Wise up for the warmer weather with informed sun care choices.

We're sunscreen slackers, but not for want of warning. We've all heard the sun protection messages, it's just that for plenty of us they don't seem to be sinking in. Turns out we use one bottle of sunscreen per four New Zealanders each year, when at peak summer times we should apparently be going through a bottle each every few weeks.

Maybe we're confused about what bottle to actually pick up, let alone how much to apply: SPF what? Chemical or mineral, natural or not? The latest products won't make the choice any easier.

For the first time an SPF100 has arrived on the market. Advances in mineral sunscreens are raising issues around the use of uncleared nano-technology and there's possible confusion in determining if you are buying a purpose-designed sunscreen or a cosmetic product with a sunscreen added. (In Australia such products are deemed to be "secondary" sunscreens so the likes of moisturisers may not claim therapeutic benefits or a sun protection factor over 15).

Check that whatever you use filters both UVA and UVB rays, offering broad spectrum coverage.

A new Australia-New Zealand product standard is looming which is likely to toughen broad spectrum provisions and lift the current cap on sunscreens from SPF30 to SPF50. The existing standard dates from 1998 and is mandatory in Australia yet voluntary in New Zealand. Because New Zealand accepts European and American standards, as well as the Australasian one, higher SPFs can legally be sold here and differing claims made about their applications.

One thing is clear though and that is the need for commonsense in our approach to sun exposure. Sun awareness has improved over recent decades, but skin cancer rates are not yet falling. We're more likely to fry here than elsewhere in the world thanks to our outdoor lifestyles, our clean, clear air and the hole in the ozone.

Dermatologists despair that recent publicity about the relatively rare incidence of vitamin D deficiency being caused by lack of sun exposure will prove another barrier to the public health message sinking in.

"A bit of time outside will do for vitamin D, or you can take it orally," says Remuera dermatologist Dr Elizabeth Baird who deals daily with the aftermath of those who spend too much unprotected time outdoors.

Her advice is that familiar message we ignore at our peril. Wear a hat, seek out shade, avoid the sun at peak times, keep young children covered and, of course, use a sunscreen and use it thoroughly, applying half an hour before exposure.

The generally accepted prescription for full body coverage is a golf-ball sized amount, or a shot glass full. The face requires a couple of pea-sized or a teaspoon-full application. If this sounds excessive, bear in mind the risk of prolonged sun exposure isn't just about being burned, it's also about long-term skin damage, everything from pigmentation to potentially fatal skin cancers appearing years later.

Chemical vs mineral

Sunscreens fall into two main types, the chemical (or organic synthetic substances) and the physical (sometimes called mineral or inorganic natural filters). Chemicals absorb UV light and physical ingredients such as zinc oxide and titanium dioxide block or diffuse it.

Many sunscreens combine both types for maximum effectiveness, but chemical sunscreens dominate sales and are generally cheaper to produce.

Both chemical and physical blocks can cause sensitivities, but sensitive skin reactions are more common to chemical blocks, with some potentially irritating compounds such as PABA often now advertised as not being present. Titanium dioxide can also irritate. Reactions vary widely from product to product depending on individual ingredients. If you have sensitivities try using baby block, or switch brands.

Chemicals generally bond well with the skin, mineral-based physical blocks can sit obviously on top of it, though the new micro-ionised and nanotechnology zincs are not visible. (Micro-ionised zinc is formed by an engineered cluster of tiny particles, a bit like a bunch of grapes. If the particles were separate they would be considered nano-particles, but as a cluster group they are not.)

Most manufacturers internationally are holding off introducing nano-tech to market because of fears of a consumer backlash amid concerns that not enough hard scientific data exists for how the body will deal with readily absorbable tiny substances. It offers exciting ingredient delivery potential, however, and is the subject of much exploratory research.

After Herald inquiries mid-year, cosmetic importers and manufacturers were reminded by their industry body of obligations to notify government authorities of any nano presence in products.

Take cover

If you've just dragged something crusty looking from the cupboard, best check the expiry date. Sunscreens sitting on the shop shelf usually last two to three years from manufacture, but once opened you are best to use them within a few months to safeguard against degradation, which leaving them lying about can cause.

If the only sunscreen you have at hand is old, remember it is better than wearing none, and whatever factor you use, reapply it every few hours. Keep it cool at the beach by popping it in a chilly bin. Here are some of the newest sunscreens to hit New Zealand shelves but there are also plenty of other existing products out there, with good examples across the price ranges. We'll look later at more multi-purpose skincare containing sunscreens.

1. Aveeno Continuous Protection Face Sunblock Lotion SPF70 $24.95
Soy extracts and vitamins are included in the mix to offer skin a boost while protecting it with this oil-free, waterproof sunscreen. Suitable for sensitive skins and with a photo-barrier to make its UV filter last longer. Aveeno's new fragrance-free Baby Block SPF55 also contains soothing oatmeal to help retain moisture to the skin. (Selected supermarkets, pharmacies and Farmers, ph 0800 446 147.)

2. Shady Day Daily Sun Protection Wipes SPF30 $12.99
Convenient sachet of saturated wipes with a pleasant citrus smell. Hard to tell how much you're applying, but each wipe is meant to work once for all over. This American award winner is paraben and PABA free. (From usual sunscreen outlets.)

3. Invisible Zinc Face + Body Sunscreen SPF30 $39
By using zinc oxide milled down to an average particle size of one micron, this is invisible but still much larger than nano particles. It adds to the Australian range launched here a year or so ago and fronted by sun-worshipping Elle Macpherson. One to seek out for its pleasant feel. There's also a clever Junior Clip On ($24.95) that sports fans could attach to their gear bags. (From selected health stores and pharmacies.)

4. Nivea Sun Caring Sun Spray SPF50 $22.59
Nivea's top-selling SPF30 spray (and lotion) now comes in an SPF50 formula that goes on as easily and feels as pleasant on the skin. Upgrade to give the family a little more protection. (Supermarkets and pharmacies, stockists ph 0800 800 081.)

5. Neutrogena Sensitive Skin PureScreen Sunblock Lotion SPF60 $22.95 (disc)
Mineral filters and a fragrance-free formula make this one of the most highly rated options around suitable for sensitive skins, plus its fragrance, oil and dye free. Contains both titanium oxide and zinc oxide. (From selected supermarkets, pharmacies and Farmers.)

6. Banana Boat Sport Dry Touch SPF30 $14.65
Big-selling budget range from Australia just launched here includes three sport products, plus every day, baby and kids' choices and a bargain aloe lip balm. ($2.99). The lotion dries quickly leaving a good non-greasy finish. Smells a bit chemical for my taste, but the easy-grip bottle sure won't blend into the sand. (Selected supermarkets, pharmacies and Farmers, ph 0800 446 147.)

7. L'Oreal UV Perfect Longlasting UVA/UVB protector SPF50 $15.29
The best thing is the handy little size, but this hybrid product which promises to work against pigmentation and ageing, is too betwixt and between to satisfy me. Comes in two versions: Transparent and Even Complexion, with the latter offering a little tinted coverage and a natural look and feel.

8. Antipodes Immortal Performance Plus Daily Moisturiser with SPF15 $52
Antipodes' sun filter uses zinc oxide dispersed in a coconut oil derivative and raspberry oil as its main screening agents to meet the Australia-New Zealand SPF15 standard. Kiwifruit and grape extract are part of the moisturiser's botanical power pack. antipodesnature.com

9. Trilogy Age Proof Daily Defence Moisturiser with SPF15 $54.90
Trilogy uses its foundation ingredient rosehip oil, with other plant's oils for skin conditioning alongside hyaluronic acid to lock in moisture in this plant-based skin conditioner which uses a synthetic filter for its sun protection. Uses inorganic and organic sun filters, which are photo-stable and broad spectrum. trilogyproducts.com
10. Evolu Moisturising Day Cream SPF15 $47
Evolu uses the synthetic avobenzone complex in its SPF15 moisturiser and hand cream. Kiwifruit seed oil, camomile and more provide botanical benefits in the facial cream. evolu.com
Expert insight
* The sun's main effects on skin - other than burning and tanning it - are wrinkling, photo-ageing and skin cancers. These issues affect people of all ethnicities.

* Skin is classified from Type 1 (always burns) to Type 6 (never burns), with Type 2-3 (burns easily or burns moderately) common to Caucasian New Zealanders. The average New Zealand woman shows more signs of skin damage than women of a similar age in Europe.

* UVA rays penetrate deep into the dermis, causing pigmentation, signs of ageing and cancers. UVB rays cause tanning and surface burning, with this typically showing up two to six hours after exposure. Sunburn's maximum effect is felt within 24-36 hours and it can last three to six days.

* New Zealand skin cancer rates are high, with nearly 400 deaths a year, two-thirds from melanoma. Skin cancers are under-reported, but there are around 67,000 cases listed annually, compared with 16,000 other cancers.

Source: Dr Elizabeth Baird, Remuera dermatologist.

* New Zealand's clear skies have up to 50 per cent more UV light than similar northern places. Coupled with the closeness to Antarctica and the ozone hole, (caused by waste gases), this makes New Zealanders and Australians particularly susceptible to skin damage. While ozone depletion is stabilising, it is unlikely to reverse until around 2060, and only slightly.

* The higher the sun is in the sky, the more UV rays hit us. UV is also high with clear skies and at higher altitudes, where more of the burning UVB is present than at ground level, where most of the rays are of the insidious ageing UVA kind.

* Clouds don't necessary shelter us, dense clouds do diffuse light, but white clouds cause reflectivity, helping UV reach the ground. Snow, water and white sand also reflect UV rays back up at us.

Source: Dr Neil Mitchell, senior lecturer environmental science at the University of Auckland.

* The first sunscreen was developed as "glacier cream" in Switzerland in the 1960s by Austrian chemist Professor Greiter who also worked out the SPF measurement we still use to rate UVB filtering. (Sunscreens now usually filter UVA rays also). Glacier cream was produced by Piz Buin, now owned by Johnson & Johnson.

* The light spectrum is 68 per cent UV light, but there are also other types, the effects of which are less understood, but now being researched. Up to 50 per cent of free-radical production is from visible and infrared light sources, the rest from UV. (Free-radical action is considered a key cause of premature ageing, or photo-ageing and the use of topical antioxidants in a bid to counter this is widespread in the beauty industry).

* Sun damage includes skin darkening (pigmentation, age spots, and so on), dermal matrix degradation (to collagen and elastin), a leathery look to skin, cataracts and possible effects on DNA.

Source: Dr Curtis Cole, senior director of technology at Johnson & Johnson.

NB: Drs Baird and Mitchell spoke as independent authorities at a recent Johnson & Johnson product launch.