Dr. Sheu, MD, FAAD is a board-certified medical dermatologist. She enjoys treating patients of all ages and particularly enjoys getting to know the families and friends of her patients. She does not practice cosmetic dermatology (which focuses on skin beauty rather than skin health).


Dr. Sheu practices at Valley Medical Center's Maple Valley clinic on Maple Valley-Black Diamond Road. The reception desk is shared with Urgent Care. Please note, the clinic has moved and Valley Medical Center no longer offers dermatology services in Covington.

Choosing a Sunscreen

Summer is just around the corner, and as the temperatures rise, so does the need to protect your skin from the harmful rays of the sun. Sunscreen is an essential tool in your arsenal when it comes to protecting your skin from UV damage, but with so many different types and brands on the market, it can be challenging to know which one to choose. Here are some thoughts to guide you in the selection process:

1. Check the SPF level:

One of the most important things to consider when choosing a sunscreen is the SPF level. SPF stands for Sun Protection Factor, and it measures how well a sunscreen protects against UVB rays. UVB rays are the type of radiation that causes sunburn and can lead to skin cancer. The higher the SPF level, the more protection you will receive against UVB rays. A sunscreen's SPF rating is based on laboratory use conditions in which a specific amount of sunscreen (2 mg/cm2) is applied to the skin (source). 

In laboratory use conditions: 
  • SPF 15 blocks 93 percent of UBV rays
  • SPF 30 blocks 97 percent of UBV rays
  • SPF 50 blocks 98 percent of UVB rays
  • SPF 100 blocks 99 percent of UBV rays
The American Academy of Dermatology (AAD) recommends that you use a sunscreen with an SPF of at least 30. In laboratory use conditions, there is little evidence to suggest that sunscreens with an SPF higher than 50 provide any additional benefit. However, in actual use conditions, SPF sunscreens with a higher rating provide better protection against sunburns (source).

2. Choose a broad-spectrum sunscreen:

While SPF measures protection against UVB rays, UVA rays are also harmful and can contribute to skin damage and aging. A broad-spectrum sunscreen provides protection against both UVA and UVB rays. Look for sunscreens that are labeled "broad-spectrum" to ensure that you are protected against both types of radiation.

3. Consider your skin type:

Different sunscreen formulations may work better for different skin types. For example, if you have oily skin, you may want to look for a lightweight, oil-free sunscreen. If you have dry skin, you may want to look for a moisturizing sunscreen. If you have sensitive skin, look for a sunscreen that is fragrance-free and formulated for sensitive skin.

4. Choose the right format:

Sunscreen comes in many different formats, including lotions, creams, sprays, and sticks. Choose the format that works best for your needs and preferences. For example, a lotion may be easier to apply to large areas of skin, while a stick may be more convenient for on-the-go touch-ups.

5. Apply correctly and don't forget easy-to-miss sites:

No matter which sunscreen you choose, it is essential to apply it correctly to ensure that you are getting the full benefit. Apply sunscreen generously to all exposed areas of skin, including your your ears and the tops of your feet in the spring and summer.

Don't forget to protect your lips with an SPF-containing lip balm as well. 

It is essential to remember that no sunscreen (even an SPF 100 broad-spectrum version) can provide 100% protection, so it is still crucial to take other sun-protective measures, such as seeking shade and wearing protective clothing.