Dissecting Sunscreen Labels – How to choose a safer sunscreen for yourself and the planet with Sarah Janssen, MD

July, 2018 – Sunscreens contain dozens of chemicals to protect our skin from damaging sun rays. Unfortunately, many of these chemicals are also linked to harmful health effects such as endocrine disruption and cancer. Other chemicals in sunscreens are toxic to coral reefs. Physician and researcher Sarah Janssen joined us Around the Table to discuss choosing safer sunscreens and protecting ourselves from the sun’s rays. Here’s what she had to say:


Use sunscreen as a last resort. Since most sunscreens do not block UVA rays, sunscreen does not necessarily prevent skin cancer. “Even if you use an SPF of 100, it doesn’t mean it is effective against UVA,” said Sarah.


Look for sunscreens with UVA/UVB block and SPF 30 or higher, but no more than SPF 50. “The FDA has said there’s no evidence that anything higher than SPF 50 is effective — and it might give a false sense of security,” said Sarah.


There are two kinds of sunscreens: physical barriers and chemical barriers.

Physical barriers (mineral sunscreens using zinc oxide and titanium oxide) sit on the skin and block rays. They are safer than chemical barriers for our bodies and for the ocean.

Chemical barriers are absorbed into the skin and into the bloodstream. Chemical barriers contain hormone disruptors which can cause cancer, and they damage coral reefs. It is estimated that 14,000 tons of Oxybenzone are put into oceans per year from sunscreens. The chemical bleaches coral reefs and effects their DNA so they can’t reproduce. Hawaii recently banned sunscreens with Oxybenzone and Octinoxate.


Say no to spray sunscreens.

Not a lot of research has been done on popular aerosol sunscreen sprays. “Aerosol spray sunscreens have not been tested for their effects on lungs, just on skin,” said Sarah. “With aerosol, you inhale the chemicals straight into the lungs. Even with natural mineral sunscreens, zinc and titanium are metals and are carcinogenic when inhaled.”


‘Nano zinc oxide’ is a safe bet.

Nano zinc oxide (or micronized zinc) sunscreens are a popular choice because they are mineral based, but look clear on the skin. The physical barrier is still there, but you can’t see it. Research done by the Environmental Working Group shows that nano zinc oxide is not absorbed into the body. The particles are still too big to enter the bloodstream, and they are not fat soluble.

“Remembering that sunscreen is a last resort, Nano zinc oxide is a safe choice as long as it is not sprayed,” said Sarah.


Pro tip: Sarah recommends Environmental Working Group’s app called Healthy Living. It gives you quick access to EWG’s safety ratings on 128,000 personal products. The app lets you scan bar codes or search for a product by name.


Sarah Janssen, MD, PhD, MPH, has a broad background in reproductive physiology, clinical medicine and public health. She has over 20 years of experience studying a number of toxic chemicals, including hormone-disrupting substances which interfere with fertility and reproduction. Dr. Janssen is a physician in the Occupational Medicine Department of the Permanente Medical Group in San Francisco. She is board certified in Preventive Medicine, completed her MD and PhD in Reproductive Physiology at the University of Illinois, Urbana-Champaign and did her residency training at UCSF. She has a MPH in Environmental Health Sciences from the University of California, Berkeley.