Chemical vs physical vs mineral sunscreen: What's the difference?

Living in Australia, you’ll know that protecting your skin against the harsh sun is essential.

Wearing a hat to shade your face, neck and head and applying sunscreen on your arms, hands, legs and feet is a habit we have to engage with every day.

With so many sunscreens available, it can be hard to figure out the best sunscreen. And if you have acne-prone skin, commonly experience reactions or have sensitive skin, it's even more challenging.

UVA and UVB radiation contribute to your skin ageing and make you more prone to sun spots, actinic keratoses and cancerous changes like melanoma, basal cell carcinoma and squamous cell carcinoma skin cancers.

By protecting your skin from the sun, you can reduce the risk of developing skin diseases — and also maintain a healthy and glowing complexion!

You can protect exposed skin by:

• Wearing sunglasses, a broad-brimmed hat and choosing tightly woven longer sleeved clothing.
• Staying in the shade, especially during the middle of a summer‚Äôs day
• Wearing rashie vests or wetsuits when swimming
• Applying either chemical or mineral sunscreens regularly.

So what type of sunscreen is best for you? Some have mineral actives, others can leave a white residue while some physical sunscreens sit on your skin. It can be tricky to find the perfect sunscreen that feels nice — especially when you have sensitive skin — and that protects you from UV rays.

With this in mind, we've lined up the main contenders —physical vs chemical vs mineral sunscreen — to give you the science behind them.

What is sunscreen, and why is it so important?

When you use sunscreen with broad spectrum protection it will filter both UVA and UVB rays. Both UVA and UVB contribute to increased skin cancer risk while UVB rays are the principal cause of sunburn.

Broad spectrum sunscreen (creams, lotions, gels, mists, and sprays) applied to your skin will reduce the effect of ultraviolet UVA rays and UVB rays on your skin.

When used regularly, sunscreens can prevent premature ageing and photodamage.

The two different types of sunscreens include:

• Absorbent: They absorb the UV energy to prevent it from reaching your skin cells. This sunscreen absorbs UVA and UVB radiation and is usually invisible when applied to your skin. This is how chemical sunscreens work on the skin.
• Reflectant: They block and reflect the light away from your skin. Ingredients used in these types of sunscreens include zinc oxide and titanium dioxide. This is how physical sunscreen works.

With Australia having one of the highest rates of skin cancer globally, it’s essential to use it every day. According to the Cancer Council of Australia, “sunscreen use is one of five important ways of reducing the risk of skin cancer.”

In 2010, long-term sunscreen use was attributed to preventing more than 1700 cases of melanoma, with over 14,000 cases of squamous cell carcinomas (a common keratinocyte cancer) being stopped because of sunscreen use.

The importance of applying sunscreen regularly was highlighted in a 2019 consensus statement for Australia and New Zealand.

After investigating the risks and benefits of using sunscreen, “the policy group concluded that people living in Australia and New Zealand should be advised to apply sunscreen to the face/head/neck and all parts of the body not covered by clothing on all days when the ultraviolet index is forecast to reach three or greater, irrespective of their anticipated activities.”

While sunscreens can reduce your chances of getting skin cancer, it’s essential to use one with a high sun protection factor (SPF). All sunscreens with an SPF factor of four and above are listed on the Australian Register of the Therapeutic Goods Administration.

The highest SPF sunscreen in Australia is SPF50+ which indicates that in laboratory conditions and when used as directed, it filters 98 per cent of UV radiation.

How much sunscreen should you apply?

A 2015 study recommends following the teaspoon rule:

• One teaspoon (5 mL) of sunscreen for the face, head, and neck
• One teaspoon each to the upper extremities
• One teaspoon each to the front torso and the back torso
• Two teaspoons each to the lower extremities
• Total: Nine teaspoons (45 mL) for the whole body

If you’re outside, sunscreen should be reapplied every two hours and reapplied after swimming or sweating.

If you use less than the recommended amount, your skin isn't fully protected from UV rays and this is when things like sunburn and skin cancer can occur.

What is the difference between chemical and mineral sunscreens?

With so many sunscreens available, knowing which ones are the best for skin types is tricky. The active ingredients in chemical sunscreen absorb the sun rays, turn them into heat and then release the heat through your skin.

Most chemical sunscreens are sheer and feel light on the skin. Mineral sunscreens, on the other hand, physically block ultraviolet radiation and use titanium dioxide or zinc oxide as their main ingredient.

Mineral sunscreen, which is also called physical sunscreen, can be gentler on the skin and is often the choice for baby sunscreens.

Over the years, mineral sunscreen has become less chalky and easier to blend into the skin and doesn't clog pores.

Some brands even offer tinted physical sunscreens that can be used as a makeup base. With a non-comedogenic formula, mineral sunscreens are a good choice if you’re prone to blemishes or breakouts or have sensitive skin.

Chemical sunscreen ingredients

Chemical sunscreen protects the body by converting UV rays into heat, which is then released from the body.

Chemical sunscreens can have a long list of chemicals that protect the skin from the sun — some of the common ingredients to look for are benzophenone, oxybenzone, octinoxate, benzotriazoles, cinnamates and PABAs.

Chemical sunscreens are generally easier to apply than mineral sunscreens and they absorb without leaving any white residue.

Modern formulas of chemical sunscreen are a good option if you:

• Play sports and sweat a lot
• Enjoy swimming and need a water-resistant sunscreen
• Want to use a sunscreen that absorbs quickly into your skin.

The main active ingredients in physical sunscreens are titanium oxide and zinc oxide. They can be less irritating to the skin but can feel heavy because they don’t blend as well as chemical sunscreens.

What are the pros and cons of physical sunscreen?

Physical sunscreen has mineral ingredients like zinc oxide and titanium dioxide. These sunscreens are better suited if you have acne-prone or sensitive skin. Some brands offer tinted and matte versions, which are easier to blend into your skin.

Where chemical sunscreen is light and blends easily into the skin, mineral sunscreens can be quite thick and leave a white cast on the skin, requiring thorough blending.

A 2015 study found, “titanium dioxide and zinc oxide provide UV protection primarily via absorption of UV radiation and not through significant reflection or scattering".

In non-science jargon, this means these inorganic UV filters function and provide an alternate and effective category of UV filters for consumers to choose as a sunscreen.

What are the pros and cons of chemical sunscreens?

Chemical sunscreen filters have active ingredients that are non-natural and chemical compounds.

The ingredients in chemical sunscreens are effective because they absorb the sun’s UV rays and the chemical UV filters dissipate them via a chemical reaction.

This means that UV rays never hit your body, therefore protecting your skin. But before these chemicals offer any UV protection, your skin must absorb them. For people with sensitive skin, chemical sunscreens can cause discomfort and irritation.

This type of sunscreen uses chemical filters to absorb UV light, are suitable for all skin tones, offer effective broad spectrum protection and feels lighter on the skin than mineral or physical sunscreens.

Is one better than the other?

One of the best ways to avoid UV light and sun exposure is to stay out of harmful UV rays.

Physical and chemical sunscreens with a high SPF will help protect you from the sun's rays — the only difference is the way they do this. Look for brands with broad spectrum protection that absorb UVA and UVB rays.

Your choice of sunscreen will depend on your skin type and whether you prefer a light or heavier finish.

For those who wear makeup regularly, you might find chemical sunscreens work better under products while mineral sunscreens can feel thicker and not layer as well with makeup.

If you’re unsure if the sunscreen is right for you or you're worried about your sensitive skin reacting to the product, get a few different samples and dab them on your wrist for a few days.

If no reaction develops, you’ll probably be okay to use them on your face.

The main takeaway here is that any sunscreen is better than no sunscreen and protecting yourself from harmful UVA and UVB rays is the most important thing.

Photo credit: Getty Images