The more sun you’ve been in over your whole life, the more wrinkles you’ll likely have on your face as you get older—and guys tend to have more wrinkles than women.

Women tend to get darker patches on their face more than men, especially after menopause, and it’s worse if they’ve been in lots of sun—but it’s not about how many total hours they’ve spent outside over their whole life.

Spending too much time in the sun is the biggest outside cause of wrinkles and aged-looking skin—more sun means more damage, and longer exposure makes it worse.

Men tend to have more wrinkles on their faces than women, even if they’ve spent the same amount of time in the sun.

Spending too much time in the sun over the years is why most wrinkles, sagging, and sunspots appear on your face—sunlight breaks down the skin’s support system like collagen and elastin, and creates harmful free radicals.

The more wrinkles you have on your face, the more sun you’ve been exposed to over your life—and that might help doctors guess how likely you are to get skin cancer, without needing any blood tests or scans.