The Hidden Dangers of Chemical Sunscreens: The Full List of Harmful UV Filters
Sunscreens are intended to protect your skin from the sun’s harmful ultraviolet radiation, but certain chemical UV filters found in popular brands can also harm human health. Research has shown that oxybenzone, octocrylene, homosalate, avobenzone, retinyl palmitate, and octisalate are not only absorbed into the bloodstream but can also disrupt hormonal balance, damage DNA, and increase the risk of certain cancers. While the European Union has banned or restricted several of these ingredients, the United States still allows them in high concentrations, putting consumers at risk. In this blog, you will notice how these dangerous chemicals individually dont offer full spectrum UVA and UVB protection. That’s why there’s always a combination of multiple chemicals in common sunscreens to offer complete sun protection, amplifying the toxicity and overall danger. However, there is a single ingredient that offers full spectrum sun protection without the carcinogenic side effects, and that’s zinc oxide. It makes you question the ethicasy of these sunscreen companies when they synthesize these chemicals instead of using a simpler, cleaner alternative, like zinc oxide
Oxybenzone, also known as benzophenone-3, is a UVB and short-wave UVA filter that penetrates the skin easily and has been detected in urine, blood plasma, and breast milk. This chemical acts as a potent endocrine disruptor, mimicking estrogen and interfering with testosterone production. Studies have linked oxybenzone exposure to reduced sperm counts, altered birth weights, and the proliferation of breast cancer cells. When exposed to sunlight, oxybenzone can create harmful molecules called “free radicals” that can damage your skin cells, proteins, and DNA—kind of like rust slowly damaging metal. This damage can mess with how your skin repairs itself and might increase the chance of cancer. Its presence in the human body after sunscreen use is well-documented, yet it is still widely available in American products despite being restricted in the EU and banned in certain regions like Hawaii and Palau.
Octocrylene, another common sunscreen ingredient, is used for its UVB and short UVA protection and its ability to stabilize avobenzone. That’s right - sunscreen companies have to use more toxic chemicals just to stabilize the other toxic chemicals they are putting in sunscreens. Over time and under heat exposure, octocrylene degrades into benzophenone, a known human carcinogen that damages DNA and increases oxidative stress within cells. This breakdown product is particularly concerning because benzophenone is also a skin sensitizer and can cause chronic skin irritation. However, when it heats up or is exposed to sunlight, it can break down into another chemical called benzophenone, which is known to cause mutations in DNA. This means it can cause changes in your cells that might lead to cancer. It also makes your skin more sensitive to sunlight damage by producing more of those harmful free radicals we talked about. Several sunscreen products were recalled in 2021 after benzophenone contamination was found at unsafe levels, yet octocrylene remains a staple in U.S. formulations.
Homosalate is only good for UVB protection and is bioaccumulative, meaning it builds up in the body over time, particularly in fatty tissues, primarily because it’s so oily. This chemical disrupts the endocrine system by interfering with estrogen, androgen, and progesterone activity and has been linked to thyroid hormone imbalance and reproductive toxicity. When exposed to sunlight, homosalate breaks down into other chemicals that can hurt the energy factories inside your cells (called mitochondria). Over time, this can cause problems like hormone imbalances and even speed up skin aging. While the European Union limits its concentration to 0.5 percent due to safety concerns, the U.S. allows up to 15 percent in over-the-counter sunscreens.
Avobenzone is the most common UVA filter used in chemical sunscreens, but it is chemically unstable under UV exposure, breaking down into reactive compounds that can damage skin cells and DNA. You read that right - the most common chemical used in sunscreen is chemically unstable in sunlight, not to mention it breaks down into smaller chemicals that can damage your skin cells and DNA. Also, it only blocks one form of UV rays. This instability increases oxidative stress on the skin, accelerating the visible signs of aging and potentially increasing cancer risk. Avobenzone is almost always paired with octocrylene to improve stability, but this combination introduces the risk of benzophenone contamination, compounding the safety concerns. Moreover, when avobenzone is mixed with octocrylene, which is common, it formulates into benzophenone, which creates free radicals that damage cells and increase inflammation and risk of skin cancer.
Retinyl palmitate, a form of vitamin A palmitate and is added to some sunscreens to keep skin healthy. However, on sun-exposed skin, it undergoes photodegradation, producing free radicals that damage skin cells and accelerate the development of tumors and lesions, meaning it can make skin damage worse instead of better. Research from the U.S. National Toxicology Program has shown that retinyl palmitate can speed up the formation of skin cancers when applied before UV exposure.
Octisalate, or ethylhexyl salicylate, is used to enhance water resistance and stabilize SPF formulas. While considered less potent than other chemical filters, it can cause allergic skin reactions and, like the others, penetrate the skin and enter the bloodstream. Octisalate acts as a weak endocrine disruptor, with potential to disturb thyroid hormone regulation, and can remain in the body for days after use, leading to ongoing exposure with daily application.
All of these chemicals share a concerning characteristic: they are small, lipophilic molecules that easily cross the skin barrier. Once in the bloodstream, they can travel to hormone-sensitive organs, cross the placental barrier to reach developing fetuses, and appear in breast milk. The U.S. Food and Drug Administration has acknowledged that the levels of these sunscreen chemicals found in the blood exceed the threshold at which additional safety testing is required, yet regulatory changes have been slow to follow.
The European Union takes a stricter approach by applying the precautionary principle, meaning it restricts or bans ingredients when credible evidence of harm emerges. The United States, in contrast, has a slower and less responsive review process, allowing ingredients banned abroad to remain in circulation for decades. This regulatory gap means that American consumers are often unknowingly exposed to chemicals with established health risks.
The safest alternative to these problematic chemical UV filters is non-nano zinc oxide. This mineral-based sunscreen works by physically reflecting and scattering UV rays rather than absorbing them into the skin, and remains on the skin’s surface without entering the bloodstream. Zinc oxide provides broad-spectrum protection, is photostable, and is free from the hormone disruption and carcinogenic risks associated with chemical filters. At Shaw Naturals, we exclusively use non-nano, uncoated zinc oxide to deliver safe, effective, and reef-friendly sun protection.
Ultimately, the presence of oxybenzone, octocrylene, homosalate, avobenzone, retinyl palmitate, and octisalate in sunscreens is not just an environmental concern—it is a direct human health issue. By choosing mineral-based sunscreens, you can protect your skin from harmful UV rays without exposing your body to chemicals that may do more harm than good.