Sun safety 101: the 3 sunscreen ingredients to avoid and why

Sun safety is an essential part of daily life in Australia. And, while you might think you only need it when you go outside, you should be wearing sunscreen every day of the year.

Why? Well, because even if you're sitting at home or in an office all day, the sun can still get you through the glass. The sun's UV rays can even damage your skin on a cloudy day.

Australia has one of the highest rates of skin cancer in the world, and sunscreen is one of your best tools (as well as staying out of the sun entirely or wearing sun-protective clothing) to reduce your risk of skin cancer [1][2].

Sunscreen is also one of the best anti-ageing products you can find, so if you want to lessen the impact of sun damage, it's best to include facial sunscreen and body sunscreen as part of your daily skincare routine. If you use it from a young age, you'll be surprised how great you look into your 50s and beyond.

However, there are some ingredients you may want to avoid when it comes to sunscreen, so let's look at what to look for next time you're at the shops.

Is sunscreen safe?

Despite what you may have heard from an influencer online, sunscreen products are safe and effective at protecting your skin from the sun and UV radiation. Sunscreen reduces the effect of UV rays on the skin, which can help prevent the development of skin cancers such as melanoma.

When buying sunscreen, you should look for products with an SPF of at least 30+. SPF stands for Sun Protection Factor, indicating the amount of UVB radiation that can reach the skin with sunscreen compared to skin without sunscreen [3].

Simply put, if you were wearing SPF 50+ sunscreen, you could be in the sun for 50 times longer before burning than if you weren't wearing any at all. However, even if you apply sunscreen correctly, some UV will still penetrate the skin.

SPF is only a measurement of protection against UVB, so some sunscreens with the same SPF rating may offer different levels of protection against UVA rays. This is why it's important to wear sunscreen that is labelled 'broad-spectrum' as this protects from both UVA and UVB rays.

UVB rays are the main cause of sunburn, as it's more energetic, however, UVB rays cannot penetrate glass windows. On the other hand, UVA penetrates more deeply into the skin and cannot be blocked by window glass.

UVB and UVA radiation can contribute to precancerous and cancerous changes to the skin and ageing effects, including dryness, pigmentation and the loss of elasticity and sagging.

It's important to note that sunscreen is highly regulated by the Therapeutic Goods Administration (TGA) in Australia to ensure the safety of consumers.

Chemical sunscreens vs physical sunscreens: what's the difference?

When shopping for sunscreen, you'll find 2 different types: physical and chemical. The difference between these is mostly in how they block the sun's harmful rays.

Sunscreen works in 2 ways:

• Physical: Reflects or blocks UVA and UVB rays away from the skin
• Chemical: Absorbs UV energy and prevents it from getting into skin cells.

Physical sunscreens, which are also commonly known as mineral sunscreens, usually contain zinc oxide and titanium dioxide. This type of sunscreen will usually make the skin appear milky-white after application, however, thanks to advancements, this is getting better.

Mineral sunscreens are gentle enough for children and are also recommended for those with sensitive skin, skin allergies, oily skin or acne.

Chemical or absorbent sunscreens will contain a mixture of synthetic chemicals including cinnamates, dibenzoylmethane (salicylates) and benzophenones. These sunscreens will usually be invisible once applied to the skin.

There is a lot of debate about chemical sunscreen and the ingredients used as they may pose health risks. However, according to the Cancer Council, there is strong evidence that the most commonly used active ingredients in chemical sunscreen do not pose a health concern [4].

Whether or not you choose physical or chemical sunscreen, you should ensure you're looking for a product that has the following on the label:

• Broad spectrum protection (indicating both UVA and UVB protection)
• Fragrance-free
• Non-comedogenic (which means it won't clog your pores)
• Oil-free
• Paraben-free
• SPF of 30 or higher.

Sunscreen users should also make sure whatever product they are using hasn't expired.

How do the ingredients in chemical sunscreens work to protect?

The ingredients in chemical sunscreens work by absorbing UVA and UVB rays, which causes them to undergo a chemical reaction that prevents the UV rays from damaging the skin.

In simpler terms, it soaks up energy from the sun like a sponge, collects it, converts it, and releases it as non-dangerous radiation.

Some people prefer chemical sunscreens if they're swimming or playing sports outside and sweating a lot. However, chemical sunscreens can also cause skin irritations for people with sensitive skin types.

Due to the nature of the ingredients in chemical sunscreen, some may be absorbed into your bloodstream. This differs from physical sunscreen ingredients such as zinc oxide or titanium dioxide, which sit on the skin, act as a barrier, and do not penetrate the skin.

What are the sunscreen ingredients to avoid?

Many sunscreens may include some ingredients you may want to avoid, these include:

Oxybenzone (AKA BP-3)

This is a common UVA filter found in chemical sunscreens. It is also found in other products such as nail polish, lipsticks and lotions. Various studies have been performed on oxybenzone as it has shown endocrine-disrupting potential in animals [5].

There is some association that the ingredient may affect thyroid hormone levels in humans. However, the results are not conclusive at this stage. The same goes for the impact on fertility or female and male reproductive hormone levels.

There has been some increased concern with pregnant or breastfeeding women using sunscreens containing oxybenzone, as some of the chemicals can be found in breast milk and can also enter the amniotic fluid [6].

Developing embryos and foetuses are particularly vulnerable to endocrine-disrupting chemicals, as they may interfere with the hormones, neurotransmitters and growth factors important for normal development.

Some studies have yet to find any statistically significant association between prenatal exposure to oxybenzone and the child's development [7]. However, other studies have reported there is a potential risk [8].

A 2017 study by the Centre for Disease Control in the US revealed approximately 97% of people have oxybenzone present in their urine. It has also been found in various concentrations in waterways and fish worldwide.

Oxybenzone can also react with chlorine in pools and produce potentially harmful by-products that can concentrate in swimming pools and wastewater treatment plants.

This means it's possible we are eating fish contaminated with oxybenzone, and we may also wash the ingredient off our bodies and have it return to drinking water.

Oxybenzone may also have adverse reactions in coral and fish, ranging from reef bleaching to mortality.

Avobenzone

So far, avobenzone has inconclusive data on whether or not it is harmful to humans, however, it is an ingredient that can harm coral reefs.

Avobenzone has also been studied to find if it has any long-term effects on the endocrine system, including hormonal and reproductive disruption.

Aside from a small risk of skin sensitivity, avobenzone has shown to have no toxic effect or potential harm to human health [10]. However, researchers found that for avobenzone to impact oestrogen, the levels would need to be 100 times higher than they are when absorbed during regular sunscreen use [11].

Octinoxate

Octinoxate is another chemical that is found in numerous products that you may already use, such as lip balms, moisturisers, perfumes, hair sprays and more. It is also another chemical that scientists have found can damage marine ecosystems.

Similarly to oxybenzone and avobenzone, octinoxate is considered safe in specific concentrations. Having said this, it is classified by scientists as an endocrine-disrupting compound. However, the amount of octinoxate that can penetrate the skin barrier is limited, according to current research [12].

If the concentration is high enough, scientists have found octinoxate can pose a potential risk to animals, but it's unknown how this translates to humans.

Evidence suggests it may cause allergic dermatitis (itchy and inflamed skin), hormone disruptions (though this is currently unclear), and affect the nervous system [13][14][15].

However, this study involved extremely high doses of octinoxate — not the levels you'd usually find in the bloodstream.

It's important to note that just because these ingredients can be absorbed into the bloodstream doesn't necessarily mean they are harmful. More research needs to be conducted in this space.

However, you may choose to be on the safe side and use sunscreens with other ingredients for the environmental aspect as this is a clear negative to these ingredients.

What sunscreen is best for me?

Ask any dermatologist which sunscreen is the best for you, and their response will likely be, "the one you'll actually use."

It's incredibly important that you use sunscreen every day and while you're at it, you may want to avoid ingredients like oxybenzone, avobenzone and octinoxate due to their environmental impact.

The bottom line is: use whatever sunscreen you have in your home (as long as it's in date) and protect your precious skin.

Software’s Daily Sun Defence SPF50+ is fast absorbing, non-greasy and designed for every day wear. Formulated with UVA and UVB filters, which may reduce the risk of photoageing, sun spots and some skin cancers, the handy size makes it the perfect pocket or handbag companion so you’re never without.

Photo credit: Getty Images