Guide to Sunscreens

Guide to Sunscreens

Reviewed by Dr. Kate Shuster, board-certified dermatologist at Galen Dermatology

You need to protect yourself from the sun 365 days a year—even on cloudy days! Choosing the right sunscreen can help you protect your skin, reduce the risk of skin cancer, and prevent early skin aging caused by the sun. Here is our guide to selecting the right sunscreen!

Selecting Sunscreen

  1. Broad Spectrum – Sunscreens with this label mean that they protect the skin from UVA and UVB rays both of which can cause skin cancer.
  2. SPF – Make sure your sunscreen has an SPF, or Sun Protection Factor, of 30+ which filters out about 97%. Higher SPF does give more protection, but the higher you go, the difference of protection becomes smaller. No sunscreen protects you completely.
  3. Water Resistant – Remember, water-resistant does not equal waterproof. Therefore, you must re-apply at least 2 hours and more often if you are swimming or sweating.
  4. Physical v. Chemical – There are pros and cons of both physical and chemical sunscreens so it is important to know the difference so you can decide what is best for you and your family.
    • Physical sunscreen sits on your skin like a shield deflecting the sun’s rays and is also called sun block. They use mineral-based ingredients such as zinc oxide and titanium dioxide to block UV rays. They do come off easily so more frequent application is required. If you have sensitive skin, opt for the physical sunscreen, which is safe for use on babies, during pregnancy, and if you are prone to heat-activated skin conditions like rosacea.
    • Chemical sunscreen, on the other hand, is more like a sponge and absorbs the sun’s rays to change them into heat which is then released from the skin. Chemical sunscreen is thinner and therefore easier to rub into your skin. However, it is more likely to irritate skin, clog pores, and increase breakouts on acne-prone skin. 


Applying Sunscreen

  1. Everyone should be applying sunscreen. Even though melanin in the skin can absorb some UV rays before causing damage, it will not prevent all damage or limit exposure.
  2. Check expiration date before applying. Do not use sunscreen that is older than 2 years after it was manufactured.
  3. Apply sunscreen every day – even on cloudy days! 
  4. Most adults need about 1 ounce or 2 tablespoons of sunscreen to fully cover their body. Thin, light-weight, and light-colored fabrics are more likely to allow sunlight to filter through to your skin. Make sure to apply all areas your skin may be exposed. Do not forget your feet, neck, and ears!
  5. Re-apply every 2 hours at least and more often if you are swimming or sweating.


Looking for safe, recommended sunscreen products? Use Skin Cancer Foundation’s sun protection product finder: 


At Galen Dermatology we recommend and sell EltaMD sunscreen products. This brand offers a variety of sunscreens formulated for all skin types and lifestyles. Call us (423) 954-9017 for more information or come by to get your sunscreen and start protecting your skin today!