures and matte finishes. Primers and foundations with SPF can add extra protection but shouldn't replace dedicated sunscreen.
Q: Does my SPF 15 foundation count as sun protection?
A: It provides some protection, but probably not enough. People typically don't apply enough foundation to achieve the labeled SPF (you'd need about 1/4 teaspoon for your face). Consider SPF makeup as a supplement to, not a replacement for, regular sunscreen.
Q: How do I reapply sunscreen over makeup?
A: Options include: powder sunscreens that can be dusted over makeup, SPF setting sprays (spray into hands and pat on), cushion compact sunscreens, or sunscreen sticks patted gently on top. These are touch-up solutions—your initial application in the morning should be a proper sunscreen layer.
Formulation and Efficacy
Q: How can I tell if my sunscreen is photostable?
A: Unfortunately, there's no required label indication for photostability in the US. Some tips:
- Sunscreens with avobenzone should also contain stabilizers (like octocrylene or Tinosorb S)
- Mineral sunscreens (zinc oxide, titanium dioxide) are inherently photostable
- Reputable brands generally formulate for stability
- If your sunscreen separates or changes color after sun exposure, it may be unstable
When in doubt, reapply regularly—this compensates for any stability issues.
Q: Is higher SPF actually better?
A: Higher SPF does block slightly more UV rays (SPF 30 blocks 97%, SPF 50 blocks 98%), but the difference becomes minimal at higher numbers. The main advantage of high SPF is margin of error—since most people under-apply sunscreen, starting with a higher SPF means you're more likely to end up with adequate protection. SPF 30 to 50 is generally the sweet spot.
Q: Do I need sunscreen on cloudy days?
A: Yes. Up to 80% of UV rays penetrate clouds. You can absolutely get sunburned on an overcast day. UV exposure is based on the UV index, which remains significant even when the sky isn't clear.
Application Concerns
Q: I'm supposed to apply sunscreen 15-20 minutes before sun exposure. Why?
A: This primarily applies to chemical sunscreens, which need time to absorb into the skin to work effectively. Mineral sunscreens work immediately upon application. That said, applying any sunscreen before you head outside ensures it's in place and dry by the time you encounter UV rays.
Q: How much sunscreen is "enough"?
A: For face and neck: about 1/4 to 1/2 teaspoon (some people use the "two finger" method—a line of product along two fingers). For the entire body in a swimsuit: about one ounce (a shot glass). Most people apply 25-50% of this amount, which dramatically reduces actual protection.
Q: Can I mix sunscreen with my moisturizer?
A: It's not recommended. Diluting sunscreen with other products reduces the concentration of UV filters and may affect the formula's ability to form an even, protective film. Apply moisturizer first, let it absorb, then apply sunscreen as its own layer.
Special Situations
Q: Does sunscreen prevent tanning?
A: Sunscreen significantly reduces tanning but doesn't prevent it entirely—no sunscreen blocks 100% of UV rays. Even with diligent sunscreen use, some melanin production occurs. If your goal is to prevent tanning entirely, you'll need to combine sunscreen with protective clothing and shade.
Q: Can I get vitamin D while wearing sunscreen?
A: Studies suggest that real-world sunscreen use doesn't significantly impair vitamin D production, partly because most people don't apply enough sunscreen to block all UV rays, and partly because incidental exposure (hands, face during brief outdoor moments) typically provides sufficient vitamin D. If you're concerned about vitamin D, talk to your doctor about supplementation rather than reducing sun protection.
Q: Do I need sunscreen indoors?
A: If you're near windows, yes—UVA rays penetrate glass. If you spend significant time near windows during daylight hours, wearing sunscreen helps protect against cumulative UVA exposure, which contributes to aging and can worsen hyperpigmentation.
Product Selection
Q: What's the difference between "sport" and regular sunscreen?
A: Sport sunscreens are typically more water-resistant and formulated to stay put during physical activity and sweating. If you're swimming or exercising, a sport formula is worthwhile. For regular daily use, standard formulas work fine.
Q: Mineral vs. chemical—which is better?
A: Neither is inherently "better"—they work differently and suit different needs. Mineral sunscreens are often preferred for sensitive skin and during pregnancy, while chemical sunscreens typically absorb more elegantly without white cast. The best sunscreen is one you'll use consistently.
Q: Why is my sunscreen pilling?
A: Pilling happens when products don't layer well together. Common causes include applying too much product, not letting layers absorb between applications, or ingredient incompatibilities between your skincare and sunscreen. Try applying thinner layers, waiting longer between steps, or changing products.
Key Takeaways
- Sunscreen does expire—check dates and discard products that have changed in appearance
- Babies under 6 months should be protected with shade and clothing, not sunscreen
- Sunscreen under makeup works, but give it time to absorb first
- Cloud cover doesn't eliminate UV exposure—protect yourself on overcast days
- The best sunscreen is one you'll actually use consistently and generously
FAQ
Q: Can I use face sunscreen on my body and vice versa?
A: Yes, though it may not be ideal. Face sunscreens are formulated for cosmetic elegance and may be too expensive to use liberally on your body. Body sunscreens may be too heavy or greasy for facial use and could cause breakouts on acne-prone skin. But in a pinch, any sunscreen is better than none.
Q: My sunscreen stings my eyes. What can I do?
A: Some chemical filters, particularly avobenzone, are known to migrate and sting eyes. Solutions include: using a mineral sunscreen around your eyes (zinc oxide is less likely to sting), applying sunscreen further from your eye area, using a sunscreen stick for the eye zone, or switching to a "sport" formula designed not to run.
Q: Is spray sunscreen safe to use?
A: Spray sunscreens are safe for body use when applied correctly—spray generously until skin glistens, then rub in. Avoid inhaling the spray and never spray directly on your face (spray into hands first). The main concern with sprays is that people tend to under-apply, so be generous.
