Chemical VS Physical SPF

Sun damage accounts for 90% of visible signs of aging. Daily use of sunscreen can prevent skin cancer and reduce signs of extrinsic aging. There are two categories sunscreen can fall under – Chemical Sunscreen and Physical Sunscreen – both behave and protect the skin in different ways.

Physical Sunscreen contains Titanium Dioxide or Zinc Oxide. Titanium Dioxide and Zinc Oxide act as physical barriers by creating a layer of microscopic “mirror” particles that reflect UVA and UVB rays. Titanium and Zinc are both metals, which bond to Oxygen Atoms to form naturally-occurring stable compounds. These compounds do not behave like free radicals, meaning – these compounds do not harm healthy cells. Physical sunscreen creates a physical barrier that sits on top of the skin. Titanium Dioxide and Zinc Oxide are composed of large particles that do not penetrate the skin. Physical sunscreen is preferred for those with sensitive skin or acne, since it does not irritate or react with skin.

Chemical Sunscreen behaves differently and contains one (or more) of the following ingredients – avobenzone, oxybenzone, octinoxate, octisalate, and/or octocrylene. Chemical sunscreen reacts with and absorbs UV energy, converting it into the form of heat, released back into the body. Chemical Sunscreen is absorbed into the skin and actually enters your blood stream. Pregnant and breastfeeding women beware! Use of Chemical Sunscreen while nursing results in contaminated breast milk. Certain Chemical Sunscreens (oxybenzone) can affect testosterone and other hormonal levels.

Which Sunscreen is right for me?

With my esthetics education and experience, I recommend Physical Sunscreen over Chemical Sunscreen in most situations. Physical Sunscreen is less invasive, less likely to break you out or cause a reaction, and is suitable for all skin types. However, there are some situations where Chemical Sunscreen may be more appropriate – for example, when applying sunscreen all over the body, it may be more convenient than having to rub in mineral sunscreen (which can leave an opaque white film) all over the body. Make sure to apply Chemical Sunscreen 15-30 min before sun exposure, and to be reapplying after contact with water.

How often should I be applying sunscreen?

The FDA recommends reapplication of sunscreen – regardless of type of sunscreen – every 2 hours. If you are exposed to water or sweating, you may need to reapply more frequently. In general, if I know I’m going to be inside working all day, I will apply SPF in the morning and that’s it. If I’m going hiking, I will apply SPF in the morning, when I get to the trailhead, and I will bring extra sunscreen in case we are going to be out for more than 2 hours. I recommend using a high-quality sunscreen for the face, but I find that drugstore sunscreen is just fine for the body.

What else can I do to protect my sun from the skin?

If you know you are going to be outside for several hours, bring a hat. If you are not in the habit of wearing SPF daily, keep a sunhat in your car. For those who work indoors, your biggest exposure to the sun is while you are driving. Glass blocks UVB rays, but still allows UVA rays to pass through. It is important to vigilantly protect yourself from future aging and skin cancer. Especially here in Denver, we are at a Mile High elevation, and closer to the sun than the rest of the world.

I personally use and recommend Sanitas Solar Block, which is a broad-spectrum Physical Sunscreen (SPF 20). SPF 30 is ideal and recommended – for outdoor excursions I would probably use something stronger – but for daily use, I love the light feeling of Sanitas Solar Block. I use Hempz Body Moisturizer with SPF, which is a Chemical Sunscreen, for larger areas of the body.

You might want to learn more about Marine Life and SPF.