If you thought that sunscreen with a sun protection factor of 30 was high enough, check out a product from Hawaiian Tropic with an SPF of 70. Yes, 70.
The company claims the sunscreen, which has a tropical fragrance, has the “highest SPF in Canada.”
Although those claims are impressive, dermatologists warn against thinking that higher numbers mean better protection.
“It may be higher in SPF,” says Dr. Jason Rivers, former director of the sun-awareness program for the Canadian Dermatological Association, “but you don’t derive much benefit from it in real life.”
That’s because the higher the number, the less difference it will make.
The calculation roughly follows an inverse-ratio pattern, Rivers explains. An SPF of 2, for instance, will be 50 per cent effective against the sun’s harmful ultraviolet-B rays. An SPF of 4 will block 75 per cent. A rating of 15 will block 94 per cent, and one of 30, 97 per cent.
Beyond that, there’s not much room left.
In fact, beach-blessed Australia doesn’t allow claims beyond the label “30+.”
Doctors also warn that SPF indicates nothing about blocking the other harmful radiation, UVA, which Quebec City skin-cancer specialist Dr. Joel Claveau says Health Canada has not regulated, despite being urged to do so.
“There is no way to compare sunscreens based on UVA factors,” Claveau says.
He notes that consumers must look for chemicals in sunscreen, such as Parsol 1789, Mexoryl SX, Mexoryl XL or Tinosorb, which absorb UVA.
Though ultra-high SPF ratings may be overkill for most people, Rivers points out that for a few, they could be essential. For those with immune-system disorders, such as lupus and polymorphic light eruption, they would be useful in reducing sensitivity to skin cancers, he says.