Why are endocrine disruptors bad for your health and skin?
Endocrine Disruptors (EDCs) are at the heart of a major scientific and societal awakening. For the past twenty years, research has fully measured their impact on human health—and on the skin. At Skin Diligent, this reality is fundamental to our approach.
What Endocrine Disruptors Are
According to The Endocrine Society, endocrine disruptors are chemicals that can interfere with our multiple endocrine (hormonal) systems, including those involved in: fetal development, immunity, fertility, metabolism, weight regulation, and brain development.
What particularly concerns researchers today: their effects do not stop at a single generation: some exposures can leave a biological imprint transmissible to children—or even grandchildren. Certain periods of life are particularly sensitive: pregnancy and puberty, where the body is more sensitive to hormones and disruptive substances.
The Skin is Not an Impermeable Barrier
If a skincare product only stayed on the outer layer of the skin, endocrine disruptors in the formulas would not be a problem. The reality is different.
When you take a bath, your body does not double in size—so the skin is waterproof. But it is selectively permeable: certain ingredients pass through the skin due to their minuscule size, low molecular weight, or because they are carried by delivery systems. If you have ever used a nicotine patch or a hormonal patch, you know that active molecules can be administered through the skin.
If the active ingredients of an anti-aging cream reach the dermis, the toxins present in that same formula can unfortunately reach it too.
Endocrine Disruptors and Epigenetics: A Direct Link
EDCs don't just disrupt our hormones. They also interfere with the epigenome—the control layer that determines the activation or deactivation of our genes.
Research shows that EDCs can alter this control system through mechanisms such as changes in DNA methylation, histone structure, and microRNAs. These mechanisms do not change the DNA itself, but change how cells function over time—sometimes permanently.
In the context of breast cancer, this data is particularly monitored. Studies suggest that chronic exposure to substances like BPA, phthalates, parabens, dioxins, and heavy metals can leave epigenetic imprints on breast tissue, increasing vulnerability to certain pathologies. Scientific evidence clearly points to a link between chronic exposure and increased risk.
What Regulation Says—and Its Limits
In Europe, cosmetic standards are among the strictest in the world. But one point remains problematic: the official list of endocrine disruptors is very short, and the process to include a suspected ingredient often takes a decade or more. The lobbying power of the chemical industry is considerable.
To date, the EU has confirmed only 25 ingredients as endocrine disruptors. Hundreds of other substances (mostly synthetic) are on lists of suspected substances—without yet being regulated. Moreover, a banned ingredient can continue to be sold for up to 7 years after its ban, until stocks are depleted.
Skincare products simply need to avoid ingredients on official lists—but no testing is required to prove the absence of endocrine disruption in the final formula.
The Cocktail Effect: Why Avoiding Listed Ingredients Isn't Enough
In chemistry, the cocktail effect refers to the result of a mixture of ingredients. An ingredient that is perfectly harmless in isolation can become an endocrine disruptor when combined with other molecules in a finished formula.
Thus, the absence of "listed" ingredients does not guarantee a truly safe product. Only a test on the complete final formula can certify the absence of disruptive activity.
We know, thanks to our own tests, that there are natural ingredients that do not appear on any official list but have nevertheless shown endocrine disrupting activity once integrated into a formula.
How to Reduce Your Daily Toxic Load
It is impossible to eliminate all exposure to toxins in our modern lives. But it is possible to reduce your toxic load. Here are the main sources of EDCs to watch out for:
- Plastics (baby bottles, water bottles) — never heat food in plastic containers
- Flame retardant coatings on children's toys, clothes, and bedding
- Stain-resistant coatings on furniture
- Paints with high levels of volatile organic compounds (VOCs)
- Skincare and hygiene products (untested cosmetics)
- Synthetic petroleum-based fabrics in prolonged contact with the skin
- Household cleaning and laundry products
- Paraffin-based indoor candles
The Skin Diligent Commitment: Testing Finished Formulas, Not Just Ingredients
Skin Diligent is the first brand to systematically test all its finished formulas for estrogenic endocrine disruption—via the OEDT test, an innovative in vitro test on living cells, developed jointly by academia and the French industry.
Our products are therefore suitable for pregnant or breastfeeding women, women who have had breast cancer, and anyone wishing to reduce their toxic load. (The CEL™ Retinal Serum is an exception, like any product containing retinoids, which are not recommended during pregnancy).
Tule Park, Co-founder of Skin Diligent