Zinc oxide in physical SPF products

We all know that UV radiation is the number 1 cause of skin ageing. Your skin remembers everything: every time you have a quick drink on the terrace unprotected, or don’t use SPF protection in winter because ‘the sun isn’t shining anyway’. Over time, unprotected skin starts to show sun damage in the form of premature ageing, wrinkles, hyperpigmentation and skin cancer. To limit the signs of premature skin ageing, it is important to protect your skin daily with SPF protection. But if you have sensitive skin, finding skincare with SPF can be a tricky task when your skin cannot tolerate skincare products with a chemical SPF..

Chemical or physical (mineral) filter?
Skincare with a UV filter can be divided into chemical (absorbing) and physical (reflecting) filters. Products with chemical filters are absorbed by the skin: they sink into the skin. Products with a physical (mineral) filter stay on top of the skin, so they reflect UV rays. This drives warm energy away from the skin, which is perfect for people who suffer from redness or rosacea. Because the physical SPF also does not sink into the skin, the chance of skin irritation is smaller and they are mainly suitable for people with (very) sensitive skin or whose skin has recently been exfoliated.

What is zinc oxide and how does it work?
Most skincare products with a physical SPF contain zinc oxide. Zinc oxide is a mineral or oxidised form of the metal zinc. In chemical terms, zinc oxide (ZnO) is a zinc atom and an oxygen atom held together by an ionic bond. As a UV filter, zinc oxide stays on top of the skin and works by reflecting light. This provides broad-spectrum protection against sun damage, which means your skin is protected against both UV-A and UV-B rays. Because zinc oxide does not sink into the skin but stays on it like a shield, this mineral UV filter rarely causes an allergic reaction. 

Why a physical SPF leaves a white cast
Zinc oxide particles can be quite large, which is why they leave a visible white cast on the skin. This is also why a physical SPF is often not suitable for all skin tones. Thanks to scientific developments, it is possible to develop this ingredient into smaller particles using micro technology for an invisible finish.

Dermalogica’s solution to a white cast
To create Invisible Physical Defense SPF30 Dermalogica applied a special blending process for the perfect transparent finish on the skin. First of all, invisible zinc oxide was used, made with ultra-fine particles (dermalogica uses no nanotechnology!) blended into a polymer and vegetable oil. This careful blending procedure is crucial in ensuring that the particles do not clump together. The mixture also provides a more even distribution on the skin, which further contributes to its transparency. The rest of the formula is then developed around the mixture so as to keep guaranteeing this optimal distribution. This makes the physical SPF suitable for all skin tones, including a dark skin tone.