Sunscreen (SPF) is the most essential step in your routine.
On one hand, wearing sunscreen daily can keep you looking years younger, and on the other, it can save your life. No matter how much money you’re currently spending on other skincare and beauty products, if you’re not applying sunscreen, you’re missing the most essential step to healthy skin. To help make sure you’re always covered, here's a guide to help you find the perfect sunscreen for you.
Why is sunscreen important?

Sunscreen protects against the sun’s ultraviolet rays. Scientific evidence shows that using sunscreen, keeping out of direct sunlight, and wearing protective clothing can be effective in preventing skin cancer as well as short term and long term damage to the skin. During peak hours, when the sun is at its most powerful (between 10am and 3pm), it’s better to stay inside or in the shade if you can, to make sure your skin is protected from those harmful rays. 

Dermatologists recommend that you choose a sunscreen with at least SPF 30, which blocks 97% of UVB rays. Higher SPF sunscreens will block a higher percentage, but no sunscreen will block 100% of these rays. Also keep in mind that even though SPF should in theory correspond to how long before reapplication, the American Academy of Dermatologists, recommends still reapplying sunscreen every two hours.

FAQs:

What does SPF mean?

SPF stands for Sun Protection Factor. This pertains mostly to UVB rays, which are the ones that result in sunburns. Rather than penetrating the deeper layers of the epidermis, UVB rays generally burn the outer, superficial layers of the skin. These rays are the ones that play a strong part in the formation of skin cancer. So, it’s important to adequately protect yourself from them. This is where SPF comes in.

What is the best ingredients to look for in sunscreens?

Sunscreens are divided into two different categories: physical and chemical. A common misconception is that physical sunscreens contain natural ingredients that are better for your health. The reality is that bothphysical and chemical sunscreens contain chemicals. Physical sunscreens usually use titanium dioxide or zinc oxide, while chemical ones use a variety of ingredients, like aoxybenzone, avobenzone, homosalate and octinoxate.

What's the difference between UVA and UVB rays?

Every time we go outside, we’re exposed to two different types of harmful UV rays: UVA and UVB. UVB rays are the ones that result in you getting that awful sunburn. UVA rays penetrate the deeper layers of the dermis and can cause premature aging. Long term exposure to UV radiation increases the formation of free radicals. As a result, they cause extensive damage both physically and internally.

What is the difference between physical and chemical sunscreens?

Nothing really. Despite popular belief, physical and chemical sunscreens actually work in the same way. They form a protective film on the skin that absorbs UV light and turns it into heat. Physical and some chemical sunscreens, also reflect and scatter the incoming UV light. Both sunscreen types work effectively at protecting you from harmful UV rays.

Should I apply sunscreen before or after moisturizer?

Most sunscreens contains silicones that form an occlusive, protective layer on the skin. To get the most from your SPF, you’ll want to apply it after your moisturizer. This is to avoid disturbing your SPF or decreasing its protection in any way. But, you can also use a moisturizer and SPF combination, which takes care of that in one simple step.

How much sunscreen do I have to apply?

According to the American Academy of Dermatology, you should use at least one teaspoon of sunscreen on your face. People tend to go light with their sunscreen because they either don’t like the texture or the formulation might mess up their makeup. Instead, it’s best to take a “more is more” approach and apply more than you think you need. As for the body, the AAD suggests “one ounce, enough to fill a shot glass,” to protect you from UV rays. Remember to reapply throughout the day for long-lasting protection.

If I have acne, sunscreen will make skin worse?

Nope. While it can be a hassle to find sunscreen formulas that work with acne-prone skin, rather than skipping sunscreen altogether, which would actually cause more damage, Sadick suggests “choosing a formulation that is light, water-based, and avoids any products that contain heavy oils like coconut, beeswax, and cinnamon oil.”

How long do I need to wait after applying sunscreen before going outside?

Most sunscreens will suggest applying 10 to 15 minutes before heading out the door. This idea perpetuates the myth that you have to apply your sunscreen earlier so it has time to “activate.” But, this has less to do with activation and more about creating an even layer of sunscreen on the skin.

Your sunscreen doesn’t actually have to activate—it works from the very moment that you apply it. But, in order for an SPF to do its job, you want to allow it to create an even film on the skin. The more even your application, the more complete protection from UVA and UVB rays.