Your Butt Is Proof That You Should Wear Sunscreen Every Day, Says Dermatologist

By

The sun is a great friend. You literally couldn’t live without it. But, like any good relationship, it’s important to have boundaries. So in your daily intercourse with the sky god, wear protection.

This truth — that you should wear sunscreen every day, for serious — gets repeated in every issue of every lifestyle or fitness magazine. But it really came home for me in conversation with dermatologist Dr. Diane Madfes, who serves as an assistant clinical professor at Mount Sinai Hospital. I asked if my skin, now at age 29, would look different at 39 depending on whether or not I applied sunscreen every day.

It’ll look “significantly different,” she said, instilling the fear of god in me. If I dutifully wear sunscreen every day, in ten years my skin will have fewer brown spots, fewer wrinkles, less sun damage, and I will be at lower risk for skin cancer. For proof, she invited me to look at my own butt. “A good way to reassure yourself (and readers) is to look at areas that are photoprotected by clothes, i.e. the buttocks,” she said. “The skin in this area is smoother, tighter, with better elasticity.”

It has to do with the mechanics of aging, she explained. Part of why getting exquisitely tanned in the summer right now (nice) is so dangerous for you later (not so nice) is that sun damage suppresses your immune system, making it easier for skin cancer to grow. There’s also the curious case of free radicals: Contrary to their name, they are not awesome. Free radicals are the anarchists of your skin chemistry, killing cells and activating enzymes that break down collagen and elastin, the skin ingredients that keep your face taut, supple, and marketably young, and the cumulative damage of which results in skin aging. With that come fine lines (not from wisdom, from the sun), and as your skin gets thinner, the blood vessels underneath become more exposed. “If you do protect when you’re young,” she says, “you’ll have it for your lifetime.”

In this way, skin care is kind of like personal finance: Saving money isn’t cognitively complex, but it takes a lot of discipline to do actively, so you should probably automate as much of the process as possible. Similarly, you want to make installing the habit of skin care into your life as frictionless as possible. As long as it blocks both UVA rays (which get into the deepest layers of your skin) and UVB rays (which burn the top layers) and has an SPF of 30 or above, find whatever formulation you like to have on your skin. It could be a cream, gel, lotion, or stick. And Dr. Madfes’s biggest tip is to make it routine: “When you brush your teeth, put your sunblock on.” And don’t forget your ears and neck — they just take another moment.