KEY POINTS:
Slip, slop, slap and wrap. It's a simple enough method to stay safe in the sun.
But according to sunscreen specialist Rick Woodin, it may not be enough.
"All sunscreens appear alike on the surface but they're not. They're not providing high, broad and definitely not photostable protection,"
said the Los Angeles-based scientist.
"Photostable means [the product] does not break down in the sun. Many products sold here today begin to break down in just 30 to 60 minutes."
In short, many sunscreens are not providing the level of protection they claim to.
Combined with misapplication - something Mr Woodin says nearly everyone is guilty of - most SPF30 sunscreens become little more effective than SPF5 over time.
The scientist, who has spent 25 years working in the sunscreen industry, said SPF30+ did not offer significant protection and people should aim to use SPF50+ or higher.
Cancer Society spokesperson Catherine Chittenden agreed that most people did not apply sunscreen as directed but said SPF30 should provide substantial sun protection when applied properly.
She said when testing sunscreens for their SPF factor, test subjects are given 35ml for a full body application.
"Now that's a lot of sunscreen. People don't put it on as thickly as that and that's why they're not getting the full SPF value," she said.
During consumption testing in the United States, Woodin and his researchers found people used less than half the prescribed amount of sunscreen and did not apply it evenly.
"We're not using enough and we're not putting it on right," he said.
Mr Woodin said people should be using around 1 fl oz [29ml] of sunscreen for a full body application, which is around a palm full of cream.
Mr Woodin, who is employed by Neutrogena and developed their new Helioplex complex, said many sunscreen manufacturers were using old technology to keep costs down for both themselves and consumers.
"There's a cost associated with research. You get what you pay for."
Ms Chittenden said she could not comment on Mr Woodin's findings as she had not seen his research first-hand, however, she said there was no regulatory body in New Zealand, which was a pressing issue.
"That is the most important thing for New Zealand, to get sunscreen legislated. To give the public an assurance that it's been independently verified by somebody."
Top tips to stay safe in the sun:
*Read the instructions and apply the product properly. Aim to use a palm full of sunscreen for a full body application.
*Re-apply your sunscreen throughout the day.
*Don't just use sunscreen in recreational, high exposure environments. Incorporate it into your daily routine.