Teen Girls Cut Hormone-Disrupting Chemicals in Just Three Days by Switching Products

The study Reducing Phthalate, Paraben, and Phenol Exposure from Personal Care Products in Adolescent Girls published in the peer reviewed journal Environmental Health Perspectives set out to see if swapping body care containing common endocrine disrupting toxins with body care that is free from toxins would make a difference to the body’s toxic load in teenage girls. This is what they found and how they measured it. 

Why is this study important?

Endocrine disruptors are very universal and difficult to avoid. They are substances that mimic, block or interfere with the body’s natural hormones. They are found in skincare, cosmetics, fragrances, sunscreens, food and beverage packaging (the reason why we see BPA packaging), household cleaning products, non-stick cookware (Teflon) and even some carpets and textiles.

In terms of skincare and body care, the most prominent culprits include phthalates, parabens, triclosan and benzophenone-3 (BP-3, or oxybenzone in sunscreen). We now commonly see labels specifically excluding these.

Scientific studies in labs demonstrate that these chemicals act like weak oestrogens or block androgens. They are officially classed as endocrine disrupters and according to a national study in the United States, they are present in the urine of more than 90% of people. Like we said, difficult to avoid.

This study was particularly interested in testing teenage girls, predominantly because of the level of exposure teenager girls have to personal care products every day. One study cited girls are using on average 12 products by the time they are 17. We could also suggest that monitoring hormone disruption at such a pivotal time in the hormonal development of girls and boys as teens is highly important in a world where exposure is likely.

Labels such as “Phthalate-free” and “paraben-free” are becoming common, but this study wanted to see just how much difference it would make to swap from products that contain these, to products that are free from them. The researchers set out to find out if we see a decrease in the levels of these chemicals present in the body.

What they measured, and how

The researchers enrolled 100 Latina American girls aged 14 to 18 in Salinas, California, a largely low-income farming community. Fifteen local high school students helped design and run the study. They helped choose the products, recruited participants and collected the data.

At the start of the trial each girl gave a urine sample. She was also given replacement products with labels that said they did not contain phthalates, parabens, triclosan or BP-3. The kit covered shampoo, conditioner, body wash, lotion, soap and deodorant, plus four makeup or sunscreen items of her choice. Phthalates don’t have to appear on ingredient lists, so the team avoided anything with “fragrance” unless it was specifically labelled phthalate-free. The products weren’t lab-tested. The point was to use only the information an ordinary shopper has.

The girls used only these products for three days. Then they gave a second urine sample at the same time of day as the first, so normal daily ups and downs wouldn’t skew the comparison. A state public health lab measured nine target chemicals using mass spectrometry. A three-day window works because these compounds leave the body within one to two days.

What the researchers found: chemicals were reduced

On average, levels fell noticeably:

• Methyl paraben: down 44%
• Propyl paraben: down 45%
• BP-3 (oxybenzone): down 36%. Among girls who had been wearing sunscreen, it fell 52%.
• Triclosan: down 36%. Among girls who had been using a toothpaste containing triclosan, it fell 70%.
• Mono-ethyl phthalate (from diethyl phthalate, which is used in fragrance): down 27%

Two other phthalates barely changed. They also come from food, house dust and household products, and one clears from the body more slowly. Ethyl and butyl parabens unexpectedly went up, but they started at low levels and were detected in only about half the girls. Because the replacement products weren’t tested, the researchers couldn’t say where these came from. As a check, chemicals that mostly come from plastics rather than cosmetics, such as BPA, didn’t change.

All these chemicals are consider endocrine disrupters which are leading researchers to see how much they are impacting rising rates of infertility, reproductive health issues, thyroid issues, brain development issues and autoimmune disorders. 

Changing to clean products can reduce chemical load in the body

Levels fell but didn’t disappear. More than 90% of the girls still had detectable amounts afterwards, and some girls’ levels rose. Possible reasons include the short three-day window, other sources in the home, and imperfect compliance: 35% used other soap at least once. There was also no control group, and everyone in the study came from one community.

Swapping products can make a difference

This was the first study to show that a simple step anyone can take, reading labels and choosing products marketed as free of these chemicals, can measurably lower exposure within days. The authors also noted a practical problem: low-chemical makeup was hard to find and often expensive, especially in low-income areas. Afterwards, 71% of the girls said they planned to buy products free of these chemicals.

We wonder if they continued to measure over a longer period if we would see accumulative amounts in urine decrease even more. We also wonder if other fluids were tested such as blood, we would see the chemicals showing up in different ways within the body. Blood is excellent for identifying acute, recent exposure. It shows what is currently circulating in the system before the liver or kidneys filter it out. It is also the primary choice for testing chemicals that bind to lipids or red blood cells. Whereas urine sampling measures only water-soluble chemicals and metabolites (the breakdown products of toxins) that the body is actively trying to eliminate.

It would be interesting to know why 29 %of the participants would not change their products after the study. If this was due to performance of the products, perception over packaging, branding and effectiveness or cost concerns. Clean and natural products mostly do sit in a higher price bracket, many non-chemical ingredients do have a higher raw cost. We hope to see more options available to make clean products accessible to a wider range of people.

Harley et al. (2016), “Reducing Phthalate, Paraben, and Phenol Exposure from Personal Care Products in Adolescent Girls,” Environmental Health Perspectives 124(10):1600–1607.