Is Your Sunscreen Messing With Your Hormones? What the Latest Research Says

by Tess Cameron December 31, 2025

We’ve all heard the golden rule of skincare: wear sunscreen every day. It is our primary defense against skin cancer and premature aging. However, in recent years, a growing body of research has turned the spotlight on the active ingredients in chemical sunscreens, raising questions about their safety—specifically their potential to act as endocrine disruptors.

If you’ve been seeing headlines about "hormone-disrupting" sunscreens, here is a deep dive into what the science actually says as of 2025.

The Problem: Systemic Absorption

For a long time, it was assumed that sunscreen stayed on the surface of the skin. However, landmark studies by the FDA have changed that narrative.

Recent clinical trials published in JAMA (Journal of the American Medical Association) found that several common chemical filters—including oxybenzone, avobenzone, octocrylene, and homosalate—are absorbed into the human bloodstream after just a single application. Even more concerning, these levels remained significantly higher than the FDA’s safety threshold for weeks after use stopped.

The "Big Three" Ingredients of Concern

While research is ongoing, three specific ingredients frequently appear in studies related to hormonal interference:

1. Oxybenzone (Benzophenone-3)

Oxybenzone is the most widely studied chemical filter. Research indicates it can mimic estrogen in the body and has been linked to:

Lower testosterone levels in adolescent males.
Altered thyroid hormones in pregnant women.
Decreased sperm quality and motility in men.
Environmental impact: It is notorious for contributing to coral bleaching, leading to bans in places like Hawaii and Thailand.

2. Octinoxate (Octyl methoxycinnamate)

Studies on animals have shown that octinoxate can interfere with the signaling of progesterone and androgen. In humans, higher urinary concentrations of octinoxate have been associated with delayed puberty in boys.

3. Homosalate

This ingredient is used to help sunscreens penetrate the skin. The European Commission recently moved to limit its concentration to 0.5% (down from 10-15% commonly found in the U.S.) due to concerns that it disrupts estrogen, androgen, and progesterone levels.

Cumulative Effects and "Mixed Exposure"

A significant review of research from 2014–2024 highlights that we rarely use just one chemical. Most sunscreens use a cocktail of filters. This "mixed exposure" can have cumulative effects on the endocrine system that are harder to track than single-ingredient tests.

Important Note: While these associations exist, many dermatologists point out that "association" does not always mean "causation." Most human studies show potential risks, but we lack long-term, multi-decade clinical trials to definitively prove these chemicals cause specific diseases in humans.

Should You Stop Using Sunscreen?

Absolutely not. The risks of UV radiation melanoma, squamous cell carcinoma, and DNA damage are well-proven and life-threatening.

If you are concerned about hormone disruption, you don't have to skip protection; you just need to switch your formula.

The Alternative: Mineral Sunscreens

Mineral (or physical) sunscreens use Zinc Oxide or Titanium Dioxide.

How they work: Unlike chemical filters that absorb into the skin, minerals sit on top of the skin and primarily reflect/scatter UV rays.
Safety: The FDA currently classifies Zinc Oxide and Titanium Dioxide as GRASE (Generally Recognized as Safe and Effective). They are not absorbed into the bloodstream and do not pose a risk of hormone disruption.

Tips for Your Next Purchase

Check the Active Ingredients: Look for "Zinc Oxide" or "Titanium Dioxide" as the only active ingredients.
Avoid Sprays (if possible): If using a mineral spray, be careful not to inhale it, as the lungs can struggle to clear mineral nanoparticles.
Look for "Non-Nano": This ensures the mineral particles are large enough that they cannot be absorbed through the skin or pores.

Citations & Further Reading

FDA Center for Drug Evaluation and Research (2020). "Effect of Sunscreen Application on Plasma Concentration of Sunscreen Active Ingredients." JAMA.
PubMed (2024). "Endocrine and Reproductive Health Considerations of Sunscreen UV Filters: A Comprehensive Review 2014-2024."
Environmental Working Group (EWG). "2025 Guide to Sunscreens: The Trouble with Ingredient Safety."
European Commission Scientific Committee on Consumer Safety (SCCS). "Opinion on Homosalate."