As the weather gets warmer, you’re probably thinking about being outside more. And this means you should be thinking more about wearing sunscreen. But the huge range of options for sunscreen can be overwhelming. What SPF should you get? What does “broad spectrum” mean? Should you get a spray or a cream? Use this post as a guide to help you understand the basics of sunscreen so you can prevent skin cancer and sun damage.
SPF stands for sun protection factor. It measures how much protection your skin gets from the harmful UVB rays that cause sunburn. The higher the number SPF, the more protection your skin will have. When you use a sunscreen with an SPF of 15, you will get 1 minute of UVB rays for every 15 minutes you spend in the sun. That means, that if you spend an hour in the sun wearing sunscreen with SPF 15, it is like spending 4 minutes unprotected. In terms of percentages, SPF 15 blocks about 93% of the sun’s rays, SPF 30 filters out about 97%, SPF 50 blocks 98% and SPF 100 blocks 99%. So, a good takeaway from these numbers is that just because the SPF number doubles, the amount of protection does not double. Also, the higher SPF you go, the smaller the difference in protection becomes. Getting a sunscreen with an SPF 100 is not going to offer significantly more protection than one with an SPF 50. Also, a higher SPF does not mean you can stay out in the sun longer without reapplying. So, what SPF should you use? Dermatologists recommend that you wear a daily sunscreen that has an SPF of at least 15. If you are going to spend any prolonged time in the sun, even when going about your daily activities, you should bump up the SPF to at least 30. You don’t need to go much higher than SPF 30 to get most of the UVB rays filtered out. However, remember that no sunscreen can block all of the harmful UV radiation from the sun.
The UV radiation from the sun is made up of multiple types of rays, UVA, UVB and UVC. About 95% of the UV radiation that hits the earth is UVA radiation. This is a lower energy radiation, but is still responsible for sun damage on the skin, especially the sun damage that causes premature aging. UVA rays can also penetrate glass. UVB radiation makes up the other 5%, but is higher energy and so, more damaging. It is the UVB radiation that causes sunburns. A broad spectrum sunscreen filters both UVA and UVB rays. Look for ingredients like zinc oxide, avobenzone & titanium oxide in your sunscreen if it is labeled as broad spectrum.
The PA rating system, developed in Japan, is starting to get used more in the US. The PA factor measures how much UVA radiation is blocked by the sunscreen and goes from “+” to “++++”. The more “+’s” on the rating, the more protection it offers from UVA rays. You can use this rating system plus the SPF to help you pick an effective sunscreen.
There are two major categories of sunscreen. Chemical (also called organic) and mineral (also called physical and inorganic). Mineral sunscreen sits on top of the skin and absorbs the sun’s UV rays, keeping the rays from hitting the skin. The primary ingredients in mineral sunscreens are zinc oxide and titanium dioxide. Chemical sunscreens are made of organic, carbon based compounds that are absorbed into the skin. Once UV rays hit the skin, the sunscreen converts the UV energy into heat, which doesn’t hurt the skin. There are reasons why you might want to choose either. Mineral sunscreens tend to be better for children and people with sensitive skin (they are less likely to cause an allergic reaction) and for those who have melasma. You might also feel more comfortable with a skin product that isn’t absorbed into your body. Mineral sunscreen starts working right away, while you have to wait for a chemical sunscreen to be absorbed and start to be effective. Many mineral sunscreens leave a white film on your skin once you have applied it, but because of advances in sunscreen formulations, there are new, physical sunscreens that don’t leave any residue. Certain chemical sunscreen ingredients (such as oxybenzone) have been found to damage coral reefs. So, if you’re swimming in an area that has coral reefs, you might want to stick with a mineral sunscreen. The benefits of chemical sunscreens are that they don’t leave a chalky residue behind, you don’t need to reapply as often (although every 2 hours is still recommended), and they tend to be better for people with acne-prone skin. If you’re still not sure which kind of sunscreen to get, you can find sunscreens that combine both physical and chemical ingredients.
In terms of offering better protection, it doesn’t really matter what form the sunscreen comes in, as long as you are applying it correctly. Don’t use spray sunscreens on the face, as inhaling them can be harmful. And make sure to use enough spray so that your skin glistens -- it’s easy to under-apply spray sunscreen. Stick sunscreen is a convenient way to keep your sunscreen with you in your purse and to easily apply to your face and to wiggly children.
Most people do not apply enough sunscreen. You should use 1 oz (a shot glass or palmful) of sunscreen for an adult’s face, neck, arms and legs). This does not include the amount you should use on your abdomen if you are not fully covered with a shirt. The Skin Cancer Society suggests that a family of four should use one four-ounce bottle of sunscreen during a long day outdoors, when reapplying correctly. Don’t forget the harder to see and reach areas, like the tops of and behind your ears, the scalp (where you part your hair), where your clothing may shift, behind your knees and the tops of your feet and toes. And wear a lip balm with an SPF of at least 15. You should apply sunscreen before you head outdoors. It takes about 15 minutes for your skin to absorb the sunscreen so it can protect you. You should also re-apply every 2 hours. If you are sweating or swimming, re-apply immediately after stopping your activity. There is no waterproof or sweatproof sunscreen -- only water-resistant. Look on the bottle of your sunscreen to see how long your sunscreen will remain water-resistant. If you are going to be swimming or exercising for longer than the allowed time, re-apply after the stated time limit.
As you go about choosing the best sunscreen for you, there are a few pieces of information that you should know about sunscreen. The first is that while you may only think about sunscreen when you’re headed to the beach or pool, you should be wearing sunscreen daily and year-round. Sun damage happens during your daily exposure to the sun, in cold and warm weather, in the winter and the summer, and anywhere on your body that is exposed to the sun. You should also know that sunscreen should not be your first line of defense in protecting your skin. You should first limit exposure to sunlight by staying in the shade, wearing sun-protective clothing (hats, sunglasses, long sleeved shirts, and pants), and getting out of the sun whenever you can. The American Cancer Society warms that sunscreen is a filter -- it doesn’t block all harmful UV rays. As such, sunscreens should not be used as a way to stay in the sun longer, but as a protective measure for times when staying in the shade or wearing protective clothing are not available as your first options.
Don’t get bogged down by all of the sunscreen choices. Most sunscreens are effective tools in skin cancer prevention. The most critical piece of advice in choosing sunscreen is: pick one that is SPF appropriate and broad spectrum -- and wear it daily with the recommended re-applications. You won’t know if you like a particular sunscreen or if your skin is sensitive to it until you try it.
Contact Vanguard Dermatology in the greater New York City area. The experienced dermatologists at Vanguard can perform skin cancer screenings, provide skin cancer treatment and advise you in the best skin protection methods.