All You Need To Know About Sunscreen


Using sunscreen is like eating your vegetables. We know it is good for our health, but we don’t always know exactly why and, not to mention, how to properly use it:

What exactly are UV rays and what does SPF really mean anyway?

Allow us to demystify everything you need to know about protecting your skin from the sun, just in time for summer vacation.

What Are UV Rays?

Ultraviolet Rays (UV rays) are potentially harmful rays that are emitted from the sun. While there are actually many types of UV rays, we are most concerned with UVA and UVB rays since they are correlated with skin cancers.

All sunscreens protect against UVB rays because they are the main cause of sunburns and skin cancers. However, UVA rays can also contribute to skin cancer and premature aging. That’s why it is important to choose products that are “broad spectrum,” which means they protect against both UVA and UVB rays.

What Does SPF Mean?

Sun Protection Factor (SPF) comes into play because it measures how long the sunscreen will protect you from UVB rays (but not UVA rays).

According to the American Cancer Society, you should choose an SPF of 30 or higher. In fact, the FDA has issued a requirement that anything containing SPF 15 or lower needs to have a warning label similar to non-broad spectrum sunscreen.

The higher the SPF number, the more protection it offers:

However, keep in mind that as the SPF number increases, its efficacy is only marginally better. For example, SPF 15 filters out about 93% of UVB rays, while SPF 30 filters out about 97%, SPF 50 filters out about 98%, and SPF 100 about 99%. Currently, there is no sunscreen that offers 100% protection.

How Does Sunscreen Work?

Before we dive in, let’s clarify: sunscreen and sunblock are not the same:

As the name implies, sunblock actually blocks UV rays from reaching the skin whereas sunscreen does not. Instead, sunscreen absorbs the UV rays when they reach the skin.

The differences between sunscreen and sunblock lie in the ingredients:

Sunblock is typically made from mineral ingredients like titanium dioxide and zinc oxide.

Sunscreen, on the other hand, is made from chemical ingredients like benzophenones (oxybenzone), cinnamates (octylmethyl cinnamate and cinoxate), sulisobenzone, and salicylates.

Which Sunscreen Is Best For You?

The right sunscreen for you is the sunscreen you will use:

According to New York dermatologist Julie Russak, MD, “There is no real SPF number to determine whether a sunscreen is right for you, though we usually recommend at least SPF 50. I always convey to my patients that even if you apply SPF 50 but do not apply enough of it, it is not as effective. There’s a significant drop-off in your perceived SPF coverage when applying less than the recommended amount.”

For your body, the FDA recommends applying a full shot glass-worth of sunscreen. “In reality, none of us do this and thus rarely apply the right amount of SPF,” says Dr. Russak. “Based on this fact, I ultimately recommend patients use the highest SPF available because you will most likely be applying less than the amount recommended.”

According to the AAD, most people only apply 25 to 50% of the recommended amount of sunscreen. It is important to apply to the tops of your lips, feet, neck, ears, and top of head (if you have thinner hair) and to reapply every two hours or more often if swimming or sweating.

Dr. Russak also advises being mindful of environmental factors that can contribute to how quickly you burn, like the altitude (the closer to the sun, the stronger the rays).

You also need to remember that water-resistant sunscreen is not the same as waterproof:

A truly waterproof and sweatproof sunscreen has yet to be developed. Water-resistant products cannot last a whole day and need to be reapplied at least every two hours.

While water-resistant sunscreen can last up to 80 minutes while sweating or swimming, it can easily come off from the water or even be rubbed off when drying yourself with a towel.

What Sunscreen Ingredients Should We Look For?

Dr. Russak recommends using a broad-spectrum mineral-based sunblock containing zinc oxide and titanium dioxide. “Mineral sunscreen is the best SPF for everybody,” she says, as it typically can contain less preservatives and other fillers and can cause less irritation (which makes them perfect for sensitive skin).

“For the face, use a lighter mineral SPF intended specifically for facial use, which will blend easier,” she says. “For the body, I recommend a mineral SPF in a spray form, especially for kids. I like Elta Md AERO for the body, it sprays white and you can see it on the skin. Kids can see it as they apply it, and so can I, before it blends into the skin and becomes invisible.”

What About People With Fair Skin?

“People with fair skin have a higher risk of developing cancerous and precancerous lesions and should seek more shade than most. It’s crucial for someone with fair skin to apply broad-spectrum SPF more often and avoid the sun when it’s strongest (from 12-3 PM),” says Dr. Russak.

What About People With Dark Skin Types?

“Those with dark skin often think they do not need SPF, or at least not as much, but this is absolutely not true,” says Dr. Russak. “People with dark skin are just as vulnerable to developing cancerous and precancerous lesions.

I often encounter patients of darker complexions who avoid sunscreen altogether because they fear they’ll look ashy or white post-application. What they may not know is not all sunscreens are made the same, and there are great options offering an invisible or a more universal finish such as, Revision Intellishade.”

What Is The Proper Way To Apply Sunscreen When Wearing Makeup?

“In the summer, I recommend applying sunscreen at home before leaving the house,” says Dr. Russak. “Apply on clean, dry skin and before putting on any makeup. Let the sunscreen absorb a little on the skin, while it forms a protective layer. Then, layer on the makeup on top of it.”

Why Is Sunscreen So Important?

About 90% of non-melanoma skin cancers are associated with exposure to UV rays from sunlight. And while UVA and UVB rays are directly linked to cancer, a lot of cases are preventable.

According to the Skin Cancer Foundation, daily use of an SPF can cut the risk of developing melanoma in half. In addition to cancer, UVA and UVB rays are also directly correlated with skin aging. The Skin Cancer Foundation reports that an estimated 90% of skin aging is caused by the sun.

Furthermore, sunscreen plays an important role in post-surgery healing. Because sunlight can cause darkening and discoloration around a scar, it is more critical than ever to wear sunscreen to help scars heal as properly as possible.

Wearing sunscreen every day, not just at the beach or beside the pool, is essential to our overall health. The sun emits harmful UV rays year-round and even on cloudy days.

In fact, snow, sand, and water can actually reflect the sun’s rays, making the need for sunscreen even stronger. And remember that sunscreens are designed to have a shelf-life of three years. If you have a bottle of sunscreen that it is past its expiration date, it is no longer effective and should be thrown out.

Always remember that sun exposure and UVA/UVB rays are directly linked to skin cancer, premature aging, and discoloration of scars, so the most important thing for skin care and your overall health is consistent and complete broad-spectrum sun protection.

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