How to Choose a Sunscreen | South Shore Moms

How to Choose a Sunscreen

Written By: Susan Hoover, FNP-C

Brought to You By South Shore Health

As the days get longer and the sun gets stronger, we all end up in the sunscreen aisle at our favorite store and think, “OMG! Sunscreens! How do I pick one? Which one is the best? What does everything mean on the label?”  

It’s easy to feel overwhelmed because we all know how important sun protection is to our health. While the best way to avoid the damaging rays of the sun is to avoid direct exposure—especially between 10 AM and 2 PM when it’s strongest—that’s not always doable. Wearing sunscreen is a critical step to preventing sunburn and skin cancer. There are so many options it can be hard to know which sunscreen is the right one for you. 

Before we get into choosing a sunscreen, let’s review why we need it in the first place. The sun emits ultraviolet (UV) radiation. This radiation damages the DNA of our skin cells—which can lead to cancer. There are three types of UV rays: UVA, UVB, and UBC. The ones to remember when it comes to skin damage and skin cancer are UVA and UVB. (To learn more about the types of UV, click here.)

Okay, now let’s try to clarify all the confusion around sunscreen.  

Understand the two types of protection

There are two types of sun protection: organic and inorganic. The inorganic (sometimes called “physical” or “mineral”) type is a blocking agent that prevents most of the sun’s UV rays from penetrating the skin to cause a burn. Think of that thick white cream that lifeguards use on their noses, which is called zinc oxide. The organic (or “chemical”) type uses chemicals, such as oxybenzone, to absorb most UV rays before they damage your skin cells. 

Consider the SPF

The Sun Protection Factor (SPF) noted on the bottle of sunscreen is a rough guideline that tells you how much longer than normal you can be out in sun without getting burned by UV rays. (Remember factors in high school math?) 

For example, let’s say you can normally be in the sun without sunscreen for about 10 minutes before getting a sunburn. If you put on sunscreen with an SPF of 30, you should be able to stay out in the sun 30 times longer (about 300 minutes) without getting burned. For most people, an SPF of is 15 or greater should be fine when applied correctly. (More on that later.)    

Broad spectrum is best

Remember the two types of UV rays I mentioned earlier? Not every sunscreen protects against both kinds.

To minimize your skin damage, look for broad spectrum sunscreens, which protect against both UVA and UVB radiation.

Invest in water- and sweat-resistant sunblock

This is especially important if you are going to be in the water or doing activities outside. In order to call itself water- or sweat-resistant, the sunscreen has to maintain its SPF qualities for 40-80 minutes while swimming or doing an activity. Water and/or sweat resistance sunscreen will work best if applied prior to beginning activities and allow to dry and absorb into the skin.  

Apply it correctly

No matter what kind of sunscreen you buy, it won’t work if it’s not applied properly.

If you’re using a lotion-like sunscreen, adults need a full ounce (about a shot glass) of sunscreen for their entire body. Be generous!

Don’t use it on infants

Babies six months of age or younger should be kept out of the sun entirely.  

Check the expiration date

All sunscreens expire, and won’t be effective after a date. Always refresh your supply when needed.

Protecting your skin today will make a huge difference as you get older. 


To learn more about Health Express, part of South Shore Health, click here.

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