'Tis the delicious season of sea, salt and sunshine, but it comes with a harsh bite.
For we are a sunburnt country, in more ways than one.
Every weekend, about 330,000 (or close to the entire population of Canberra) Australian adults end up with seared skin, the damaged cells reddened in distress.
Given that between 95 and 99 per cent of skin cancers are caused by exposure to the sun, this is not exactly desirable.
The logical answer seems to be to slip, slop, slap and slide (the "cool" new, updated catchphrase to include wearing sunglasses) or just to stay out of the sun.
The sun-smart message makes sense, but, while sunscreen protects us, there are questions about the problems it may expose us to.
VITAMIN D DEFICIENCY
Vitamin D deficiency is one problem.
Up to 58 per cent of Australians suffer from a deficit of the "sunshine vitamin", which among other things helps us absorb other vitamins and minerals, keeps our bones strong and our heads and hearts happy.
In response, a new product SolarD, was launched in Australia last week.
It claims to be a "world first", offering protection from ultraviolet A (UVA, which ages) and all ultraviolet B (UVB, which burns) except for the tiny part of the spectrum that allows the body to produce vitamin D.
SolarD was designed "to permit a certain amount of the very efficient sun rays to reach the skin to produce vitamin D while protecting the skin from the other damaging ultraviolet rays", explains Dr Michael Hollick, a specialist in vitamin D from Boston University, who has conducted research on the new sunscreen.
Its promise is big, but the Cancer Council is hesitant about the product.
"Any lowering of the UVB filter would have to be minimal to ensure the sunscreen still met SPF [sun protection factor] requirements, so any vitamin D benefit would also be minimal," says Craig Sinclair, chairman of the Public Health Committee of the Cancer Council.
"Furthermore, given we know that sunscreens allow vitamin D production, further research would be needed to prove whether this sunscreen offers any substantial benefit over standard sunscreens already on the market."
Regardless, vitamin D production is not the only potential issue with sunscreen.
CHEMICAL SUNSCREENS
There are two types of sunscreen we can use: chemical or physical.
"The chemical or organic sunscreens absorb UV light while physical sunscreens mainly reflect it," explains Emma Hobson from the International Dermal Institute.
"Frequently, both types are used in combination for optimum effect in a product.
"You could think of organic filters as sponges, mopping up the UV radiation, and inorganic filters as mirrors, bouncing UV straight back off the skin."
Increasingly, questions are being asked about the ingredients some chemical sunscreens contain and their potential impact.
Oxybenzone, an ingredient common to chemical sunscreens, for instance, has been pegged as problematic by the not-for-profit Environmental Working Group (EWG).
The group, which has its own research arm, has given oxybenzone a hazard score of 8 out of 10 and listed it as a potential endocrine disrupter.
"It acts like oestrogen," says Ginni Mansberg, a GP who has no affiliation with the organisation.
"It sits on the oestrogen receptors and activates them ... but we don't know what that does."
Another ingredient, octinoxate (octylmethoxycinnamate), has a hazard rating of 6 out of 10 for similar reasons.
Both ingredients have moderate to high rates of skin allergy, EWG says.
Add to this that the chemicals in nanoparticle sunscreens have been found to affect marine life and to accumulate in the sea, according to a new study, sunscreen does not paint such a sunny picture.
While the chemicals that cause concern are allowed in Australia, they are on the FDA watch list, Dr Mansberg says, adding that we take a innocent-until-proven-guilty approach to banning ingredients or products.
"There's a paucity of data around these things," Dr Mansberg says, pointing out that testing is expensive and it is hard to isolate one ingredient as the issue.
According to the Australasian College of Dermatologists' position statement: "There is currently no scientific evidence demonstrating long-term side effects including any hormonal effects, following regular use of sunscreen."
PHYSICAL SUNSCREENS
The alternative is physical sunscreen, which contains zinc oxide or titanium oxide.
"They seem to be pretty safe," Dr Mansberg says.
Physical sunscreens have the added advantage of being active immediately (chemical sunscreens take 20 minutes to work) and offer a broader spectrum of protection.
"But the problem is they can feel disgusting."
Technology is improving so that physical sunscreens have a more lightweight feel, but there's still a way to go.
WHAT IS THE ANSWER?
In the meantime, what are we to do?
Obviously we can check the ingredients list and try to steer clear of the ones with a big question mark.
Dr Mansberg advises staying out of the sun while it's at its most intense between 10am and 2pm.
As for which sunscreen to use, she uses a physical sunscreen but does not avoid chemical ones nor advise others to either.
Like many potentially harmful products, it seems to be an issue of exposure, Dr Mansberg says, and sunscreen should not be a hazard, based on the quantities we use.
"The thing with these sunscreens is that they're probably OK, but it's a brave doctor who will put their head on the block and say they're definitely OK," she says.
The Cancer Council and Australasian College of Dermatologists reiterate their position that the chemicals used in sunscreen in Australia have been tested and approved by the Therapeutic Goods Administration.
However, they say that sunscreen should not be used as "the first or only line of defence" against ultraviolet radiation.
Rather, they say, it "should always be used in conjunction with other sun protection measures."
