“If I Could Offer You Only One Tip For The Future, Sunscreen Would Be It” - goes the famous song, attributed by an urban legend to a 1997 commencement speech by author Kurt Vonnegut at MIT (which never happened.)
But if we could dispense our one advice, “Wear a Zinc Oxide Sunscreen and forget about Oxybenzone” would be it.
In 2019 the U.S. FDA dropped a bomb proposing almost all FDA-approved sunscreen ingredients are either unsafe, or uncertain until further analysis. Then in 2020, the FDA demonstrated that 6 of the most popular sunscreen filters get absorbed into the bloodstream at a very high concentration, even after a single use, and some of them can stay inside our body for weeks. The FDA was supposed to finalize its safety review last year, but industry pressure, followed by COVID-19 awkward legislation, are slowing the process (more on that below).
Meanwhile, the only two safe and effective sunscreen filters, according to the FDA’s proposed rule, are the minerals zinc oxide and titanium dioxide.
Before we give you the lowdown on what this means for you, we’d like to reiterate the bottom line. Don’t stop using sunscreen. Just make sure it’s got the right ingredients.
Spoiler: use non-nano, non-spray, zinc oxide.
Skin cancer is the most commonly diagnosed cancer in the US, and the rate of melanoma, the deadliest type, has been rising for the last 30 years. The American Cancer Society’s estimates that in 2019 over 96,000 new melanoma cases will be diagnosed, and over 7,000 people are expected to die of it .
Skin cancer is mostly the result of exposure to ultraviolet (UV) radiation. “Ultraviolet” because its wavelength spans beyond the visible violet sunlight. The UV radiation spectrum can be divided into three components: UVA, UVB, and UVC, and getting to know each of them will help you understand how to protect yourself effectively:
The SPF number (Sun protection factor) that you see on sunscreen labels measures how much of the UVB radiation is blocked. For example, SPF 30 means that 1/30 (3.3%) of the UVB radiation will hit your skin, and the remaining 96.7% will be blocked by the sunscreen. Here’s another way to think about this: if you your unprotected skin gets burnt within 5 minutes, applying an SPF 30 sunscreen means you’ll get the same sunburn within 5 minutes x 30, or within 150 minutes. In comparison, an SPF-50 sunscreen will let 1/50 (2%) of the UVB radiation hit your skin, and block the remaining 98% of UVB radiation. Remember that these protection factors are relevant only as long as the sunscreen is applied liberally and isn’t washed away by sweat, water or your towel.
You might be surprised to learn that SPF measures only UVB protection, and doesn’t mean anything about UVA protection. In other words, some active sunscreen ingredients can block UVB very well, but let harmful UVA radiation pass freely.
Now that we understand that both UVA and UVB can cause cancer, it’s clear why it’s critical to choose Broad Spectrum sunscreens that protect against both UVA and UVB, and not only UVB-blocking sunscreens.
Once more: high SPF is not enough - if your sunscreen is not a Broad Spectrum sunscreen, it means even the manufacturer doesn’t claim that it blocks UVA from damaging your skin.
“Active” sunscreen ingredients can protect our skin from UV rays in two different ways:
In February 2019 the U.S. FDA published a quite dramatic proposed rule to update the regulation of sunscreens. It’s a 70 page document  with hundreds of scientific references, so let me summarize the bottom lines for you.
The FDA reviewed all the 16 FDA-approved sunscreen active ingredients and divided them into three groups:
That’s right. All the FDA-approved chemical active ingredients used in the US today belong to the FDA’s third group, which means that the FDA would need additional data to determine that sunscreens with these ingredients would be safe and effective.
The FDA has already collected over 20,000 inputs from the public and the industry, and the review process is still going on.
In a written response to our inquiry, the FDA’s Center for Drug Evaluation and Research explained how COVID-19 regulation has impacted the timeline for a final rule regarding these sunscreens. The FDA stated: "In March of 2020, the Coronavirus Aid, Relief, and Economic Security (CARES) Act was passed, which included provisions that changed certain aspects of how OTC monograph drugs are regulated. Among other things, this new law replaced the rulemaking process previously used to establish OTC monographs with an order process. For the sunscreen monograph specifically, the CARES Act requires that FDA issue a proposed order for sunscreens by September 27, 2021. CARES does not impose a deadline for issuance of a final sunscreen order, but it does specify that the final sunscreen order cannot go into effect earlier than one year after its issuance."
- Until then the regulation doesn’t change, but consumers should of course use their common sense.
In March 2021 scientists discovered that octocrylene, a chemical UV filter common in thousands of SPF products, degrades over time to a different compound: benzophenone . This is alarming because exposure to benzophenone may increase the risk of cancer, according to the California Environmental Protection Agency . The scientists examined 9 commercial sunscreen products from Europe and 8 from the USA and recorded benzophenone accumulation over time in these products. A separate researchers group also confirmed the presence of benzophenone in sunscreens and cosmetics containing octocrylene, through lab testing of 39 skin care products in 2021 .
Do susnscreen filters remain on the skin? or would they get absorbed into the bloodstream and affect the body systematically?
In May 2019, scientists at the FDA’s Center for Drug Evaluation and Research (CDER) researched what happens when commercially available sunscreens are used as directed by the product label. They selected sunscreens with common chemical filters (avobenzone, oxybenzone, octocrylene, and ecamsule). 24 volunteers applied sunscreen a couple of times every day, for 4 days, and their blood samples were tested daily for a week to see if any of these 4 active ingredients had penetrated the skin and reached the bloodstream.
The researchers found that all 4 ingredients reached the bloodstream of the participants at high concentrations. How high? By the end of the first day the concentrations already exceeded the FDA’s “safety waiver threshold”. That’s a threshold above which toxicology assessment including systemic carcinogenicity and additional developmental and reproductive studies must be carried out. The concentrations remained above that threshold even on the 7th day, 3 days after the last sunscreen application: in the case of oxybenzone it was then still over 40 times greater than the threshold. The full results were published in the Journal of the American Medical Association  and have been covered by the international media.
Then in January 2020, a more extensive clinical trial published by the FDA  tested the absorption of 6 of the common chemical filters (avobenzone, oxybenzone, octocrylene, homosalate, octisalate, and octinoxate), contained in 4 commercially available products (lotion, aerosol spray, non aerosol spray and pump spray), over three weeks.
All of the 6 chemical filters were absorbed by the skin into the body’s bloodstream at a very high concentration, even after a single use. Some of these chemical filters stayed inside the body at concentrations greater than the FDA’s threshold, 3 weeks after the participants stopped putting them on their skin.
Honestly, the revelation that chemical filters pass through our skin shouldn't surprise anyone. Back in 2004, scientists of the U.S. Centers of Disease Control and Prevention of the U.S. Department of Health have sampled the urine of 2,517 Americans aged six year and older and discovered Oxybenzone in 97.6% of the samples . Oxybenzone and other chemical filters like octinoxate have been detected in human breast milk too - in Germany (over 20 years ago!) , Switzerland , and Spain , with sunscreens being a possible source.
At this stage the FDA does not say that chemical filters are harmful or should be avoided. It simply points out that these sunscreen ingredients enter our body and that there is a question mark around their systemic impact which must be analyzed before they can regain the FDA’s “safe and effective” status.
But if you ask scientists focusing on the research of Endocrine Disruptors (chemicals that may interfere with the proper function of our hormones) the answer is clear. Oxybenzone, octinoxate, and other UV chemical filters have been linked to hormone disruption, including harming the proper function of the female hormones in animals, their fertility and the neurological development of their offsprings [8, 15]. Exposure to oxybenzone during pregnancy was recently shown to damage neurons and the affect the developing brain of the fetus in mice . Oxybenzoe, homosalate, and other chemical filters were also shown to interfere with functions of human sperm , and oxybenzone has been associated with lower testosterone levels in adolescent boys .
There's more. Mix oxybenzone with chlorine, which is commonly used as a swimming pool disinfectant, and you get an altered chlorinated-oxybenzone, which according to some studies  is dramatically less effective in UV blocking, and at the same time more toxic to our cells. Avobenzone, another very common chemical UV filter, was also reported  to produce toxic compounds when transformed by pool disinfectants (sodium hypochlorite), and so does octinoxate, which chlorinated byproducts were shown to create mutations in cells .
Another troubling aspect of oxybenzone and other chemical filters that is making waves in recent years, is their destructive impact on coral reefs and marine life. Studies  have discovered that oxybenzone can damage coral DNA, cause deformation in growing baby coral, and increase the rate of coral bleaching. The U.S. National Oceanic and Atmospheric Administration (NOAA) warns that sunscreen filters can also harm fish, algae and other sea creatures, which in turn endanger the species that rely on them as a source of food. How does oxybenzone get to the sea in the first place? It is simply washed off swimmers and discharged into the sea by wastewater facilities. It’s true that sunscreen is only one contributor to the pollution of the sea and the dying reefs, but these contributions add up.
Do mineral filters pose a risk to the oceans? Apparently it’s a question of size. The mineral filters used in sunscreens, zinc oxide and titanium dioxide, can be either made of nano-sized particles (particles smaller than 100 billionths of a meter), or made of bigger non-nano particles. Multiple scientific researches  have concluded that mineral filters, both nano-sized and non-nano sized, remain on the human skin’s surface, do not reach viable skin cells and do not reach the bloodstream.
While nano-sized mineral filters in sunscreen lotions seem safe for humans, this may not be the case for marine life. Dr. Craig Downs, executive director of the Haereticus Environmental Laboratory told Clearya: “nano-particles of the mineral oxides can cause toxicity to coral, fish, and marine invertebrates.” As for non-nano sized mineral filters, Dr. Downs explains: “Zinc Oxide, if it non-nanotized, is relatively safe for coral and fish.”
While the scientific evidence associating common chemical filters with potential hormone disruption and environmental damage continue to accumulate, consumers should choose whether to take part in this experiment or opt for using mineral filters, which at this time are the only two active ingredients determined as safe and effective by the FDA’s proposed ruling.
If you go for mineral filters, choosing a sunscreen becomes a relatively simple task:
We prefer the non-nano form of zinc oxide and titanium dioxide, although according to the FDA’s review of recent scientific literature , the physical properties of zinc oxide and titanium dioxide prevent their absorption through the deeper layers of the skin in any meaningful extent, even when applied at the maximum 25% concentration, and regardless of their particle size.
We focused here on Active ingredients, but sunscreens, like other skin care products, often contain tens of other Inactive ingredients, such as parabens (preservatives), phthalates (common ingredients in synthetic fragrance) that are also linked to hormone disruption, certain cyclosiloxanes (associated with reproductive harm), and sometimes have chemical filters listed under different names, adding to the confusion.
So if you feel you need an extra pair of eyes to quickly scan the ingredient list for you, simply use the Clearya iPhone app, Android app, or Chrome extension to automatically check your sunscreen's ingredients safety, while you shop online.
Disclaimer: the content in this blog post is provided for general information, and does not substitute any medical advice by your own doctor or another health care professional.