Sunscreens

What difference does the SPF make?

"SPF" stands for "sun protection factor". It's a measure of protection against mainly UVB rays, the ones that cause sunburn. The higher the SPF number, the greater the protection - up to 50+.

Above SPF 50+ the additional protection is very small. In fact, high SPF values are a problem. Studies have shown that people use them to stay out longer in the sun, using sunburn as a warning to take cover. During this time you can receive large doses of UVA radiation.

What do the SPF numbers mean?

An SPF15 sunscreen that's properly applied is meant to give you 15 times the protection you'd get with unprotected skin. So if you were outside in the sort of sun that burns unprotected skin in 10 minutes, then SPF15 would give you 150 minutes of protection. For SPF30 sunscreen, that time would extend out to 300 minutes and for SPF50 it would be 500 minutes.

That’s the theory. These times will vary from person to person because of skin type, activities (such as heavy exercise or swimming) and how well the sunscreen is applied. No matter how high the SPF, any sunscreen should be reapplied regularly – every two hours you’re in the sun.

No sunscreen blocks 100 percent of UV rays: SPF15 blocks 93 percent of UVB, SPF30 blocks 97 percent, and SPF50 blocks 98 percent.

What does broad spectrum mean?

Broad spectrum sunscreens protect against UVA and UVB radiation. Both contribute to premature skin ageing, damage to the immune system and skin cancer.

UVA radiation penetrates deep into the skin layer; it's dangerous because there's no immediate warning sign (such as the sunburn caused by UVB rays).

Will the sunscreen protect me all day?

No - sunscreen can be sweated, washed or rubbed off, the chemicals may break down over time, and people simply don't apply enough (see "Sun safety tips" above). You should reapply sunscreen every 2 hours.

Does having a tan mean you don't need as much sunscreen?

No. A tan is a sign that skin damage has already started. Any further UV radiation will only add to the damage, resulting in wrinkled leathery skin and possibly skin cancer later in life.

Do I need a special sunscreen for my child?

Proper protection from the sun is more important during childhood than at any other time in life. Childhood and teenage sunburn is a high-risk factor for developing melanoma.

Sunscreens that are specially formulated for children have a mild base designed especially for their sensitive skin. But there's no reason why children shouldn't use the family sunscreen, provided it doesn't irritate their skin. Test a small amount on the inside of their forearm first.

Babies younger than six months shouldn’t have sunscreen applied, unless they can’t be protected by shade and clothing. Infants have a thin, less developed skin barrier and are more likely to be irritated by ingredients.

The New Zealand Dermatological Society recommends physical sunscreens, such as zinc oxide or titanium dioxide, for children. This is because they don’t irritate, they provide excellent broad-spectrum protection and they aren’t absorbed into the body.

Keep babies and toddlers out of the sun as much as possible. The best protection for them is staying in the shade and using cover-up clothing - as it is for everybody.

What about irritation?

Certain ingredients in sunscreens can irritate some people. This may be due to sensitive skin or a reaction to one of the ingredients (a chemical, preservative or fragrance).

The active ingredients in sunscreens must be listed on the label. However, unlike other cosmetics, sunscreens are exempt from having to list all ingredients if they comply with the Australian requirements.

You can check the active ingredients and preservatives of our tested sunscreen here.

What's in them?

Sunscreen active ingredients can be divided into two groups – physical blockers and chemical absorbers.

Physical blockers (zinc oxide and titanium dioxide) work by reflecting or scattering UV radiation and are effective at protecting against both UVA and UVB radiation. A downside is they leave white marks on the skin, although some products use nanoparticles – tiny molecules with one or more dimension less than 100 nanometres (nm) – which makes the sunscreen transparent.

There has been debate about the safety of nanoparticles and whether they can penetrate the outer layer of skin (which has been shown in lab studies) and damage living cells.

The Australian Therapeutic Goods Administration (TGA) states nanoparticles in sunscreen don’t pose a threat to your health. In 2017, it published a review concluding the majority of studies found nanoparticles didn’t penetrate “or minimally penetrated” the skin, suggesting “systemic absorption, hence toxicity, is highly unlikely”. The TGA states new research supports this conclusion.

The European Commission concluded available evidence suggests zinc oxide and titanium dioxide nanoparticles can be considered safe for use on the skin as sunscreens up to a concentration of 25 percent. This does not apply to sprayable products, which might be inhaled.

According to the New Zealand Dermatological Society (NZDSI) physical sunscreens have an excellent safety profile and have not been found to be systematically absorbed even when used as nanoparticles on normal skin. However, it cautions against physical aerosol sunscreens because of the respiratory risk from inhalation.

With cosmetic products, which include sunscreens, nanoparticle ingredients are required to be labelled. The word “nano” must appear in brackets after the ingredient. However, if a sunscreen complies with Australian regulations, this isn’t required and products don’t need to declare the ingredients’ particle size.

Chemical absorbers (such as octinoxate or oxybenzone) work by absorbing UV radiation and can be further differentiated by the type of radiation they absorb – UVA or UVB. These sunscreens often have a combination of ingredients to protect against UVA and UVB.

Some people choose to avoid sunscreens with chemical absorbers because of potential health risks. In 2019, a study by US Food and Drug Administration (FDA) researchers found four chemicals (avobenzone, oxybenzone, octocrylene and ecamsule) may be absorbed through the skin at levels higher than previously believed.

In January 2020, a follow-up study by the same researchers on six sunscreen ingredients (avobenzone, oxybenzone, octocrylene, homosalate, octisalate and octinoxate) supported these findings.

The FDA has not said these chemicals are unsafe, but has asked the industry to provide additional information on 12 sunscreen ingredients to validate their safety and effectiveness.

The European Commission is also investigating whether some sunscreen chemicals have endocrine-disrupting properties. It has asked for scientific data on 14 chemicals and published scientific opinions on four to date.

It concluded octocrylene is safe as a UV filter up to 10 percent on its own or in combination with other UV filters (however shouldn’t exceed 9 percent in a propellant spray). However, the commission has raised concerns about certain levels of homosalate and oxybenzone (also called benzophenone-3), although notes this evidence is “inconclusive", and concerns about 4-MBC (4-methylbenzylidene camphor).

Australia’s Therapeutic Goods Administration told us it’s currently reviewing the scientific literature to determine the safety of a number of active ingredients used in sunscreens marketed in Australia.

The NZDSI website states some chemical sunscreens have been found to be systematically absorbed after regular use. The society said although there are no known harms, further study is required to confirm this. It also states studies in humans have been reassuring with no evidence for endocrine effects in humans.

President of the society Dr Denesh Patel said, UV radiation is the major contributor to skin ageing and cancers. “Sunscreens are an important part of sun protection. They can be used safely and their benefits far outweigh the small chance of side effects.” By covering up more, less sunscreen is required, further reducing any risk of chemical absorption.”

However, the society cautions against applying sunscreen to inflamed or broken skin through which sunscreens can be more easily absorbed. It recommends other sun protection methods, such as wearing sun-protective clothing (UPF rated) on these areas.

Are nanoparticles safe?

There is debate about the safety of nanoparticles and whether they can penetrate the outer layer of skin (which has been shown in lab studies) and damage living cells.

In 2017, the Australian Therapeutic Goods Administration concluded the majority of studies found nanoparticles didn’t penetrate “or minimally penetrated” the skin, suggesting “systemic absorption, hence toxicity, is highly unlikely”.

The European Commission (EC) concluded available evidence suggests zinc oxide and titanium dioxide nanoparticles can be considered safe for use on the skin as sunscreens up to a concentration of 25 percent. This does not apply to sprayable products, which might be inhaled.

With cosmetic products, which include sunscreens, nanoparticle ingredients are required to be labelled. The word “nano” must appear in brackets after the ingredient. However, if a sunscreen complies with Australian regulations, this isn’t required and products don’t need to declare the ingredients’ particle size.

What's the environmental impact?

Some ingredients – in particular oxybenzone and octinoxate (also called octyl methoxycinnamate) – are emerging as environmental concerns, especially in beach regions where they get washed off.

Due to the evidence showing these ingredients adversely affect marine life, the NZDSI recommends using sunscreens without them. Sunscreens containing oxybenzone and octinoxate are banned in Hawaii, except on prescription. The Republic of Palau has also banned these ingredients, as well as additional sunscreen chemicals.

To choose sunscreens without these chemicals, check the packaging – all active ingredients in sunscreens must be listed.

To minimise the amount of sunscreen washing off in our beaches, cover up with UV-protective clothing. Also skip the spray. Aerosols cause sunscreen particles to fall to the sand where it can be washed into the ocean.

Are aerosols effective?

We often get asked why we don’t test aerosol sunscreens and whether they provide effective sun protection.

Aerosols are quick and easy to apply. But most people don’t apply enough – giving a light spray instead of the recommended nine teaspoons for an average-sized adult. Aerosols are also expensive. The Australian consumer organisation Choice estimates only about 40 to 60 percent of an aerosol can is sunscreen – the rest are propellants. Also these propellants are flammable, which means there’s also a potential safety issue.

They may seem an easier option to use on kids but there’s the risk of accidentally inhaling the sunscreen – so it should be sprayed on your hands first and then applied. This also helps ensure you get an even layer of coverage and don’t miss any areas.