Choosing a sunscreen comes down to four things: SPF level, broad spectrum protection, the right formula for your skin, and whether you’ll actually wear it consistently. Most people overthink the brand and underthink the label. Here’s what to look for and why it matters.
What SPF Number You Actually Need
SPF measures how well a sunscreen blocks UVB rays, the type that cause sunburn and play a major role in skin cancer. The numbers follow a curve of diminishing returns: SPF 15 blocks 93% of UVB rays, SPF 30 blocks 97%, and SPF 50 blocks 98%. That jump from 30 to 50 sounds small, but it means SPF 50 lets in half as much burning radiation as SPF 30. For everyday use, SPF 30 is the widely recommended baseline. SPF 50 or higher makes sense if you burn easily, spend long stretches outdoors, or have a history of skin cancer.
Going above SPF 50 offers almost no additional protection and can create a false sense of security that leads people to skip reapplication. The number on the bottle also assumes you’re applying the right amount, which most people don’t. In practice, using SPF 30 generously and reapplying it will protect you better than using SPF 100 sparingly.
Why “Broad Spectrum” Is Non-Negotiable
SPF only measures UVB protection. UVA rays penetrate deeper into the skin, accelerate aging, and contribute to skin cancer, but they won’t give you a sunburn, so you won’t feel the damage happening. A sunscreen labeled “broad spectrum” has passed an FDA test showing it protects against both UVA and UVB radiation. Specifically, it must demonstrate a critical wavelength of at least 370 nanometers, meaning its protection extends well into the UVA range rather than only covering the shorter UVB wavelengths.
If the label doesn’t say “broad spectrum,” the product may only reduce your sunburn risk while leaving your skin exposed to the deeper, aging effects of UVA. Always check for those two words before anything else on the bottle.
Mineral vs. Chemical Sunscreen
Sunscreens use one of two approaches to block UV light, and understanding the difference helps you pick the right one for your skin and lifestyle.
Mineral sunscreens (sometimes called physical sunscreens) use zinc oxide or titanium dioxide. These sit on top of the skin and work like a shield, reflecting and scattering UV rays before they reach you. They start working the moment you apply them and tend to be gentler, making them a good fit for sensitive or reactive skin. The tradeoff is texture: mineral formulas can leave a white cast, especially on deeper skin tones, though many newer formulations have reduced this significantly.
Chemical sunscreens use synthetic filters that absorb UV rays like a sponge, converting them into heat that dissipates from the skin. They tend to rub in more easily, feel lighter, and layer well under makeup. However, some chemical filters can irritate sensitive skin or trigger breakouts. They also need about 15 to 20 minutes after application to become fully effective.
Many modern sunscreens blend both mineral and chemical filters to balance protection, wearability, and cosmetic feel. Neither type is categorically better. The best one is whichever you’ll use every day without skipping.
Choosing for Oily, Acne-Prone, or Sensitive Skin
If your skin breaks out easily, look for sunscreens labeled “non-comedogenic,” which means they’re formulated to avoid clogging pores. Ingredients like zinc oxide, niacinamide, and silica help control shine and calm inflammation rather than aggravating it. Avoid heavy emollients, coconut oil, and thick occlusive ingredients, all of which can trap oil and trigger breakouts.
Fragrance is one of the most common irritants in sunscreen. If you have sensitive or acne-prone skin, choose fragrance-free and alcohol-free formulas. Added fragrance can worsen inflammation and trigger new blemishes even in products that are otherwise well-formulated. Gel or fluid textures generally work better for oily skin than creams, while cream-based mineral sunscreens suit dry or sensitive skin types well.
Water Resistance for Swimming and Sweat
No sunscreen is waterproof. The FDA banned that term from labels because it’s misleading. What you’ll see instead is “water resistant,” followed by either 40 minutes or 80 minutes. That number tells you how long the sunscreen maintains its SPF level during swimming or sweating before you need to reapply.
If you’re heading to the beach, a pool, or an outdoor workout, choose an 80-minute water-resistant formula. Reapply immediately after toweling off regardless of the time, since rubbing removes the protective layer. For everyday commuting or errands, water resistance is a nice bonus but not essential.
How Much to Apply (and How Often)
Most people apply about a quarter to half of the sunscreen they actually need, which dramatically reduces the protection they’re getting. For your entire body, the target is about one ounce, roughly the amount that would fill a shot glass. For your face and neck alone, use about half a teaspoon: a quarter teaspoon for the face, and another quarter teaspoon for the neck.
Reapply every two hours when you’re outdoors, or more often if you’re swimming or sweating. This matters even with high SPF, because sunscreen breaks down with UV exposure over time. Don’t forget commonly missed spots like the ears, the back of the neck, the tops of the feet, and along the hairline.
Reef-Safe Sunscreen and Environmental Impact
Several chemical sunscreen filters have been linked to coral bleaching and damage to marine ecosystems. Oxybenzone and octinoxate are the most studied offenders, and Hawaii banned both in 2018, with island nations like Palau, Bonaire, and Aruba following shortly after. Other ingredients flagged as harmful to ocean life include octocrylene, homosalate, and parabens.
If you’re swimming in the ocean, look for mineral sunscreens that use non-nano zinc oxide or titanium dioxide and skip the chemical filters entirely. Check that the label specifies “non-nano” or “micro-sized” particles. If a mineral sunscreen rubs in completely clear with no white cast, it likely uses nano-sized particles, which can still pose risks to aquatic organisms. The term “reef safe” isn’t regulated, so reading the ingredient list yourself is more reliable than trusting a marketing claim on the front of the bottle.
Sunscreen Sold Outside the U.S.
If you’ve ever tried a European or Asian sunscreen and noticed it felt better or offered stronger UVA protection, you’re not imagining it. Several advanced UV filters, including Tinosorb S, Tinosorb M, and Mexoryl SX/XL, are approved and widely used in Europe, Australia, and Asia but have not yet received FDA approval in the United States. These filters offer broader and more stable UVA protection than many of the chemical filters available in American products.
This doesn’t mean U.S. sunscreens are ineffective. A broad-spectrum SPF 30 or higher from an American brand still provides strong protection. But if you travel or order sunscreen internationally, you may find formulas with superior UVA coverage and lighter textures than what’s on your local drugstore shelf.
Storage and Shelf Life
Sunscreen lasts about three years from the date of manufacture unless the label states otherwise. After that, the active ingredients degrade and the product may not deliver the SPF on the label. Some bottles include an expiration date; if yours doesn’t, write the purchase date on it with a marker so you can track it.
Heat and sunlight speed up this breakdown considerably. Leaving a bottle in a hot car, on a sunny windowsill, or tossed in a beach bag for hours reduces its effectiveness well before the three-year mark. Store sunscreen in a cool, dry place at home, and keep it in the shade (a cooler or inside a bag) when you’re outside. If the texture has separated, the smell has changed, or the consistency looks off, replace it.