Sun protection is very important to prevent sun burns, skin cancer and the aging of skin. The sun releases a broad spectrum of electromagnetic radiation. We will focus on Ultra Violet Radiation (UV) and high energy visible light (HEV).
UV radiation includes: UVA and UVB. UVB sun damage is linked more to the development of skin cancer while UVA sun damage is linked more to the development of skin aging. HEV is also called blue light and is mainly emitted by the sun but is also emitted from artificial sources, which include LED and fluorescent lights and digital devices.
There are 2 forms of sun screen: organic and inorganic. Organic sunscreens are also called “chemical” sunscreens. These sunscreens absorb the UV radiation and convert it to a non-harmful amount of heat. If you look at the active ingredients on the back label you will see names like: Octinoxate, Oxybenzone, Avobenzone. They absorb well into the skin without leaving a heavy/greasy feeling or visible film. The upside is the elegance on the skin however there is a gray area in safety and also a higher risk for allergic skin reactions.
Inorganic sunscreens are also called “mineral” sunscreens. These consist of zinc oxide and titanium dioxide. These ingredients are thought to either scatter and/or reflect UV radiation preventing it from causing damage to the skin. Mineral sunscreens are notorious for leaving a white visible layer on the screen. Advancements in nano-technology have improved this issue so there is a less visible white film after application. These sunscreens tend to feel heavier and greasier on the skin and are much more noticeable after application. The upside is safety; however, they are not the most elegant sunscreens.
Tinted sunscreens are a form of mineral sunscreen that contain iron oxides which prevent damage from visible light (HEV/blue light) along with UV radiation. They are made in various formulations for lighter or darker skin tones. They are a combo of makeup and sunblock. They benefit people who are prone to developing dark spots on their skin, which can also be caused by exposure to artificial light sources.
SPF stands for sun protective factor. This is the strength of the sunscreen. We recommend patients to use 30 SPF or higher. Some people, depending on their skin type, may have to use 50 SPF or higher to prevent sun burns. Another important word to look for on the label is “broad spectrum.” This means it has protection against UVA and UVB radiation.
Sunscreen should be applied 15-30 minutes prior to sun exposure and using the appropriate amount is crucial.
When using lotion, the average adult would need a one oz shot glass-worth to apply to the exposed skin. The teaspoon rule can also be applied for individual body parts. One teaspoon for the face and neck, two teaspoons for the front and back of the torso, one teaspoon for each upper extremity and two teaspoons for each lower extremity.
Regardless of the water or sweat resistance labeling on sunscreens, it is recommended that sunscreens are reapplied after water contact or sweating. Using these rules is hard with the popular spray sunscreens. Spray sunscreens are harder to evenly coat body parts leaving some areas of the body with much less sun protection prone to sun burns.
I have patients who are concerned with the safety of sun block ingredients due to hearing they can cause cancer, disrupt hormones or damage coral reefs. With current information obtained from studies, the FDA believes that current sunscreen ingredients available in the US market are safe. Here is my two cents. Based on studies we know that mineral sunscreens are the safest. Even with new nanoparticle technology, the penetration of these ingredients past the top layer of skin is negligible, without systemic absorption. Zinc oxide can safely be used down to the age of 6 months. When it comes to the safety of organic or chemical sunscreens, there is a potential gray area. Current studies have shown that after proper application of sunblock to 75% of the body every 2 hours for 4 applications daily for 4 days straight, ingredients were detectable in blood at levels higher than the FDA threshold. With this information it seems that chemical sunscreens may penetrate into the blood, but the significance of this still needs to be determined. It should also be noted that most people do not practice sun protection as compliantly as those who were in the study. Therefore it is possible that most people would not apply enough sun block to obtain unsafe levels of the ingredients in the blood, especially if one was just using daily applications on the face. As of current, there are no strong studies supporting sunscreen and a negative impact on hormones.
Those who are also concerned about sunscreen and its effects on Vitamin D will be happy to know that when sunscreen is used in real life settings, according to current studies, there is most likely no real impact on Vitamin D levels. There is also concern with chemical sunscreens and its effects on the coral reef. Studies that were performed in laboratories have shown potential for coral damage; however, there is no real world evidence of any real damage to coral or the ocean environment caused by sunscreen ingredients.
Finally when it comes to skin cancer, we know that regular sunscreen use does not increase the risk of skin cancer but, yep you guessed it, lowers the risk of developing skin cancer.
If sunscreen isn’t your cup of tea, that’s okay. You can avoid the sun, stay in the shade or wear sun protective clothing. Look for clothing with a UPF factor between 30-50. Be careful because not all clothing protects you the same. Don’t assume just because clothing is covering your skin that you will properly be protected from the sun.
My final thoughts are that sunscreens do more good than we know they do bad. Just because there are gray areas of safety with sunscreen, doesn’t mean you shouldn’t wear any. Mineral sunscreen even though it is not the most elegant has the strongest track record when it comes to safety. Don’t forget to reapply and don’t forget to seek shade and wear sun protective clothing whenever possible. Keep these sun protective methods in mind especially between 10AM-2pm when UV exposure is at its peak.
