Xenoestrogens – what they are and why we need to avoid them

The impact of oestrogen-mimicking ingredients on our health. Words by Terri Vinson, founder and cosmetic chemist at Synergie Skin.

There is mounting concern over the use of xenoestrogens in our environment and the long-term effects on natural hormone balance. Xenoestrogens are simply hormone disruptors. They are foreign oestrogen ‘mimickers’ that increase the oestrogen load in our bodies and can disrupt hormone activity.

Oestrogen is a natural hormone produced by men and women and is constantly regulated by the body, signalling different types of cells and organs to perform specific functions. Studies suggest that xenoestrogens, or synthetic oestrogens, enter our bloodstream and cells and ‘fool’ our bodies into accepting the chemicals as our natural biological oestrogen. This can potentially block or bind the natural oestrogen hormone receptors.

When xenoestrogens enter the body, they increase the total amount of circulating oestrogen resulting in a phenomenon called ‘oestrogen dominance’. Medical research has linked xenoestrogens with a range of serious human health concerns and can influence the following functions: immunity; bone development; blood clotting; reproduction; reproductive development in babies and adolescents of both sexes; development of organs such as the uterus and the breasts.

Once they enter the bloodstream, xenoestrogens are not biodegradable and are readily stored in our fat cells. These hormone disruptors can be found in more than 50,000 commonly used chemicals and are present in soil, water, air, store purchased foods, personal care and household products.

Xenoestrogens in personal care products

Paraben preservatives 

(Examples include methyl paraben, ethyl paraben and propylparaben.) Numerous studies have linked paraben preservatives to oestrogen-mimicking activity on living cells. There are now many more preservative choices available to formulators who wish to avoid adding paraben preservatives to their products.


(Examples include dibutyl phthalate, dimethyl phthalate and diethyl phthalate.) Phthalates are solvents and fragrance fixatives to make the scent last longer. They are also used in hairsprays to promote flexibility and movement in hair.

Phthalates are often not listed on labels as manufacturers are only required to list: ‘fragrance’ or ‘parfum’, and not the individual constituents of a fragrance.

Dibutyl phthalate is currently banned in the EU. There have been findings that excess exposure to phthalates during pregnancy is linked to male infertility and ADHD in children. Synergie does not use phthalates or artificial fragrances and is only formulated with essential oils.

Soy-based products

Soy is an oestrogenic ingredient which can influence hormonal levels. Whilst soy is not dangerous to the unborn child, if you are prone to melasma (large dark pigmented patches on the face), soy products (including lecithin and textured vegetable protein) may worsen this condition during pregnancy.

Chemical sunscreens 

In addition to its effects on humans as hormone disruptors, the use of chemical sunscreens (aka ‘organic sunscreens’) by swimmers on our beaches has been linked directly with environmental issues and the sterility and the death of our beautiful coral reefs.

Whilst any sunscreen is better than none, opt for natural mineral sun protection with zinc oxide giving broad spectrum protection. It is wise to avoid the following chemical-absorbing sunscreen ingredients that have xenoestrogen activity: Oxybenzone; Benzophenone; Homosalate; 4-methyl-benzylidene camphor; and Octalmethoxycinnamate.

A recent study looked at a population of women in Iran. The findings indicate direct correlation with xenoestrogen exposure and the incidence of pre and postmenopausal breast cancer. Results showed that the onset of breast cancer in Iranian women tends to be about a decade earlier compared to Western and North American societies. It was found that Iranian women generally have higher levels of exposure to plastics, petroleum refining and other environmental xenoestrogens. Furthermore, the closer they lived to facilities and refineries that produced these xenoestrogens, the higher and earlier the incidence of breast cancer.

The skin is our largest and most highly absorbent organ. It is highly vulnerable to the impact of our external environment and this includes personal care products. The average woman absorbs over two kilograms per year of chemicals from skincare and cosmetic products and many of these ingredients contain hormone disruptors that have a questionable impact on the human body.

This article is not intended to incite fear and not every individual will be directly impacted by oestrogen mimickers. I do believe, however, that long term and repeated exposure to xenoestrogens should be avoided and consumers must be aware of safer options. When given the choice, I recommend choosing the ‘clean science’ in skincare and avoiding questionable ingredients such as hormonal disruptors which may negatively impact our cells, tissues and organs.

Excess oestrogen is linked to such conditions as

  • Breast, prostate and testicular cancer
  • Obesity
  • Male and female infertility
  • Endometriosis
  • Early onset puberty
  • Miscarriage
  • Compromised neurological systems
  • Diabetes
  • Aggravated menopausal symptoms