Picking the most powerful sun protection

"There are only four approved ingredients known to block UVA rays," says Sean Gray, a senior analyst with the EWG. These include: zinc oxide, titanium dioxide, avobenzone, and mexoryl. The bad news is avobenzone and mexoryl are highly unstable and break down quickly in sunlight.

"Many companies use avobenzone as a UVA blocker," says Gray. "And on it's own, it just doesn't cut it." 

Some companies, including Neutrogena, La Roche-Posay, Vichy and Ombrelle, add ingredients to increase the photostability of avobenzone.

"At the time, however, there's no third-party verification," says Gray. "So if you're relying on avobenzone to block UVA, it's a trust issue. "

To be safe, parents should look for a sunscreen with at least a seven percent concentration of zinc oxide or titanium dioxide. These are stable ingredients that will protect against UVA rays for at least two hours.

• < UVA versus UVB Rays - Why you need to know the difference
• 1
• 2
• 3
• 4
• 5
• Could your sunscreen do more harm than good? >