Do you need SPF 15, 30, or something higher?
The sun does so many things well. It warms us up, helps plants grow and powers new technologies. But it can also harm our skin if we aren’t careful. No matter what time of year it is, it’s important to keep your skin safe in the sun. Sun protection factor, or SPF, in sunscreen can help you do just that. Learn more about why sunscreen is so essential and what SPF to use to best protect your skin.
How SPF protects your skin
Sunlight produces ultraviolet radiation. This radiation is a type of energy that comes in two forms: UVA and UVB light. UVA light affects your skin’s deeper levels. It can cause you to develop wrinkles and other signs of aging. UVB rays damage the surface layers of your skin. They cause redness, sunburns and even blisters.
SPF is a way of rating sunscreens. It describes how much protection each sunscreen can provide against UVB radiation. Some types — called broad-spectrum sunscreens — can shield your skin against the effects of both UVA and UVB radiation. When you look at sunscreen bottles, you’ll notice numbers on them that tell you the level of SPF the sunscreen offers.
While SPF describes how well sunscreen protects your skin, the ingredients in the sunscreen are what actually protect you. There are two main types of sunscreen:
- Chemical sunscreens have ingredients that absorb UV light and release it back out of your skin.
- Physical sunscreens are made with extremely small metal or mineral particles that block the light from reaching your skin and reflect it away.
Is a higher SPF level better?
SPF levels start at 2 and go up to 100. What exactly do these numbers mean? They tell you how long you can stay in the sun without getting a sunburn. Multiply the number of minutes it takes you to get a sunburn by the SPF number. This tells you the number of minutes you can stay in the sun with one application of sunscreen.
Most people can be in the sun for about 10 minutes without sunscreen before their skin starts to burn. Using the equation above:
- SPF 15 protects you for 150 minutes.
- SPF 30 protects you for 300 minutes.
- SPF 50 protects you for 500 minutes.
SPF 30 blocks about 97% of UVB rays, and SPF 50 blocks about 98% of UVB rays. As SPF numbers increase from there, they don’t provide a big difference in protection. SPF levels over 50 aren’t much more effective, and they can give you a false sense of security. You should still try to stay in the shade and wear sun-protection clothing.
What SPF level do I need?
SPF 15 vs. SPF 30 vs. SPF 50 — which one should you use? Most people should start with SPF 30. If you have very fair skin, SPF 50 sunscreen is ideal. You likely won’t need anything higher than that.
Sunscreen becomes less effective after you’ve spent about two hours in the sun, and that’s if you aren’t sweating or swimming. Be sure to reapply it often when you’re outside — use at least 2 tablespoons’ worth of the lotion to cover your whole body. You should also wear sunscreen if you’ll be outside on a cloudy day. The radiation can still affect your skin.
Spreading on the SPF is a great way to start protecting your skin. Visit mercy.com to make an appointment with a primary care doctor or specialist. We’ll help you learn all kinds of helpful ways to stay safe in the sun!
Interested in more stories like this? Our Summer Survival Guide is full of healthy living tips to start your summer right. Learn more here.