Sunscreen is commonly hailed as safe, essential body armor. It protects us from blistering sunburn, keeps our skin from wrinkling and helps guard against squamous cell cancer.

But the evidence is inconclusive as to whether sunscreens reduce the risk of basal cell cancer and melanoma, the most deadly form of skin cancer. Some scientists have accused dermatologists and the sunscreen industry of scaring Americans out of the sun’s powerful ultraviolet rays, which the body needs to generate vitamin D.

And although most of us assume that sunscreens are safe and effective, we could use some federal quality and safety standards. Four out of five name-brand sunscreens offer inadequate protection, according to the second annual sunscreen summary by the Environmental Working Group, a non-profit environmental research organization. Leading brands — Coppertone, Banana Boat and Neutrogena — were the worst offenders according to the group, which recommended 143 products at www.cosmeticsdatabase.com.

Still, as a fair-skinned, light-haired sun worshiper who has every other risk factor for skin cancer, I consider sunscreen an important tool. Here’s how to use it wisely.

Seek shade or make it. Don’t use sunscreens as a first line of defense against melanoma or a license to bask in the sun, said Robert J. Davis, author of “The Healthy Skeptic’’ (University of California Press, $21.95). Instead, stay out of the sun at peak hours — 10 a.m. to 4 p.m. — and “cover up with dark-colored clothing that’s made of tightly woven fabric or specially treated to block UV radiation,’’ Davis wrote.

The oxybenzone debate. The EWG recommends avoiding sunscreens containing the commonly used chemical oxybenzone out of concern that it can disrupt hormones, cause allergic reactions and damage cells. “It’s one of the most absorbed sunscreen blockers, which wouldn’t necessarily be a concern but it has high toxicity issues,’’ said EWG senior analyst Sonya Lunder. But the American Academy of Dermatology recommends oxybenzone because it ensures “broad-spectrum’’ coverage, which means it filters out both UVA and UVB light. Pick your side.

Be wary of “seals of approval.’’ The AAD has been criticized by some of its members for its commercial endorsement of sunscreens. Many AAD officers have ties to companies that manufacture sunscreens. One product with the AAD seal, Johnson & Johnson’s Aveeno Sunblock Lotion with SPF 55, contains oxybenzone; it scored a “moderate’’ risk in the EWG rankings.