A worrying trend of girls starting puberty earlier is raising questions about whether chemical exposures play a role. Now a new study suggests a link between certain chemicals in everyday products like fragrances and cleaners, and how they can disrupt the hormones in the brain involved in puberty.
The study, published this week in the peer-reviewed journal Endocrinology, tested over 10,000 environmental compounds on human brain cells to see if they affected the hormones that lead to puberty.
Puberty is controlled by a part of the brain called the hypothalamus, which regulates hormones. This gland releases hormones that cause physical changes like breast growth and menstruation in girls.
The study was led by researchers at the National Institutes of Health and Northwestern University.
The age when girls enter puberty has gotten earlier and earlier in past decades, though the reasons are unclear. The trend has been more pronounced among girls in communities of color and those in families living on lower incomes.
Factors like genetics and diet play a role, but research increasingly suggests environmental exposures also have a part. Products people use every day, and the food and drink they consume, are all potential sources of exposure.
The authors identified several chemicals that may prompt key receptors involved in puberty, which in turn can cause the hypothalamus to jumpstart the reproductive system, leading to early puberty.
Early puberty is associated with a higher risk of long-term health problems, such as decreased fertility, diabetes, cardiovascular disease and breast cancer.
Toxic chemical exposures
One of the compounds the study identified as potentially leading to premature puberty was musk ambrette, a fragrance ingredient used in cheap and counterfeit perfumes, air fresheners and personal care products.
When tested on animal cells, musk ambrette triggered the release of one of the hormones that sparks puberty and leads to the production of sex hormones like estrogen and testosterone.
The study focused on chemicals that may trigger early puberty in girls. Studies have noted that girls are starting puberty younger, which could be because girls are more sensitive to hormones like estrogen, which plays a key role in their growth and development.
The European Union and Canada have banned musk ambrette for use in cosmetics, and the International Fragrance Association prohibits its use in fragrance. But it may still be found in products with undisclosed “fragrances” on the ingredient label, as well as imported products or those sold in secondhand or dollar stores.
Musk ambrette is not used as an ingredient outside of fragrances, based on a review of our Skin Deep® database of more than 100,000 personal care products. People also may be exposed to musk ambrette in contaminated food and liquids.
The study also identified a second group of chemicals called cholinergic agonists, which control muscle movement and memory. Researchers found these chemicals can activate a receptor that mimics the body's natural hormone involved in starting puberty, leading puberty to start earlier than normal.
Cholinergic agonists are mostly found in prescription drugs, but the study’s authors said chemicals with a similar structure deserve further review.
Hormone-disrupting chemicals
Other studies have also identified associations between chemical exposures and early menstruation. including endocrine disrupting chemicals, which can alter the normal function of hormones. But more research is needed on the possible sources of exposure.
Early puberty has been associated with chemicals such as the toxic “forever chemicals” known as PFAS, phthalates and phenols, among others.
Reducing your exposure
It’s impossible to avoid exposure to harmful chemicals in daily life completely, because they’re found not just in personal care and household products but also in drinking water and food. But there are steps that can help reduce exposure, including:
- Choose safer products: Use our Healthy Living app, Skin Deep database, and Guide to Healthy Cleaning to identify products that score well. Look for items that bear the EWG Verified® mark, as these products have been reviewed by our scientists and meet our rigorous standards for health and transparency.
- Avoid undisclosed fragrance. Watch for this term on product labels – it may indicate the presence of musk ambrette. Instead choose products that disclose all their fragrance ingredients, or look for our EWG Verified mark.
- Review EWG’s page on toxic chemicals for more information about various substances, and consult our consumer guides to help reduce exposures to chemicals.
