Sunscreen is essential to good skincare and general health. It protects you from harmful UV rays, which prevents inflammation, irritation, premature signs of aging and skin cancer. However, some ingredients found in common commercial sunscreens may harm your health by disrupting your hormones or causing allergic reactions. Learn more about the safest sunscreen ingredients below.
Physical vs. Chemical Sunscreens
The active ingredients in sunscreens can be broken into two groups, physical and chemical sunscreens. Physical sunscreens are commonly made from mineral-based ingredients such as zinc oxide and titanium dioxide, which work to physically block and reflect UV rays to prevent them from penetrating the skin. By comparison, chemical sunscreens absorb UV rays, converting them into heat that dissipates out of the body.
Physical sunscreens tend to be more popular than chemical sunscreen because they have been thoroughly tested by the FDA and deemed safe for humans and the environment. Another positive is that physical sunscreens work immediately on application, whereas, chemical sunscreen need to be applied 15 minutes before sun exposure. In addition, physical sunscreens tend to not clog pores compared to chemical sunscreens. The cons of physical sunscreens are that they are less water resistant and leave a white cast, which can be a concerned among darker tones individuals.
Many sunscreen producers have turned to chemical ingredients as they are lighter and easier to spread and wear without leaving a white cast like mineral sunscreens. However, chemical sunscreens are known to break down over time, which reduces their protection and reliability. Furthermore, as chemical sunscreens break down, the ingredients create byproducts that absorb into the skin and build up in your system. These byproducts may disrupt hormones and endocrine functions. Another important difference is that chemical sunscreens are also more likely to cause irritation and allergic reactions.
UVA vs. UVB Radiation
Along with the different types of sunscreen, it’s important to understand the two different forms of UV radiation. Sunlight emits UVA and UVB radiation.
UVA rays are the more prevalent of the two forms of radiation. Sunlight is estimated to have 500 times more UVA rays than UVB rays. UVA rays are known to penetrate deeper into the skin, contributing more commonly to signs of aging, while UVB rays affect the surface of the skin and cause of sunburns.
While UVB rays play a larger role in skin cancer, both UVA and UVB rays can contribute to skin cancer formation, making it important to protect against both forms of radiation.1
The Best Sunscreen Ingredients to Look For
Zinc Oxide
Zinc oxide is a gentle mineral-based, physical filter ingredient, so you do not have to worry about it penetrating your skin. It offers effective protection for both UVA and UVB rays.2 According to the Environmental Working Group, zinc oxide is one of the safest cosmetic ingredients used in sunscreens.3
Because it’s a mineral-based ingredient, zinc oxide may leave a white or opaque cast when applied, but you can usually prevent this by making sure you rub the sunscreen in properly. Alternately, look for clear or micronized formulations.
Titanium Dioxide
Another mineral-based ingredient, titanium dioxide is frequently coupled with zinc oxide and is considered one of the safest ingredients from the EWG.4 While titanium dioxide is highly effective in protecting against UVB rays, it offers only partial protection from UVA rays.2
Avobenzone
Avobenzone is a chemical sunscreen ingredient that offers broad spectrum protection that blocks both UVA and UVB wavelengths, making it one of the few to protect against both forms of UV radiation. When combined with other photostabilizing ingredients, avobenzone can provide long-lasting and stable protection. There is no evidence to suggest that avobenzone is toxic, and it is typically non-irritating.5
Octisalate
Octisalate is another chemical filter. It is effective in protecting against UV rays, but it is most commonly used as a stabilizer for avobenzone. It is generally safe for use and not currently known to disrupt hormone production.
Mexoryl SX (Ecamsule)
Mexoryl SX is FDA-approved for only certain sunscreen products and is most effective in blocking UVA wavelengths.6 Mexoryl SX is most novel for being a chemical filter that is highly water resistant and maintains photostability, meaning that it undergoes limited breakdown following sun exposure.7
Common Ingredients to Avoid
PABA (Para-Aminobenzic Acid)
PABA is an ingredient that is known to cause allergic reactions and stain your clothes. Research also indicates that PABA has carcinogenic potential.8 Thankfully, while PABA was formerly common, it is generally not found in sunscreens today due to the known health concerns.9
Homosalate
Homosalate may disrupt hormones and endocrine function. Furthermore, sunlight is known to break homosalate down into potentially harmful byproducts.10
Octinoxate
Octinoxate has been shown to disrupt hormones. Some animal studies even show that octinoxate may have hormone-mimicking effects.11
Oxybenzone
Oxybenzone is one of the most common chemical ingredients used in modern sunscreens, but it presents a variety of potential health issues. It has high skin absorption, causes allergic reactions, and shows powerful anti-androgenic effects.3
Sunscreen plays an integral role in preventing skin cancer, skin damage and signs of aging. Physical sunscreens that use mineral-based ingredients are generally preferred, as they don’t degrade or get absorbed into the skin the way that chemical sunscreens do. A sunscreen should be at least SPF 30 and provide broad spectrum protection for both UVA and UVB rays. Wear sunscreen every day, even when it’s cloudy, even when you are indoors, and reapply every two hours.
Sources:
- https://uihc.org/health-topics/what-difference-between-uva-and-uvb-rays
- https://theskincareedit.com/2017/06/02/how-to-choose-best-sunscreen
- https://www.ewg.org/sunscreen/report/the-trouble-with-sunscreen-chemicals/
- https://www.ewg.org/sunscreen/report/nanoparticles-in-sunscreen/
- https://www.aad.org/practicecenter/managing-a-practice/media-relations-toolkit/dermatology-issues-in-the-news/frequently-asked-questions-about-avobenzone
- https://www.ewg.org/skindeep/ingredient/706484/MEXORYL_SX/
- https://www.ncbi.nlm.nih.gov/pubmed/17805138
- https://www.ewg.org/skindeep/ingredient/704390/PABA/
- https://oureverydaylife.com/134435-what-is-paba-sunscreen.html
- https://www.ewg.org/skindeep/ingredient/702867/HOMOSALATE/
- http://www.ewg.org/skindeep/ingredient/704203/OCTINOXATE/
About the Author:
Dr. Bryan Do, D.O. is an osteopathic physician whose research interests include gastroenterology, immunology, and dermatology. He is particularly interested in the role of probiotics in the gut-brain-skin axis and has written many articles on the topic. He graduated from University of California, Los Angeles (UCLA) before graduating from Marian University College of Osteopathic Medicine in Indianapolis, Indiana and becoming a Doctor of Osteopathic Medicine. Osteopathic physicians are taught to take a holistic approach to medicine and to consider mind, body, and spirit when treating a patient. Osteopathic physicians receive training in Osteopathic Manipulative Medicine (OMM) in addition to the standard rigorous medical school curriculum. Both physicians with a Doctor of Osteopathic Medicine (D.O.) degree as well as a Doctor of Medicine (M.D.) can practice medicine.