Why does spf matter

In looking at all the research available, they found that sunscreen reduced the incidence of squamous cell cancer, but that it had no effect on basal cell cancer. What's more, "There are no direct data about the effect of sunscreen on melanoma incidence. Still, research is always evolving and newer studies are emerging that show sunscreen can curb melanoma risk, such as this long-term trial from Australia.

Fisher and many of his colleagues think we'll likely see more research moving in this direction since earlier studies may not have been conducted over a long enough period of time to capture the development of melanoma in people and the potentially protective effect of sunscreen. There are epidemiological studies which show that people who use sunscreen seem to get melanoma at a higher rate.

But just because the two findings are linked doesn't mean one causes the other. More probably, people who use sunscreen have more exposure to the sun's cancer-causing radiation and therefore, a higher chance of getting skin cancer. Sunscreen may also lull people into a false sense of security.

For example, this study of to year-old Europeans found that those who used sunscreen with a higher SPF stayed in the sun for a longer period of time than those who used lower SPF sunscreen. Another complicating factor: people who burn easily—ie.

And fair-skinned people are more likely to get skin cancer than their darker-skinned counterparts. UV exposure increases the risk for skin cancer among people with all skin types, but especially fair-skinned people.

Those who sunburn readily and tan poorly, namely those with red or blond hair and fair skin that freckles or burns easily, are at highest risk for developing skin cancer and would benefit most from sun protection behaviors. The incidence of melanoma among whites is 20 times higher than it is among blacks; the incidence of melanoma among whites is about 4 times higher than it is among Hispanics. So cause and effect are difficult to untangle. But remember: even if it turned out that the smelly lotion doesn't reduce the risk of deadly melanomas, that doesn't mean it's not an important part of protecting your skin from the sun's other harmful effects.

Sunscreen is recommended as one of several sun protection methods. Your objective should be avoiding cancer-causing and skin-damaging sunburns by any means, and there are other easy and cheap things you can do to stay safe, such as:.

This randomized trial conducted on Australian adults found no relationship between vitamin D deficiency and sunscreen use over the course of a summer. This review of the literature on UV-protection and vitamin D also suggested vitamin D levels didn't decrease in sunscreen wearers.

Sunscreen and sunblock: the words are used interchangeably, but if you want to get technical, sunscreen generally refers to lotion that protects your skin by a chemical process, while sunblock creates a physical barrier to literally block or reflect UV-rays. Compared to sunscreen, sunblock tends to be opaque and leave a white film on the skin. If you're now confused about what type of lotion to use, the Academy of Dermatologists takes a common-sense approach to the question: "The best sunscreen is the one you'll use again and again.

Our mission has never been more vital than it is in this moment: to empower through understanding. Financial contributions from our readers are a critical part of supporting our resource-intensive work and help us keep our journalism free for all. Please consider making a contribution to Vox today to help us keep our work free for all. Cookie banner We use cookies and other tracking technologies to improve your browsing experience on our site, show personalized content and targeted ads, analyze site traffic, and understand where our audiences come from.

By choosing I Accept , you consent to our use of cookies and other tracking technologies. It just means it will protect your skin for longer. And to learn more about protecting your skin, or any other health topic, contact the Health Information Center. The Health Information Center is a library staffed by medical librarians and certified health information specialists.

The Health Information Center can do research on any health topic and get the results to you for free. Contact them at or library utmck. There is also a large collection of health books covering a variety of topics, including the following:. Understanding melanoma : what you need to know.

When a loved one falls ill : how to be an effective patient advocate. The definitive guide to cancer : an integrative approach to prevention, treatment, and healing. Ideally, you should also apply sunscreen to your skin 30 minutes before going out into the sun.

SPF is short for sun protection factor. UVA rays contribute to the signs of aging in the skin, like wrinkles and sagging. UVB rays are more carcinogenic and often responsible for sunburns. For example, an SPF of 15 provides about 15 times more protection than just your normal skin without sunscreen.

An SPF of 50, then, would provide 50 times more protection than skin without sunscreen. You should avoid using sunscreen on babies under 6 months old. Sunscreen can be potentially harmful in young babies because they may be at greater risk of side effects from the chemicals in sunscreen. When choosing a sunscreen for your baby, choose one of at least SPF Most baby sunscreens are SPF Sunscreen lasts an average of two hours.

That means you should plan to reapply every two hours. For low exposure to the sun, a moisturizer or makeup with a base of SPF 15 built in is sufficient. There are many different types of sunscreen you can choose.

Read more about what to consider when choosing a sunscreen.