Sunscreen Science: How to Choose the Right One

Ria Sharma
21 hours ago
5 min read

Did you know that having 5 or more sunburns can double your risk for melanoma, the most invasive type of skin cancer? Despite this startling statistic, the risk can be easily reduced through the power of sunscreen! These products protect you from the sun's harmful rays and the first of its kind was released in 1932 during World War II to protect soldiers. The need for sun protection remains incredibly prevalent today with a variety of sunscreen options available, but how do you choose the right one?

First, what is sun exposure and why is it harmful? The sun emits different types of light energy and one of these is ultraviolet (UV) radiation. There are 3 different UV rays: UVA, UVB, and UVC. While UVC rays are completely absorbed by the ozone layer, both UVA and UVB rays reach the Earth and can cause damage. UVA rays make up 95% of the UV radiation that passes through the atmosphere and maintain the same level of strength throughout the year during daylight. These rays are associated with tanning and skin aging as they deeply penetrate the skin, damaging cells' DNA. Contrastingly, the intensity of UVB rays fluctuates and is stronger at high altitudes, on reflective surfaces, and during late morning to mid-afternoon hours. These rays are associated with sunburn.

Despite the differences between UVA and UVB rays, their impact is equally damaging. Over time, UV exposure accumulates and increases one's risk for skin cancer. This is the most common type of cancer in the United States as 1 in 5 Americans develop it before they reach 70 years old. Sun exposure can also cause sunburn, pre-mature aging––where the skin becomes thick and leathery, and eye problems, such as cataracts.

Next, why is sunscreen so important? Sunscreens are products that are formulated to reduce UV exposure and its risks. Sun exposure impacts every single person and as such, sunscreen is for everyone, except for babies under 6 months old. Additionally, UV radiation is present during all daytime hours as 80% of radiation can still reach the Earth's surface despite rain, fog, or clouds. Hence, "daily sunscreen application is non-negotiable," as affirmed by dermatologist Dr. Vivian Bucay. At the very least, make sure to put sunscreen on the parts of your body that are exposed to the sun: face, ears, neck, arms, and legs. Although you can apply sunscreen while you're dressing for the day, make sure to also do so 30 minutes before you plan to go outside so the product can bind to your skin. However, the most significant detail to remember is reapplication. Sunscreens are often labeled with their Sun Protection Factor (SPF) which is how many times longer it would take the sun's radiation to redden the skin with sunscreen compared to without it. This means that no matter how high a sunscreen's SPF is, it will not be as effective after a certain amount of time. Thus, it is crucial to reapply every 2 hours and immediately after swimming or sweating.

Finally, what is the best sunscreen for you? Let's find out below:

To begin, take a look at the 'active ingredients' section on sunscreen. There are 2 main types: physical and chemical ingredients. Examples of physical ingredients are titanium dioxide and zinc oxide. They act as a shield to reflect and scatter UV rays. They also tend to leave a noticeable white case. On the other hand, chemical ingredients like avobenzone and octisalate are transparent and act as a sponge to absorb UV rays. These 2 types of ingredients are safe, and you may find sunscreens that combine them both. However, if you have sensitive skin, sunscreens with physical ingredients are less likely to cause skin irritation. It may also be worth it to avoid products with added fragrance for those with sensitivity.

Now, consider the sunscreen's labeling. It is of significance to utilize 'broad spectrum' sunscreen as these products will protect your skin from both UVA and UVB rays; sunscreens without this label are designed only for UVB radiation protection. SPF labels, as previously mentioned, come with different levels of protection. For daily usage and occasional sun exposure, it is best to apply sunscreen of at least SPF 30. If you plan on participating in outdoor activities, live close to the equator, or are at higher risk for skin cancer (family history or light-color skin, hair, and eyes), then make use of sunscreen that is SPF 50 or higher. At the very least, incorporate SPF 15 into your daily routine as it reduces the risk of developing melanoma, the most invasive type of skin cancer, by 50%. If you anticipate water activities or sweating, look for sunscreen that is labeled 'water resistant' and 'very water resistant' for up to 40 and 80 minutes, respectively, of effectiveness. For these water resistant sunscreens, make sure to reapply during the given time intervals and for all other sunscreens, reapply every 2 hours.

Additionally, assess yourself. If you have dry skin or it's during the winter months, you may want to use moisturizing sunscreen––look for shea butter, glycerin, and hyaluronic acid in the ingredients. If you have oily or acne-prone skin, consider taking advantage of an oil-free moisturizer––look for niacinamide, ceramides, and peptides.

Lastly, decide between spray or lotion sunscreen. The benefits of spray sunscreen are that it's quick, easy, and non-greasy. However, it doesn't evenly apply easily which can cause some product to be blown away in the wind and ultimately more of the spray will be used in the long run. One way to combat this is to spray sunscreen onto your palms and then massage it onto your body. Spray sunscreen can also cause allergic reactions and irritate the lungs if inhaled, so be careful to avoid the eyes and mouth. When taking into consideration lotion sunscreen, the benefits are that you'll be able to see where you're applying to and that these products are easier to find. Yet, lotion sunscreens are more expensive as they are of a thicker formula, so it takes longer to completely rub it in, and they leave a whitish tint. Despite this, lotion sunscreens are less likely to cause allergies and rashes. Also, the visible film left on your skin can be avoided by using tinted sunscreens. If you are applying lotion sunscreen to your entire body, squeeze about 1oz of product to completely cover the palm of your hand. If you are using lotion sunscreen specific to your face, use about ½ teaspoon of product. When deciding between these 2 types of products, lotion sunscreens are the recommended option, but spray sunscreens are still effective given diligent application.

Ultimately, it is clear that sunscreen is a crucial product that should be integrated into your daily life. That being said, no sunscreen will be able to filter 100% of UV radiation, so stay out of the sun whenever possible, wear sun-safe clothing, and UV-blocking sunglasses. Still, premature aging, sunburn, and skin cancer can be prevented by using sunscreen. Thus, start by looking at broad spectrum sunscreen that is of at least SPF 30 and go from there. In choosing the right sunscreen for you, consider your own lifestyle, skin type, and preferences.