Physical vs. Chemical Sunscreens

Do you know what is really happening to our skin when it is hit by UVA and UVB rays? The shorter UVB rays do the majority of damage in the top layer of our skin called the epidermis – these rays are responsible for majority of suntans and burns. Longer UVA rays do the majority of damage in the second layer of our skin the dermis.  I like to remember them as UVA (Age) and UVB (Burn). The dermis is where all our collagen and structural elements reside.   When energy of these small particles of light strike our skin (where the light wave stops), the energy released alters the chemistry of that component of the skin and damages it.  This is the initial damage.  These chemical changes also produce free radicals and these radicals continue on to cause additional damage (secondary damage) to other skin components.  

 In time this repetitive photo-damage and free radical damage will break down collagen and elastin.  Your pigment cells called melanocytes become dysfunctional and produce volumes of pigment that result in age spots and other forms of pigment (hyper and/or hypo).  The fibroblast cells stop producing new collagen leaving your skin slack.  

It is estimated that 90% of sun damage is the result of unplanned or casual sun exposures when people may not have active photo-protection.  This can include riding in a car,  or just going for a short walk with their dog without wearing proper sunscreen. Unfortunately, 90% of sun damage is already done by the time you are 18 years old.

            Chemical sunscreens protect the skin by absorbing the light particles.   When this energy is absorbed, the molecules of the sunscreen are destroyed, rather than a skin component but this still results in chemical reactions (usually producing heat in the skin that can lead to irritation).Subsequently chemical sunscreens are not the most complete or effective form of sun protection. They prevent a larger degree of the initial sun damage but allow secondary free radical damage, which adds to the speed of the skin ageing process.

            Physical sunscreens on the other hand such as zinc oxide and titanium dioxide work by reflecting the photons of light up and out of the skin so there is no absorption of energy.  There is no chemical reaction and no free radicals are produced.  

            A physical sunscreen is a crucial part of anti-aging and skin health. Look for products that contain zinc oxide and titanium dioxide as their SPF. My all time favorite product line is Colorescience (obviously). I have mentioned this product in previous posts. I don’t leave the house without it, no matter what the weather is like outside. It comes in the form of a mineral make up as well as a translucent or tinted powdered SPF 30.  The perks of having it in powder for, easy application, no dripping into the eyes, and it’s cooling on the skin because it reflects the UV rays instead of absorbing it and causing a chemical reaction in the skin usually producing heat. All in all it’s just an amazing, convenient product.