The active component of first sunscreen consist of zinc oxide. Zinc oxide acts as a physical barrier that sits on the surface of your skin; it offers the same protection as wearing a long sleeve shirt. Because it is not absorbed into the skin, it is nonirritating, non-allergenic, and non-comedogenic. Since you are left with a pasty white substance all over your skin with each application, aesthetically, zinc oxide is a disaster.
Common commercial sunscreen unlike zinc oxide formulations, which sit on the surface of your skin, they are partially absorbed through the skin. This means that any harmful ingredients in your sunscreen will have a systemic effect. Parabens can antagonize androgens (testosterone) and wreaks havoc on your body’s hormones. Oxybenzone and retinyl palmitate are two other harmful ingredients contained in many sunscreen products.
Now researchers at Yale University have used nano-particles to develop a new type of sunscreen that can not penetrate the skin, effectively overcoming lot of the health concerns associated with chemical sunscreens. Even better, it’s clear and water resistant, and in animal models it’s been shown to be just as effective as protecting against sun damage. It doesn’t come off, and more importantly, it doesn’t penetrate any further into the skin. The sunscreen works by using nanoparticles that have a rich coating of aldehyde groups, which makes them stick eagerly to the outer layer of our skin. This coating also locks in the active ingredient of the sunscreen, a hydrophobic chemical called padimate O, stopping it from being directly exposed to the skin. It also stays on the skin for days, even after being exposed to water, but came off completely when rubbed with a towel. This new nanoparticle sunscreen will need further testing on humans before it’s able to be released commercially.