Expert reveals the biggest mistakes we're all making when it comes to sunblock

We’ve all grown up knowing the three simple rules of staying sun safe: Slip, slop and slap.

But it turns out there is a handful of things we’re getting wrong when it comes to putting on sunscreen and it’s leaving us at risk of being badly burnt or developing skin cancer.

Australian dermatologist Dr Natasha Cook told Daily Mail Australia what some of the biggest mistakes are and how we can better protect ourselves from the scorching sun this summer.

The most common errors we’re making is simply not using enough sunblock when we apply it.

According to studies people often use less than half of the sunscreen they’re supposed to, which means they don’t get the full effect of the SPF protection, Dr Cook explains.

"There is an exponential dose-protection level relation, which means if you under-apply by half, you are effectively getting only a quarter of the correct SPF protection," Dr Cook says.

"If it's a teaspoon per face and one for each limb - let alone your back - a 100mL bottle will only last you a couple of applications."

Dr Cook also suggested that spray-on sunscreen could be worse for us than using cream.
"Aerosols do not give enough coverage and encourage people to significantly under-apply," Dr Cook adds.

"They also end up with skip-areas, leading to streaky gaps that end up getting burnt."

"So people like them because you feel like you are wearing nothing. The reality is you probably are."

Another big issue is thinking that one application of sunscreen will last a full day, even if we’ve been in the water.

Although a lot of sunscreens are now water-resistant, they fully waterproof and so "most people don’t apply frequently enough."

She says a good "rule to minimise under-applying" is to cover yourself every two hours with "a teaspoon for the face and a teaspoon per limb."

Dr Cook says it’s also important that being tanned or having a spray tan does "not give you any protection whatsoever" and that you still need to have sunscreen on your body even if you’re wearing a t-shirt.

"Sun goes through white fabric," she says, "A fine, white t-shirt probably only has an SPF equivalent of four."

Finally, Dr Cook’s last part of advice was to wait before we jump in the sun as sunscreen takes 20 minutes to take effect and yet "it only takes about six minutes to burn in the peak of the day".

So make sure you put on sunscreen thoroughly before you go outside or hit the beach and avoid those nasty burns this summer.