What to Look for When Choosing a Sunscreen

By: Julie Neville, MD, FAAD 

When picking out a sunscreen to protect yourself from the sun’s harmful radiation, several factors you should look for include:

1. Broad-spectrum protection:  Look for a sunscreen labeled as “broad-spectrum” which means that it will protect from both ultraviolet-A (UVA) and ultraviolet-B (UVB) rays. Both types of rays contribute to skin cancer. UVA rays penetrate deeper into the skin causing premature aging while UVB rays stay in the top layers of the skin causing sunburn.

2. SPF (Sun Protection Factor):  Choose a sunscreen with a sun protection factor (SPF) of at least 30.  SPF indicates how well a sunscreen protects against UVB rays. For example, a SPF of 30 blocks approximately 97% of UVB rays.  Higher SPF sunscreens provide slightly more protection but no sunscreen will block 100% of UV radiation.  To receive the maximum protection, you should use about one ounce (the size that would fit inside of a “shot glass”) of sunscreen to cover your entire body. 

3. Water resistance:  Sunscreens do wash off if you are swimming or sweating. To be considered “water resistant” sunscreens must provide protection for at least 40 minutes while in water. While this is a helpful feature, we still recommend that sunscreens are reapplied every 2 hours while outside and even more frequently if you are swimming or sweating.  Sunscreens should be applied around 30 minutes before going into the sun. 

4. Skin type and sensitivity:  If you have sensitive skin, mineral sunscreens containing zinc oxide or titanium dioxide are generally well tolerated.  If you have acne-prone skin, look for a sunscreen labeled as “non-comedogenic.”  

5. Ingredients:  Sunscreens contain mineral blockers, chemical blockers, or both.  Mineral sunscreens physically block UV radiation and are less likely to cause skin irritation compared to chemical sunscreens.  They can appear whiter on the skin but do come in micronized or tinted formulations to help blend in with your skin tone.  Chemical sunscreens contain ingredients such as avobenzone and octocrylene and are considered safe and effective for most individuals.  

6. Formulation:  Sunscreens come in various formulations, including lotions, gels, creams, sprays, powders, and sticks.  Choose a formulation that suits your preferences and activities. 

7. Expiration Date:  Check the expiration date on the sunscreen to ensure its effectiveness.  Expired sunscreen may not provide adequate protection against UV radiation.  

Finally, remember that while sunscreen helps with UV protection you can further protect your skin by wearing sun-protective clothing, including a wide-brimmed hat and sunglasses, and avoiding mid-day sun exposure when possible.