I left for a recent sun-filled getaway determined to protect myself from tropical rays and armed with a cache of lotions, creams, gels and sprays promising advanced, all-day, broad-spectrum, water- and sweat-proof protection, with SPFs all the way up to 100+. I mean, the higher, the better, right?

I returned to Washington five days later with a face full of freckles and a burned scalp, wondering if sunscreen is everything it’s cracked up to be.

Not necessarily, say the folks at the Environmental Working Group, a nonprofit that assessed the safety and effectiveness of nearly 500 sunscreens last year. While these products can block harmful UV rays and prevent sunburn, which may lower the risk of skin cancer, “not all sunscreens are created equal, in terms of the level of protection they provide and also in terms of how safe are the actual ingredients,” says Olga Naidenko, a senior scientist at EWG.

She adds that since the Food and Drug Administration has yet to finalize sunscreen regulations (a process underway since 1978), manufacturers are not required to show that their products work or to substantiate claims about them. “Everybody is using whatever label words they want . . . and [making] absolutely crazy statements about efficacy which are not substantiated,” Naidenko says.

So all the hype about 100+ protection? The truth is that larger SPF numbers aren’t much better, according to Warwick Morison, a professor of dermatology at Johns Hopkins University School of Medicine. He notes that an SPF of 30 blocks around 98 percent of UVB rays, while an SPF of 100 guards against 99 percent of them. “It’s incremental,” he says, and the greater the SPF, the higher the chance of skin irritation.

More important, “higher SPF ratings may actually be giving people a false sense of security, where they think they ... can just put it on once and they’re protected all day long — which is not the case,” says Washington dermatologist Elizabeth Tanzi.

As for all those labels touting “broad-spectrum” protection, it’s important to note that SPF ratings in the United States are solely related to UVB rays, which cause sunburn, and do not address UVA rays, which can trigger deeper skin damage. UVA rays “are related to a number of known health effects, like immune suppression, connective tissue damage, premature aging and wrinkles, and also play an important role in the development of melanoma and potentially other skin cancers,” says David Andrews, also a senior scientist at EWG. He points out that two-thirds of the sunscreens the group evaluated last year would not meet European standards for broad-spectrum protection. As a result, he recommends reading product labels to find one of the gold-standard ingredients for UVA protection: avobenzone, zinc oxide or the slightly less effective titanium dioxide.

Even when you pick a good product, it’s essential to slather on at least a shot glass worth of cream for the average adult body. “The main problem with sunscreen is that people just don’t use enough of it,” says Morison, pointing to several studies showing that people tend to apply much less sunscreen than needed — even when they have specific usage instructions.

Make sure to cover the hairline, ears and tops of the feet, advises Tanzi, and reapply all over every two to three hours, even with supposedly waterproof products. “The notion of a sunscreen that lasts eight hours after a swim or sweating profusely — that’s just ridiculous,” she says.

Researchers at EWG have also been investigating the safety of sunscreens. Their findings identify two potentially hazardous chemical ingredients, says Andrews.

One is retinyl palmitate, a form of Vitamin A that’s in roughly 40 percent of all sunscreens — for its antioxidant, anti-aging properties and not because it protects against UV rays. But a recent FDA animal study found that it may hasten the development of skin tumors when it breaks down in the sun. The other is oxybenzone, a potential hormone disruptor that has also been associated with skin allergies.

Many doctors, including Morison and Tanzi, have no qualms about these ingredients, even though only limited research has been done on them. But Tanzi says she prefers sunscreens with blockers such as zinc and titanium, which sit on top of the skin and reflect UV rays, instead of chemical sunscreens, which absorb the rays. Manufacturers have improved the texture of reflective sunscreens by using tiny particles of these minerals to make clearer, lighter and more comfortable formulations. “You don’t have to have a white, pasty line across the nose anymore,” says Tanzi.

There has been some controversy over whether nanoparticles of zinc oxide and titanium dioxide get absorbed into the body. Still, Andrews says that from what is now known, “these products offer superior sun protection, and the benefits outweigh any potential health concerns, at this moment.” He adds that EWG will release an updated sunscreen report this summer that will rate products on health risks as well as UVB protection, UVA protection and other factors.

The bad news for parents whose lives have been eased by spray-on sunscreens? EWG doesn’t endorse these products, particularly those that are mineral-based and especially those intended for children. “We have generally been recommending the lotion-type sunscreen, due to concerns about inhalation,” says Andrews.

So what ‘s the take-away here? Remember that even the most effective sunscreens cannot block UV rays entirely. So stay out of the sun between 10 a.m. and 4 p.m., walk on the shady side of the street and wear sunglasses, a wide-brimmed hat and other protective clothing.

“Sunscreen is only one piece of the overall, good sun safety picture,” says Tanzi, a survivor of both melanoma and basal cell carcinoma.

“When I was a teen, I used to purposely try to get tan, and in college I went on spring break down to Florida and got fried,” she says, “and although I’ve been really great with my skin over the past decade . . . I’ve paid for my previous ‘sun sins.’ So now I’m really an advocate for early detection and skin cancer protection. We’ve all got to do what we can to keep ourselves safe from the sun.”