Shedding light on sun protection, sunscreen and hormones

Sunscreen and hormones

With summer around the corner, warmer weather equals more time outdoors. And that means it’s the perfect time to evaluate what your skin needs and what sun protection you’re comfortable with. Before you head outside, here’s what to consider when it comes to sun protection, ingredients in your sunscreen, and your hormones.

Understanding the different types of UV light

Sun damage can happen in as few as 15 minutes—hardly any time at all. There are three different kinds of UV light, but only two we have to be concerned with: UVA and UVB. (UVC cannot get through the atmosphere.)

UVB rays don’t penetrate the deeper layers of our skin, but they can cause delayed tanning and burning. UVA reaches the deeper layers of the skin. It leads to premature skin aging, like wrinkles, and can potentially cause skin cancer.

The importance of sun protection

With nearly 10,000 individuals diagnosed with skin cancer daily in the U.S. alone, sun protection is important year-round. It helps prevent short- and long-term sun damage and skin cancer.

A common myth is that people of color don’t need to be as concerned with sun care as fairer tones. However, absolutely everyone needs a combined approach to sun protection, and the more natural it is, the better. Also, everyone needs annual skin exams—regardless of race or ethnicity, or how much melanin your skin naturally has.

How to protect yourself from the sun & why a multifaceted approach to sun protection is best for your hormones

Adequate sun protection isn’t any one thing. It should be a combination of shade, protective clothing, and, when needed, sunscreen. In my opinion, shade is the best natural sun protection there is. Combine shade with:


Any fabric will help reduce your sun exposure, especially if it’s tightly woven. T-shirts only offer an SPF of about 5, and when they get wet in the water, that protection becomes even less.

Many clothes designed for the outdoors advertise an ultraviolet protection factor, or UPF. UPF is a number that describes how well the clothing protects from UVA and UVB light. For example, a UPF of 40­–50+ blocks about 98% of UV radiation.


Wearing shades protects the eyes from UV radiation and reduces cataracts risk. Another benefit of sunglasses is the extra protection for the skin around your eyes, which is especially thin and delicate.


From a naturopathic perspective, sunscreen isn’t my only resort for sun protection. Many conventional sunscreens have been linked to tissue damage, hormone disruption, and allergic reactions. Using a combined approach to sun protection can minimize these effects.

Chemicals in sunscreens and how they can possibly affect hormones

Recently, the FDA evaluated whether several common active sunscreen ingredients in conventional sunscreens could be absorbed through the skin and into the bloodstream. Results showed that it’s possible, and the FDA has decided to investigate these chemicals for more information. Three of these chemicals are oxybenzone, octinoxate, and homosalate.


Oxybenzone exists in many sun products, including makeup and other cosmetics that promise UV protection. It’s great at doing its job of filtering rays, but your skin absorbs it in significant quantities and it may bioaccumulate in your tissue. Lab testing has found it in blood and breast milk.

Oxybenzone may have reproductive toxicity. Chemicals in the benzophenone class can mimic estrogen in your body and activate both ERα and ERβ estrogen receptors—influencing cell proliferation and growth.

Benzophenones can also affect androgen hormones, like testosterone, which are important to both a woman’s and man’s vitality, fertility, and overall health. By interfering with androgen receptors (AR), oxybenzone and other chemicals like it may prevent your body from being able to fully utilize its androgen hormones.


Octinoxate has a long history of being used in cosmetics and products with sun protection. It filters UV-B rays and is easily absorbed through the skin.

Like oxybenzone, octinoxate can act like estrogen in the body. It may affect both female and male fertility, altering menstrual cycles and lowering sperm count in men. While there’s currently no evidence octinoxate alters thyroid-stimulating hormone, it does harm thyroid function, lowering levels of the thyroid hormone thyroxine (T4).


Homosalate helps absorb UVB rays and enhances your skin’s absorption of the sunscreen. (And all of the chemicals in it.) It’s also linked to endocrine and hormone disruption.

Other sunscreen ingredients

Many other common sunscreen ingredients have ties to hormonal changes, allergies, and immunotoxicity and interfere with optimal health. Some of these chemicals include parabens, BHT, and fragrances.

Tips for choosing a safer sunscreen

If you’re looking for a sunscreen to combine with other methods of sun protection, I suggest considering:

Avoiding sprays

Sunscreen sprays have become highly popular thanks to their ease of use. But sprays do come with an inhalation risk—and they might also have some other ingredients you weren’t expecting or don’t want. For example, it’s not uncommon to see insect repellant included in sprays.

Evaluating all chemicals in conventional sunscreens

Beyond the ones mentioned earlier, other chemicals make their way into many sunscreen products. Their effects are not negligible. Homosalate, benzyl alcohol, styrene, and fragrances all become absorbed by the skin and impact your body.

Looking for zinc oxide

Mineral sunscreens offer sun protection that are less disruptive to hormone balance. Mineral sunscreens usually contain zinc oxide and/or titanium dioxide. Even though zinc oxide and titanium oxide can penetrate the skin to a minimal degree, the nanoparticles don’t appear to make their way through deeper layers of the skin and into the bloodstream. Instead, they sit on the surface and act as a physical barrier against the sun’s rays.

Going for an SPF of 30–50 (but no higher)

When looking for a sunscreen, choose an SPF of 30 to 50. Avoid SPFs any higher than that range. Sunscreen with an SPF of 30­–50 gives enough sunburn protection for everyone. A well-applied SPF 50 sunscreen blocks about 98% of the sun’s rays. SPF 100 blocks 99% of rays—only a 1% difference. Plus, high-SPF sunscreens have greater concentrations of chemicals that filter the sun. That could lead to more tissue damage, hormone disruption, and more severe allergic reactions.

Paying attention to UVA vs. UVB rays

Also, remember this: the components resulting in SPF are geared toward blocking UVB rays but not UVA. UVA rays penetrate the skin and can ultimately suppress the immune system in some people, causing free radicals to form. Broad-spectrum sunscreens can help, but an overall approach to sun protection that includes shade and clothing is the best thing you can do for your body.

The right sun protection is essential to optimal health

As a naturopathic doctor, my focus for health aligns traditional medicine with a whole-person and natural approach. By looking for root causes of hormone and other dysfunctions, we can restore optimal health. While sun protection is absolutely essential to caring for the skin, using a combined approach allows us to reduce the number of chemicals being absorbed through the skin.

Nicole Lewis, ND