Beyond the SPF Label

Not all sunscreens are created equal. While SPF ratings tell us how effectively a product protects against UVB radiation, they reveal very little about the ingredients used to achieve that protection. 

From chemical UV filters commonly found in pharmacy and supermarket sunscreens to mineral alternatives formulated with zinc oxide, there are important differences worth understanding, particularly when choosing products we apply to our skin every day.

At SIHA, our approach to sun protection extends beyond SPF. We consider the science behind the
ingredients, their compatibility with the skin and the evolving research surrounding their use. 

How does chemical sunscreen work?

Chemical sunscreens use organic UV filters that absorb ultraviolet radiation and convert the absorbed energy into heat, which is then released from the skin.

Common chemical UV filters include avobenzone, octocrylene,
octinoxate, oxybenzone and homosalate. These ingredients are widely used in conventional sunscreen formulations, often because they allow for lightweight textures and an invisible finish.

However, not all chemical UV filters have the same safety profile, and some have attracted increasing scientific scrutiny regarding their absorption through the skin and potential effects on the body.

Understanding Homosalate

Homosalate is one ingredient that has raised particular questions.  It is a UVB filter used in may sunscreen formulations.

Research has identified potential endocrine activity, raising questions about whether certain levels of exposure could interfere with the body's hormonal systems. In 2021, the European Commission's Scientific Committee on Consumer Safety assessed homosalate following concerns about its potential endocrine-disrupting properties.

This ultimately led to tighter European restrictions on its use, including limiting its concentration to 7.34% in specified facial products. Australia's Therapeutic Goods Administration (TGA) has also reviewed homosalate.

In July 2025, it recommended additional regulatory controls on homosalate and oxybenzone following an assessment of systemic exposure and potential toxicity, particularly with prolonged and frequent application. While research has not established that normal sunscreen use causes hormonal disruption in humans, these regulatory
developments highlight the importance of evaluating ingredient concentrations, exposure and long-term use.

For products we apply daily, often across large areas of the body and to our children, we believe these are considerations worth taking seriously.

How does mineral sunscreen work?

Mineral sunscreens, also known as physical sunscreens, use zinc
oxide, titanium dioxide or a combination of both to protect the skin against UVA and UVB radiation.

Unlike organic chemical filters, mineral UV filters are particles that remain predominantly on the surface of the skin. They protect
primarily by absorbing ultraviolet radiation, while also reflecting and scattering a smaller proportion of UV rays.

Zinc oxide is particularly valued for its broad-spectrum protection and generally good skin tolerability. For those experiencing sensitivity, irritation or a compromised skin barrier, a well-formulated mineral sunscreen can be an excellent choice.

Mineral sunscreens were once associated with thick textures and a noticeable white cast. However, advances in formulation have made modern mineral SPF products considerably more sophisticated, with lightweight textures and improved cosmetic finishes.

Of course, the UV filter is only one part of a sunscreen. The complete formulation, including preservatives, fragrance and supporting ingredients, also influences how a product interacts with the skin.

Why we choose mineral sunscreen

As a qualified Corneotherapist, I believe sun protection should be considered in the context of overall skin health, rather than SPF performance alone.

At SIHA, we favour mineral sunscreens formulated with zinc oxide and carefully selected supporting ingredients. We prioritise broad-spectrum protection, skin compatibility and formulations free from artificial fragrance, while remaining informed by emerging ingredient research.

Our selection process considers not only what a product contains, but how it performs, how it feels on the skin and whether it is appropriate for consistent daily use. We believe choosing sunscreen should be an informed decision, particularly when selecting products for ourselves and our families.

Because protecting the skin from the sun shouldn't come at the expense of supporting its health.

Explore our considered curation of mineral sun protection.