Chemical vs Physical Sunscreens: Less Fear mongering, More Science

By Dr Austin Lang | Master of Medicine (Skin Cancer), Bachelor of Surgery, Bachelor of Medicine, Bachelor of Science, FRACGP

Chief Medical Officer, Actaskin

When it comes to sunscreen, the debate between chemical (organic) and physical (inorganic) filters continues. Most of the arguments against chemical sunscreens are flawed by the fact that they use emotional pleas, rather than cold hard facts. While both offer effective sun protection, chemical sunscreens provide significant advantages.

What Are Chemical and Physical Sunscreens?

The active ingredients in sunscreens are divided into two categories:

• Physical (inorganic) sunscreen ingredients: Zinc oxide and titanium dioxide.
• Chemical (organic) sunscreen ingredients: Everything else, including innovative filters like Tinosorb S, Tinosorb M, and Uvinul A Plus.

In chemistry, any compound containing carbon is deemed an organic substance. Compounds without carbon, like Zinc oxide, are therefore called inorganic substances. You can have sunscreens containing only organic filters, only inorganic filters, or a combination of both.

Both types primarily work by absorbing UV radiation and converting it into heat. Some people will disagree on that point, because the physical sunscreens were initially thought to work by reflecting the UV, rather than absorbing it, which led to the ‘physical’ sunscreen moniker. This was subsequently proven to be wrong, as 90-95% of their function is in fact by absorbing UV radiation, making the term ‘physical’ incorrect. By the way, zinc oxide and titanium oxide are actually chemicals, so the whole nomenclature of ‘physical’ and ‘chemical’ is defunct. And if we all knew them by their accurate descriptors of inorganic or organic sunscreen, there would probably be a big shift in sentiment towards ‘organic’ sunscreen.

Key Advantages of Chemical (Organic) Sunscreens

1. Superior UVA Protection

Modern chemical (organic) sunscreens offer exceptional protection against long-wavelength UVA rays, which are responsible for deeper skin damage and aging. Advanced filters like Tinosorb S, Tinosorb M, and Uvinul A Plus provide high, photostable UVA coverage, outperforming traditional inorganic filters. This is particularly important for protecting against skin cancer and photoaging.

Physical (inorganic) sunscreens generally max out around a UVAPF of 20, while organic formulations can achieve UVAPF 40 or higher, giving superior broad-spectrum protection.

2. No More White Cast

One of the most common complaints about sunscreen is the dreaded white cast, especially for those with darker skin tones. Physical (inorganic) sunscreens tend to be very white (especially if they have titanium dioxide) while chemical (organic) sunscreens excel here, offering clear, lightweight formulations that absorb seamlessly without leaving a visible residue.

3. Better Texture and Wearability

Chemical (organic) sunscreens are often designed with modern skincare preferences in mind, offering lightweight, non-greasy textures that feel more like moisturisers. This makes them ideal for daily use and under makeup.

4. Better Suitability for Active Lifestyles

Because chemical (organic) sunscreens often feature water- and sweat-resistant formulations, they provide lasting protection for those who enjoy outdoor activities. Their flexible formulations are less prone to shifting on the skin during movement.

Common Myths About Chemical Sunscreens

There are plenty of myths surrounding chemical and physical sunscreens. Despite their many benefits, chemical sunscreens are frequently misunderstood. Let’s clear up some of the most common misconceptions:

Myth: You need to wait for chemical sunscreens to work

This myth from the misconception that chemical sunscreens need to absorb into your skin and bind before they’re effective. In reality, both types of sunscreen work immediately after application. What matters is that all sunscreens need to form a continuous film on your skin, and once that’s done, they’re effective—so you can apply them the same way, no matter the type.

Myth: Chemical sunscreens produce excessive heat that damages the skin

Both sunscreen types convert UV into heat. However, this heat is incredibly minimal and is quickly dissipated without raising the temperature of your skin to harmful levels.

Myth: Physical sunscreens are better because they are natural

Natural ingredients aren’t inherently better than synthetic. Furthermore, physical sunscreens aren’t actually "natural." They go through industrial processing to remove toxic contaminants and often need to be combined with chemicals to prevent them from clumping to ensure even, reliable protection.

Myth: Chemical sunscreens are hormonal disruptors

This is a nuanced topic, lets break it down.

There are many types of chemical sunscreens, and they vary in absorption rates, UV efficiency, and effects on the body. While some ingredients are linked to hormonal effects in lab studies, most modern sunscreens don’t absorb into the skin, and the exposure to these chemicals is minimal. So, we can’t make broad claims about their safety.

Concerns often arise from detecting trace amounts of ingredients like oxybenzone in breast milk and urine. However, these detection methods are highly sensitive, and finding small traces doesn’t mean there’s enough to cause harm (FYI Actaskin’s Sun Protect doesn’t contain oxybenzone). For a substance to be a real concern, it needs to have a significant effect, and tiny amounts like this generally don’t pose any risk.

Among chemical sunscreens, oxybenzone has the strongest hormonal effects in studies, but even in the worst-case scenarios, you’d need to use it for 277 years straight to see any noticeable impact. Other ingredients like enzacamene and octinoxate have similar effects, but the amounts needed to cause any harm are even higher. So, chemical sunscreens are safe when used as directed.

Bottom Line

Choosing the right sunscreen comes down to your skin's needs and lifestyle.

Most importantly, look for a sunscreen with at least SPF 30, UVA & UVB coverage and is TGA approved (look for the AUSTL number) and ensure consistent use because that is the most crucial factor in effective sun protection.

By Dr Austin Lang | Master of Medicine (Skin Cancer), Bachelor of Surgery, Bachelor of Medicine, Bachelor of Science, FRACGP. Chief Medical Officer, Actaskin

Dr Austin Lang is a skin cancer doctor renowned for his expertise in diagnosis and management, with a strong focus on prevention and patient-centered care. He leads Actaskin’s clinical strategy and product development.

Further Reading:

Popov, A. P., Priezzhev, A. V., & Lademann, J. (2007). Optical properties of zinc oxide and titanium dioxide nanoparticles for UV absorption and scattering in sunscreen formulations. Journal of Cosmetic Science, 58(6), 531–539.

Wang, S. Q., & Lim, H. W. (2017). Photoprotection beyond ultraviolet radiation: Ultraviolet A1, visible light, and infrared-A. Journal of the American Academy of Dermatology, 76(3S1), S100–S109. https://doi.org/10.1016/j.jaad.2016.08.038

Wang, S. Q., Balagula, Y., & Osterwalder, U. (2011). Photoprotection: A review of the current and future technologies. Photodermatology, Photoimmunology & Photomedicine, 27(2), 65–73. https://doi.org/10.1111/j.1600-0781.2011.00557.x

Krause, M., Klit, A., Jensen, M. B., Soeborg, T., Frederiksen, H., Schlumpf, M., ... & Skakkebaek, N. E. (2012). Sunscreens: Are they beneficial for health? An overview of endocrine disrupting properties of UV-filters. International Journal of Andrology, 35(3), 424–436. https://doi.org/10.1111/j.1365-2605.2012.01280.x

Diffey, B. L., & Grice, J. (2008). Immediate photoprotection provided by sunscreen after application. Photodermatology, Photoimmunology & Photomedicine, 24(2), 110–112. https://doi.org/10.1111/j.1600-0781.2008.00342.x

KindofStephen. (2016, September 1). "Physical" vs. "chemical" sunscreens and other sunscreen myths. KindofStephen. https://www.kindofstephen.com/physical-vs-chemical-sunscreens-myths/