PORTLAND, Ore. (KOIN) — The number one cancer among adults between 25 and 29 is melanoma — a deadly form of skin cancer.

A big factor is getting too much sun with little to no sunscreen.

Some people say they don’t like to wear sunscreen so they can can get more vitamin D. According to doctors, that’s a bad idea — you can get plenty of extra vitamin D from food and supplements.

There’s a lot more to sunscreen that people need to know.

One in 5 Americans will get skin cancer — the highest-growing rate of cancer for people in their 20s and 30s.

Skin cancer among men is most commonly found on their backs. For women, it’s the back of the legs.

To protect your skin from harm, you want a broad spectrum lotion that protects from UVA and UVB rays. Doctors say SPF 15-30 will work.

SPF 15 blocks 93% of rays and SPF 30 blocks 97%.

Put sunscreen on 30 minutes before

Re-apply every 2 hours

Keep infants out of sun

Put plenty of sunscreen on

“This is one of the biggest mistakes, not putting on enough. It should be one ounce per person,” dermatologist Phoebe Rich said.

Sunscreen should be reapplied every 2 hours. Water resistant varieties are good for 40 minutes in the water. Sunscreen should be applied 30 minutes before exposure, 15 at the very least.

You may be worried about chemicals often found in sunscreens — but many natural products work as well, just in different ways.

“A real sunscreen absorbs the rays and keeps them from getting through,” Rich said. “But a chemical-free product is reflective, provides an opaque masque that reflects it back.”

Because of those harmful chemicals babies under 6 months should not wear sunscreen. Doctors say keep infants out of the sun.

Spray sunscreens are easy to apply, but aren’t as effective as lotions.

“The sprays are not as effective as lotions since they often don’t cover all of your skin,” Rich said. “But at the same time, the most effective one is the one you’ll use.”