How Much Sunscreen Should I Use?

At the 10th Annual Focus on Melanoma Conference, Penn Dermatologist Chris Miller, MD, said, “If you haven’t gone through a bottle of sunscreen throughout the summer season, you didn’t use enough sunscreen.”

Right now, the beginning of the summer, is a great time to refresh your knowledge about SPF, sunscreen and how to apply sunscreen correctly.

What is SPF?

The Sun Protection Factor (SPF) displayed on the sunscreen label ranges from 2 to as high as 50 and refers to the product's ability to screen or block out the sun's harmful rays. For example, if you use a sunscreen with an SPF 15, you can be in the sun 15 times longer that you can without sunscreen before burning.

What SPF should I choose?

It’s recommended you use a sunscreen with an SPF of 15 or greater for all skin types, year-round. Those with fair skin should choose a sunscreen with a higher SPF. It’s also important to choose a “broad-spectrum” sunscreen that protects against UVB and UVA radiation. Sunscreen that is waterproof or water-resistant is important if you will be sweating or participating in water activities.

How much sunscreen do I need? Where should I apply it?

You should apply sunscreen to all areas of the body that will be exposed to the sun for more than 20 minutes at a time. One ounce should be able to cover your entire body. Today, most facial moisturizers contain sunscreen and can be worn under makeup. It’s important to use sunscreen year-round (even in the winter), and in all types of weather as the sun’s rays can penetrate clouds.

It’s also important to remember to apply sunscreen to the ears, feet (if bare feet or wearing sandals), and on the hands. Chap stick with SPF is also great protection for the lips.

How often should I apply sunscreen?

Sunscreen should be applied in the morning, and reapplied after swimming or perspiring heavily. Sunscreen begins to lose its effectiveness after 80 minutes in the water, so make sure to reapply once you have towel-dried.