When you think of sunscreen, it’s logical to assume that something that protects you from skin cancer would be safe to use, especially since the FDA regulates and considers sunscreen ingredients as drugs. But a closer look at the typical ingredients that go into sunscreen can reveal a slew of toxic villain ingredients with the potential to have adverse effects on your health.

UV protection from comes in two forms, chemical filters, each of which absorb UVA and UVB rays to varying degrees and are referred to as ‘sunscreens’. ‘Sunblocks’ on the other hand are mineral formulations that physically block UV Rays from your skin. The two mineral sunscreen ingredients, zinc and titanium dioxide are considered the safest way to protect your skin as long as they are in non-nano size form or aerosolized or sprayed and inhaled.

Of the chemical sunscreen filters currently approved for use in the Untied States, several have been found to penetrate the skin and disrupt estrogen and progesterone hormone levels, alter thyroid activity and cause allergic reaction. The following list contains the most commonly found sunscreen ingredients to avoid that are chemical UV filters along with the basics of what you should know about them.

Octinoxate – The most widely used chemical UV filter, octinoxate blocks only UVB rays requiring it be combined with another filter for broad-spectrum protection. It is a penetration enhancer, which means it definitely absorbs into the body through the skin and helps other ingredients follow suit. Several studies show that this ingredient mimics the presence of estrogen (elevated levels of estrogen are linked to breast cancer) and can cause reproductive organ toxicity. While not banned in the EU, Canada, Japan or the U.S., research on the safety of this ingredient is ongoing

Oxybenzone – Though one of the most common UV filters, oxybenzone is not the strongest and is often paired with other filtering ingredients. Several studies show that this ingredient can be absorbed by the skin, stay in the body and mimic the presence of estrogen, which can be linked to breast cancer. It can also cause eczema and skin allergies and is on Spa Heroes’ list of toxic Villain Ingredients. Banned from use in Japan and Sweden. Permitted at limited levels in the rest of the EU.

Avobenzone – Also known as Parsol 1789, this commonly used chemical UV filter blocks the full range of UVA rays and is therefore considered broad spectrum. However, ironically, this chemical filter loses its filtering ability easily when exposed to light so it is almost always paired with other photo-stabilizing chemicals and often other UV filters to maintain its efficacy. While this appears to be a safer chemical UV filter, be sure to look out for other sunscreen ingredients to avoid alongside it that may be toxic. Banned from use in Japan.

Homosalate – Another commonly found chemical filter, homosalate blocks UVA rays and is often combined with with other chemical filters to offer higher UV protection. Since this ingredient was approved for use in the U.S. in 1978, several studies have been performed showing that this ingredient accumulates in the body and disrupts hormones. Environment Canada, Canada’s version of the EPA, has determined that they expect that this ingredient will be found to be toxic and harmful to health, but has yet to ban the ingredient. Banned from use in Japan.

As it stands, no new sunscreen ingredients (drugs) have been approved for use in the U.S. since 1999, there is some recent developments when it comes to the availability of new sunscreen technology. In November 2014, the Sunscreen Innovation Act was signed into law, requiring the FDA to review the safety of all new UV-filtering ingredients. This law was approved after frustration that new UV filtering ingredients commonly used overseas for over a decade were still not allowed in the US. While this law does not help reevaluate the already approved sunscreens and require them to be re-tested for safety, it does offer a path to exploring safer alternatives. We have yet to learn if these new alternatives are safer than what is currently approved and consumers will still need to check ingredient labels for any combination of harmful ingredients. But, don’t be surprised if you see news of new sunscreen ingredients in 2016 as this new law gives the FDA one year to review and approve or deny the backlog of ingredients up for review and requires that all future submissions be reviewed within 18 months.

Beauty Heroes features a curated collection of physical block sun screens in our Beauty Store.