Chemical Exposures and Testosterone

What causes low testosterone? The answer is, lots of things influence our testosterone levels. Aging is the biggest reason why testosterone declines. Every year after age 30, levels drop around 1% per year. This may not sound like much, but by middle age, many men feel the effects of lower testosterone levels.

Levels of testosterone have dropped around the world for the past few decades leading to concern and confusion about the causes. Our environment is full of endocrine disruptors and estrogen mimickers in plastics, foods, and personal care products. These products certainly disturb proper hormonal function and may be responsible for the decline in global testosterone.


Phthalates are chemicals added to plastics to make the softer or more flexible (like in shower curtains, vinyl coverings, or food packaging). Oily or fatty foods exposed to phthalates in packaging (like commercial plastic wrap) or foods heated in these packaging materials seem to be at increased risk of leaching. Phthalates are also often added to personal care products like moisturizer or added as “fragrance.” These chemicals are also present in pesticides, medical equipment, insect repellent, and plastic toys.

Phthalates are known hormone disruptors. One study found that 90% of participants had measurable levels of phthalates in their blood. Participants with the highest levels of phthalates had lower testosterone and the association was most noticeable in boys, ages 6-12, and men, ages 40-60. Phthalates are everywhere and we live in a plastic-filled world, so it is impossible to completely avoid these chemicals. But you can reduce your exposure by limiting processed and packaged foods (especially those packaged in plastic labeled as PVC or marked with the number 3 in the triangle of arrows), not microwaving food in plastic containers or wraps, and choosing personal care products using the Environmental Working Group‘s Healthy Living app.

Bisphenol A

Bisphenol A (BPA), another chemical commonly found in plastic products, may negatively impact testosterone and sperm levels. BPA may interact with the cells that produce testosterone in the testicles, as well as interacting with the pituitary gland, the “master gland” of the endocrine system. Increased BPA levels have been associated with lower testosterone levels in adolescent boys and elevated testosterone levels in adolescent girls. Additionally, BPA has been shown to reduce sperm count and quality animal models.

BPA can be found in:

  • Older plastic water bottles (made before 2012)

  • Food containers

  • Thermal receipt paper

  • Aluminum can linings

But good news millenials, La Croix is now BPA free.

Reducing exposure to BPA by choosing products that are BPA free or better yet, are not plastic is a way to keep your hormone levels healthy. I have used a Nalgene bottle since high school but recently switched to a metal bottle from Kleen Kanteen to help reduce my exposure to plastic. Taking small steps like this can have a big impact on your overall exposure.


Triclosan used to be everywhere. It was the antibacterial agent in antibacterial soaps (which you should not use, btw). The FDA made it illegal in soaps in 2016 (good), but it’s still found in toothpastes and mouthwashes (not good).

In animal studies, exposure to triclosan has been associated with lower sex hormone levels. Additionally, this chemical has been shown to interfere with proper thyroid function in animal and human studies. Human studies also suggest an association between triclosan exposure and increased risk of asthma and allergies.

Recent studies in adult males also found that higher triclosan exposure was associated with decreased semen quality and decreased sperm quality. More research needs to be done to determine if triclosan is associated with decreased testosterone levels in humans. To avoid this chemical, make sure you are reading the ingredients on your toothpaste or mouthwash and choosing products that do not contain triclosan. Your little swimmers will thank you.


Exposure to pesticides has been linked to decreased serum testosterone levels in men. One study of Native American men found that higher levels of chlorinated pesticides were associated with lower levels of testosterone. Another small study in Thailand found similar results. Chlorinated pesticides have also been associated with disruption of proper thyroid and female hormonal function.

Pesticide exposure is unavoidable in our world. DDT, a well known chlorinated pesticide, has not been used in the US for decades but continues to hang out in the food system. We are also exposed to pesticides every day when we eat non-organic produce.

Everyone cannot afford to eat a 100% organic diet. I understand that because I can’t afford it, either. I choose to buy organic for the most pesticide heavy products and choose conventional for those that have less pesticide exposure. The Environmental Working Group yearly Dirty Dozen and Clean Fifteen lists are a great place to start. Check it out!

It’s important to remember that correlation does not equal causation. The associations between these chemicals and lower testosterone do not necessarily mean that the chemicals are causing the decline. There is no research on the combination of these products and how those affect hormone functioning.

For me, it is important to avoid potentially harmful substances whenever possible. I use the Environmental Working Group website and app all the time to help me make informed choices about which products I use for cleaning and personal care.

Learn more about testosterone and men’s health at