A new review finds that nearly four in five, or about 80 percent, of sunscreens offer inadequate skin protection or contain potentially harmful ingredients. With Memorial Day weekend kicking off the summer season it is essential to be protected from the harmful rays of the sun.

The Environmental Working Group (EWG) just released its 19th annual Guide to Sunscreens,  which reviewed 2,204 sun protection factor, or SPF, products. Of those, only 498 products meet EWG’s strictest criteria for effectiveness and safety.

According to the Skin Cancer Foundation, one in 5 Americans will develop some form of skin cancer by age 70, so it is vital to learn about the best ways to protect your skin.

“Wearing any sunscreen is much more important and offers better sun protection for your skin than not applying anything,” said EWG’s acting science officer David Andrews. “But not all sunscreens are created equal. EWG’s guide is a valuable and trusted resource that consumers can turn to every year to find the sunscreens that offer strongest broad-spectrum protection without the use of concerning ingredients.”

Sunscreen helps prevent sunburn, premature aging and skin cancer. But some products, about 36%, have hidden fragrance added to their formula, which could include allergens or hormone-disrupting chemicals. Others boast SPF “boosters,” which claim to enhance their broad-spectrum protection against the sun’s ultraviolet A and B rays. Unfortunately, these products are underregulated in the U.S. and may contain butyloctyl salicylate, or BOS, which may be troublesome.

Spray sunscreens continue to be popular, representing 26% of the products in the guide, but EWG experts say these can be risky as their ingredients could be inhaled and they are less effective than lotions.

Jilly Senk, EWG’s associate science analyst, tells Newsmax that the updated guide helps consumers make informed choices. “It’s essential to wear sunscreen,” she asserts. “Any sunscreen is better than none when it comes to protecting your skin. That being said, we prefer the mineral-based sunscreens, those using zinc oxide or titanium oxide. These minerals are the only active ingredients currently generally recognized as safe and effective for sunscreens by the FDA.”

Mineral-based products sit on top of the skin and reflect UV rays, rather than being absorbed by the skin like chemically-based sunscreens.  Senk says that sunscreen should be applied 15 to 30 minutes before going out in the sun and then reapplied every two hours or immediately after swimming or sweating. For full-body coverage, adults should use about one ounce — about the size of a shot glass. For the face, apply a nickel-sized dollop, according to the Skin Cancer Foundation.

“Consistency and coverage are key,” says Senk. “Don’t forget easy-to-miss spots like ears, your scalp, the back of the neck and the tops of your feet.”

Remember, no matter how much sunscreen you apply, the SPF should be 30 or higher for adequate protection – and ideally 50 or higher for extended time spent outdoors. Be sure your sunscreen says “broad spectrum” on the label, which means the product protects against UVA and UVB rays.

The EWG’s Guide to Sunscreens offers important lists, including a selection of the top-rated recreational sunscreens, the safest for kids and babies, moisturizers with SPF and lip balms – those EWG scientists ranked the highest for their overall protection from UVA and UVB rays and other factors.