Sunscreen 101

Sunscreen isn’t just for beach days—it’s a daily essential for maintaining healthy skin and preventing long-term damage. From premature aging to skin cancer, unprotected sun exposure poses serious risks.

Yet, not all sunscreens are created equal. With countless products on the market and a growing awareness of ingredient safety, knowing how to choose the right sunscreen is more important than ever.

Why Sunscreen Is a Non-Negotiable Part of Your Skincare Routine 

The sun emits ultraviolet (UV) rays—specifically UVA and UVB—that penetrate your skin and cause damage over time.

• UVA rays are responsible for premature aging, wrinkles, and sunspots. They penetrate deep into the skin and are present year-round, even on cloudy days.
• UVB rays are what cause sunburn and play a key role in the development of skin cancers, including melanoma.

Using sunscreen every day, even when it’s cloudy or you're indoors near windows, can significantly reduce your risk of skin cancer, prevent premature aging, and maintain an even skin tone.

What Makes a Sunscreen Effective? 

Broad-Spectrum Protection

Always choose a sunscreen labeled broad-spectrum. This ensures it protects against both UVA and UVB rays. Some sunscreens only protect against UVB, which helps with sunburn but not long-term damage like wrinkles or skin cancer.

SPF Rating

SPF (Sun Protection Factor) indicates how well a sunscreen protects against UVB rays.

• SPF 15 blocks about 93% of UVB rays
• SPF 30 blocks about 97%
• SPF 50 blocks about 98%
• SPF 100 blocks about 99%

While SPF 30 is usually sufficient for most people, those with fair skin, a history of skin cancer, or conditions like melasma may benefit from SPF 50 or higher.

Water Resistance 

If you’re swimming or sweating, opt for a sunscreen labeled as water-resistant for 40 or 80 minutes. This doesn’t mean it's waterproof (no sunscreen is), but it will stay effective for a limited time in water.

Proper Application

Even the best sunscreen won’t work if applied incorrectly. Use about a teaspoon for the face and a shot glass full for the body. Reapply every two hours—or immediately after swimming or sweating.

Physical (Mineral) vs. Chemical Sunscreens

Sunscreens fall into two main categories: mineral and chemical.

Mineral Sunscreens 

Also known as physical sunscreens, they use active ingredients like zinc oxide or titanium dioxide to sit on top of the skin and physically block or reflect UV rays.

Pros:

• Start working immediately after application
• Less likely to irritate sensitive skin
• Reef-safe and environmentally friendly
• Better option for children and people with rosacea or eczema

Cons:

• Can leave a white cast, especially on deeper skin tones
• May feel thicker or heavier on the skin

Chemical Sunscreens 

These absorb UV rays and transform them into heat, which is then released from the skin.

Common active ingredients include:

• Avobenzone
• Oxybenzone
• Octinoxate
• Octocrylene
• Homosalate

Pros:

• Easier to apply with a more invisible finish
• Often combined with moisturizers or cosmetics

Cons:

• Require about 20 minutes to become effective
• Can irritate sensitive or acne-prone skin
• Some ingredients may be harmful to coral reefs or have questionable safety data

Ingredients to Avoid in Sunscreens 

Not all ingredients found in commercial sunscreens are ideal for your skin or the environment. Here are some that are best avoided:

Oxybenzone

One of the most controversial sunscreen ingredients, oxybenzone has been shown to cause allergic reactions, disrupt hormones, and damage coral reefs. It is banned in Hawaii and some parts of the U.S. due to its ecological impact.

Octinoxate

Like oxybenzone, octinoxate is linked to hormone disruption and environmental damage. It can cause skin allergies and has been detected in breast milk, raising concerns about long-term exposure.

Homosalate

This UVB filter may accumulate in the body faster than it can be broken down, possibly disrupting hormone function. The FDA has flagged it for further safety testing.

Fragrance

Fragrance in sunscreens can irritate sensitive skin and lead to allergic reactions. If you have sensitive or reactive skin, opt for fragrance-free or hypoallergenic formulas.

Parabens

Used as preservatives, parabens have raised concerns about endocrine disruption and have been found in breast tissue. Look for products labeled paraben-free if you want to play it safe.

Top Recommended Sunscreen Ingredients 

If you’re looking for safer and effective ingredients, here are the top picks:

• Zinc Oxide: Offers broad-spectrum protection, anti-inflammatory properties, and is ideal for sensitive skin.
• Titanium Dioxide: Offers good UVB and partial UVA protection; often paired with zinc oxide for full-spectrum coverage.
• Avobenzone: The most effective UVA blocker among chemical filters, but it should be stabilized with other ingredients.
• Tinosorb S and M: Broad-spectrum filters not yet approved in the U.S. but used widely in Europe and Asia due to their effectiveness and photostability.

Best Sunscreen Types by Skin Type 

For Oily or Acne-Prone Skin:

• Look for non-comedogenic, oil-free formulas.
• Gel-based or water-based sunscreens work well.
• Mineral sunscreens with zinc oxide can help soothe inflammation.

For Dry Skin:

• Choose sunscreens with added moisturizers like glycerin, hyaluronic acid, or ceramides.
• Avoid alcohol-based formulations, which can be drying.

For Sensitive Skin:

• Mineral sunscreens are the safest bet.
• Avoid fragrance, parabens, and alcohol.

For Darker Skin Tones:

• Seek out tinted mineral sunscreens that blend without leaving a white cast.
• Lightweight chemical sunscreens may also be more cosmetically elegant, though ingredient safety should be considered.

Environmental Considerations 

Sunscreens can wash off into oceans and lakes, affecting marine life. Hawaii and other coastal regions have passed laws banning the sale of sunscreens with harmful ingredients like oxybenzone and octinoxate.

To be environmentally conscious:

• Choose reef-safe formulations.
• Use mineral sunscreens labeled "reef-safe" or "ocean-friendly."
• Avoid aerosol sprays, which often miss the skin and enter the air or ground.

Daily Use is Key

The best sunscreen is the one you’ll actually use—consistently and correctly. Whether you prefer a mineral-based cream or a lightweight chemical formula, prioritize broad-spectrum protection and a high enough SPF for your lifestyle.

Daily use of a safe, effective sunscreen is one of the most powerful ways to protect your skin—not just from sunburn, but from premature aging and skin cancer. Make sunscreen your skin’s best friend, not just a beach day afterthought.

Pro Tip: Apply sunscreen as the final step in your morning skincare routine, and don’t forget often-missed spots like your ears, neck, and the backs of your hands. Your future self (and your dermatologist) will thank you.