What are xenohormones and should we be worried about them in cosmetics? This article talks about the alleged dangers of estrogen and other endocrine disruptors in beauty products.

What is the endocrine system?
The endocrine system is responsible for controlling biological processes such as metabolism, blood sugar levels, growth and function of the reproductive system, and the development of the many organs.

It has three parts:

  1. Glands are organs like the thyroid, testes and ovaries that secrete specific chemical substances called hormones.
  2. Hormones, which are chemicals that stimulate cells or tissues into action. For example, there’s estrogen, which regulates menstrual cycles.
  3. Cell receptors that pick up the signal from the hormones and trigger a response. Estrogens (for example estradiol) are a group of steroid compounds, named for their importance in the menstrual cycle and function as a primary female sex hormone.

The problem is that certain chemicals can mimic the effects of hormones and interfere with normal operation of the endocrine system.

Xenohormones and endocrine disruptors
Chemicals that can ‘fake out’ cell receptors are known as Xenohormones. These are a group of either naturally occurring or artificially created compounds with hormone-like properties.

The most commonly occurring xenohormones are xenoestrogens. (By the way, there are also xenohormones that mimic other hormones such as xenoandrogens and xenoprogesterones.)
Xenoestrogens are often referred to ‘environmental hormones’ or ‘EDC’ (Endocrine Disrupting Compounds).

EPA definition:
An EDC is “an exogenous agent that interferes with synthesis, secretion, transport, metabolism, binding action, or elimination of natural blood-borne hormones…”

So what are these EDCs?
They can be either synthetic or natural. Some synthetic examples include industrial solvents/lubricants and their byproducts [polychlorinated biphenyls (PCBs), polybrominated biphenyls (PBBs), dioxins, materials used in plastics like bisphenol A (BPA) and phthalates, a variety of pesticides and even some pharmaceutical agents.

Natural chemical examples include phytoestrogens (genistein and coumestrol).

Five reasons why studying EDCs are problematic
|You might wonder then, if EDCs are so bad, why are they still used in any product, not just cosmetics? The answer is that the science is very complicated and we don’t really know yet which compounds are really a problem. In fact there are five reasons why this is so complicated.

  1. Age at exposure.
  2. Latency from exposure.

  3. Importance of mixtures.

  4. Nontraditional dose-response dynamics.

  5. Transgenerational, epigenetic effects.


EDCs in cosmetics – what are they and how bad are they?
There are a handful of chemicals that are of concern in cosmetics related to endocrine disruption. Below is a list of the important ones and their current status.

First, recognise that there are probably six different common phthalates. Some of these have shown up as contaminants in blood samples and are believed to produce teratogenic or endocrine-disrupting effects. For this reason, the European Union has categorised dibutyl phthalate and diethylhexyl phthalate as Category 2 reproductive toxins. In the US, the FDA has moved to restrict the use of DEHP and DBP in pharmaceuticals and medical devices.

Both the FDA in the US and the SCCP in EU agree that there’s no clear data that the use of these ingredients in cosmetics pose a measurable hazard to consumers. The FDA is continuing to monitor the situation while the EU has taken a more conservative approach and decided to limit the use of some phthalates to only trace levels. From a regulatory perspective, the EU now has three categories for phthalates:

  • Accepted phthalates: considered safe for use in cosmetics: DEP.
  • Banned phthalates: banned from being added to cosmetics but allowable as ‘trace contaminants’ up to 100 ppm: DEHP, DBP and BBP.
  • Unregulated phthalates: These have not been regulated in EU but given their low usage (at least in perfumes) there is no quantifiable risk to consumers: DMP, DIBP, DCHP, DINP and DIDP.

Most recent data shows that when used at designated levels (around 0.2 percent) they are safe, particularly Methyparaben which is the most commonly used.

Bisphenol A (or BPA)

There is data showing BPA is hazardous but it’s only used in packaging not as part of any cosmetic ingredient.

Dioxin vs 1,4 dioxane

Dioxin is an EDC but not found in cosmetics.

Some of these EDCs are naturally occurring compounds.
For example, plant estrogens (also known as phytoestrogens) found in soybeans and other foodstuffs have been shown to have weak endocrine activity. However, the estrogenic activity of these materials, as measured under laboratory conditions, is generally far below that which is observed for estradiol – the naturally occurring form of estrogen in the human body. In addition, the levels at which these ingredients with potential hormonal properties occur in cosmetic and personal care products is significantly below levels that have been associated with the laboratory demonstrated endocrine activity.

Some studies say vitamin E this is an EDC while others say it protects against EDCs, and finally Tea Tree oil and Lavender oil have been shown to mimic estrogens and a few years ago there was a case reported where a couple of boys developed gynomastia (they grew breasts) after using tea tree and lavender products. But after a closer look at the data, it appears there’s nothing to be concerned about – for a thorough breakdown of this case check out the link:

So it seems like the EDCs which are of most concern in cosmetics really aren’t that concerning after all, but of course the debate still rages on.


EDCs in cosmetics: two sides of the story

Play it safe and act now

Some people take the stance that we should play it safe and act now. We don’t know if there are a safe exposure levels.
We don’t know if there’s a synergistic effect with mixtures of ingredients
It can take years for effects to show up and by that time it’s too late. So, if there’s even the slightest risk why not completely get rid of the right now? (Some people call this the Precautionary Principle.)

Get more data so we can make informed decisions

Others say we should collect more data so we can make more informed decisions. According to CosmeticsInfo, this topic is very controversial and is currently under-investigation by scientists in many countries. Right now the best science says that, “Although a variety of chemicals have been found to disrupt the endocrine system in studies of laboratory animals at very high doses and in some populations of fish and wildlife, there is no convincing evidence that ingredients used in cosmetic and personal care products cause endocrine disruption in humans.”

There are two reasons we need more data:

  1. We can’t do everything at once. We should focus on the chemicals that have been proven to be a high risk. For example, we should prioritise efforts to remove EDCs from foods before cosmetics.

  2. Let’s not accidentally make things worse. There are lack of good alternatives (for example, we don’t have any preservatives that works as well as parabens, so getting rid of them may cause other more pressing issues (like contamination leading to infections.) Also, we don’t have good alternatives that have better safety profiles. We don’t want to exchange a potential EDC for a known carcinogenic compound.

Also, for what it’s worth, historically once the cosmetic industry has had clear data that an ingredient is harmful, it has moved quickly to removed it.

The beauty brains bottom line
When it comes to learning which cosmetic ingredients pose a risk as an EDC, pay attention to legitimate scientific sources rather than fear mongering groups.

Consider what your personal risk factors are. Are you pregnant or likely to become pregnant soon? Then you may have a higher level of concern about potential effects upon your reproductive system.

If you do decide to look for alternative products then do your research. Learn what’s really in the products you’re considering and find out what trade offs in performance you might expect. That way you can make an informed decision.




Article reprinted with permission from


Publishing Information
Page Number:
Related Articles
Making the most of mineral make-up
Making the most of mineral make-up
Minerals used on the skin to beautify and camouflage is nothing new; Cleopatra used...
Exciting new brand for Beauty Sense
Exciting new brand for Beauty Sense
Waterlily has partnered with Beauty Sense as their New Zealand distributor. Founded in 2004 by...
Updates on skin care ingredients
Updates on skin care ingredients
Today’s consumers are pretty savvy when it comes to skin care ingredients and many want to...