10 things you didn’t know about sun cream

Ah, sun cream—the unsung hero of beach bags and summer picnics! We slather it on to fend off sunburns and keep our skin youthful, but how much do we know about this creamy, protective potion? While we might think of sun cream as just another summertime necessity, there's a whole lot more to this UV-fighting formula than meets the eye. So, grab your favourite pair of sunglasses, find a shady spot, and let’s dive into ten surprising facts about sun cream that will have you rethinking your sun protection strategy.

Not All Sunscreens Protect Against All UV Rays

Sun creams are designed to protect your skin from the sun’s harmful ultraviolet (UV) rays, but not all of them cover the full spectrum. UV rays are divided into UVA and UVB. UVA rays penetrate deeply into the skin and contribute to ageing and long-term skin damage, while UVB rays cause sunburn and are primarily responsible for skin cancer. Look for "broad-spectrum" on the label to ensure protection against both.

SPF Numbers Aren't Linear

The Sun Protection Factor (SPF) number indicates how long you can stay in the sun without getting burned. However, SPF 30 doesn't provide twice the protection of SPF 15. SPF 15 blocks about 93% of UVB rays, while SPF 30 blocks 97%, and SPF 50 blocks about 98%. Higher SPFs offer only slightly more protection.

You Need More Than You Think

Most people apply only 25-50% of the recommended amount of sunscreen. You should apply about a shot glass worth (1 ounce) to cover your entire body and a nickel-sized dollop for your face. Reapply every two hours, or immediately after swimming or sweating.

Expiration Dates Matter

Yes, sunscreen does expire. Over time, its active ingredients break down and become less effective. Always check the expiration date on the bottle, and if you can't find one, assume a shelf life of about three years. Discard any sunscreen that has changed colour or consistency.

Chemical vs. Mineral Sunscreens

There are two main types of sun creams: chemical and mineral (or physical). Chemical sunscreens absorb UV radiation and convert it to heat, while mineral sunscreens (like those containing zinc oxide or titanium dioxide) physically block and reflect UV rays. Each type has its pros and cons, so choose one that suits your skin type and preferences.

Environmental Impact

Some chemical sunscreens contain ingredients like oxybenzone and octinoxate, which have been shown to harm coral reefs and marine life. To protect our oceans, opt for "reef-safe" sunscreens that do not contain these harmful chemicals.

Sun cream Isn't Just for Sunny Days

Up to 80% of UV rays can penetrate clouds, meaning you can still get sunburned on a cloudy day. Snow, sand, and water also reflect UV rays, increasing your exposure. Make it a habit to apply sunscreen daily, regardless of the weather.

Sunscreen and Vitamin D

There’s a common concern that sunscreen use can lead to vitamin D deficiency since it blocks UVB rays, which are necessary for vitamin D production. However, most people still get enough UV exposure for vitamin D synthesis through incidental sun exposure. If you're concerned, you can also get vitamin D from dietary sources and supplements.

Water-Resistant, Not Waterproof

No sunscreen is truly waterproof. Water-resistant sun creams are labelled as such because they maintain their SPF protection for 40 to 80 minutes of water exposure. Always reapply after swimming or sweating.

Application Techniques Matter

For maximum effectiveness, apply sunscreen to dry skin 15-30 minutes before going outdoors. Don’t forget easy-to-miss spots like the ears, back of the neck, tops of the feet, and the part in your hair. Spray sunscreens should be rubbed in to ensure even coverage and to avoid inhalation.

Understanding the intricacies of sun cream can help you better protect your skin and make informed choices about the products you use. Remember, consistent and correct use of sun cream is key to preventing sunburn, premature ageing, and skin cancer. Stay sun-safe and enjoy your time outdoors!