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. 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.

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 the sunscreens in our database.

What’s in sunscreen?

Sunscreen active ingredients can be divided into two groups – mineral (sometimes called physical) and chemical ingredients.

Mineral ingredients (zinc oxide and titanium dioxide) were previously thought to reflect or scatter UV radiation. Studies have since shown that, like chemical ingredients, they protect by primarily absorbing UV radiation. They are effective at protecting against both UVA and UVB radiation. A downside is they leave white marks on the skin. However, 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) has stated that nanoparticles in sunscreen don’t pose a threat to your health. In 2017, the TGA published a review concluding the majority of studies found that nanoparticles didn’t penetrate “or minimally penetrated” the skin, suggesting “systemic absorption, hence toxicity, is highly unlikely”. It has also stated that 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 NZDSI, mineral sunscreens have an excellent safety profile. However, it cautions against using mineral aerosol sunscreens because of the respiratory risk from inhalation.

With cosmetic products, which include sunscreens, nanoparticle ingredients must be labelled. The word “nano” must appear in brackets after any applicable 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 ingredients (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. Sunscreens often include a combination of chemical 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 researchers from the United States Food and Drug Administration (FDA) found that 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% on its own or in combination with other UV filters (however, it shouldn’t exceed 9% in a propellant spray), and homosalate is safe as a UV filter up to 7.34%. However, the commission also raised concerns about certain levels of oxybenzone (also called benzophenone-3), although it noted this evidence is “inconclusive”, and about 4-MBC (4-methylbenzylidene camphor).

The commission is currently consulting on a draft opinion on the UV filter ethylhexyl methoxycinnamate.

The TGA told Consumer NZ it’s currently reviewing the scientific literature to determine the safety of a number of active ingredients used in sunscreens marketed in Australia.

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

A spokesperson for NZDSI 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, NZDSI cautions against applying sunscreen to inflamed or broken skin, which can absorb the sunscreen more easily. 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?

While most sunscreen ingredients have been detected in our oceans, oxybenzone and octinoxate (also called octyl methoxycinnamate) – are the ones raising the most environmental concerns, especially in beach regions where they get washed off.

Sunscreens containing oxybenzone and octinoxate are banned in Hawaii, except when being used in prescription-only products. Other regions such as the US Virgin Islands and Palau have similar bans. Thailand has announced a ban of certain ingredients being used in its national parks.

Some sunscreens promote their environmental credentials, the most common being that they are ‘reef-safe’ or ocean-friendly. This tends to mean that oxybenzone and octinoxate aren’t used.

However, terms such as “reef-safe” and “ocean-friendly” aren't regulated, so there's no consensus on what they mean or which products they can be applied to.

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 whether aerosol sunscreens provide effective protection.

Aerosols are quick and easy to apply. But most people don’t apply enough – giving a light spray instead of the recommended 7-9 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.

Does sunscreen expire?

Don’t use sunscreens past their expiry date. Ingredients may separate over time, affecting the distribution of active ingredients and protection from UV radiation. An expired sunscreen may still look, feel or smell the way it did when new, so always check the expiry date and throw out anything that has been around longer than three years. If in doubt, chuck it out!

Some products state an expiry date, others include a production date with an expiry symbol. You may need a magnifying glass to read the details though as some are well hidden and written in tiny font!

If you can’t find a date, sunscreen should last two to three years if stored properly – although if you are using the recommended amounts, you should run out by then. Regardless of the expiry date, store sunscreens out of direct sunlight and other hot places, such as your car’s glovebox.

Does using sunscreen lead to vitamin D deficiency?

Vitamin D is important. It helps us build and maintain healthy bones and teeth and improves our immunity. Our bodies produce vitamin D when we get sun on our skin. How much sun exposure you need depends on different factors, such as your skin colour, where you live, how much skin is exposed, the season and time of day and how much vitamin D you get from food. Good food sources include oily fish, eggs and fortified dairy products, but it’s difficult to get enough vitamin D solely from food.

The NZDSI says that usual recreational use of sunscreens doesn’t lead to vitamin D inadequacy. If you have fair skin, it takes less than 3 minutes of midday summer sun to make enough vitamin D if you’re wearing shorts and a T-shirt (for people with darker skin it takes longer). Being physically active outdoors helps you make more vitamin D than resting in the sun.

Sunscreen is a filter, not a block. This means sunscreen-protected skin still produces some vitamin D, but the process takes longer. The NZDSI recommends if you may be outside for more than 3 minutes, apply sunscreen to all exposed skin. It’s important you don’t get sunburnt while getting your vitamin D hit.

If you think you’re not getting enough vitamin D, talk to your doctor. Some people with a vitamin D deficiency may need to take a supplement.