Endocrine disruptors (ED) are chemicals that may interfere with the body’s endocrine system and produce adverse effects including developmental, reproductive, neurological, and immune effects in both humans and wildlife. Endocrine disruptors are chemicals substances, both natural and man-made:
- Dioxin and dioxin-like compounds,
- Polychlorinated biphenyls,
- DDT and other pesticides,
- Plasticisers e.g bisphenol A.
The most widely accepted definition for an endocrine disruptor chemical (EDC) is the one provided by the WHO, according to which:
“An endocrine disruptor is an exogenous substance or mixture that alters function(s) of the endocrine system and consequently causes adverse health effects in an intact organism, or its progeny, or (sub) populations.”
Measuring adverse effects or EDCs according to the current definition can be extremely complex, as adverse effects can appear decades later, or in progeny, or even by accumulation after several generations. Effects can be irrelevant in individuals or small groups but produce significant consequences in large populations (drops in fertility across animal species) and only be measured by epidemiological studies. A further challenge is understanding just how EDCs are able to program an organism to produce pathological effects later in life or in future generations by acting during development. Current research is looking into epigenetic effects of EDCs to evaluate pathological programming
What is the endocrine system?
The endocrine system refers to the collection of glands of an organism that secrete hormones directly into the circulatory system to be carried towards distant target organs. The major endocrine glands include the:
Gastrointestinal tract and
Endocrine disruptors can be found in many everyday products :
Metal food cans
Personal care products
ECDs can cause anything from irregular periods, hormonal breakouts, acne and (in very extreme cases) birth defects, illnesses and cancer. In this article, we are going to concentrate on endocrine disruptors which can be found in cosmetics including skincare products, fragrances, plastic containers, nail polishes, and sunscreens.
Recent research Endocrine Disruption by Mixtures in Topical Consumer Products published in 2018, shows that endocrine disruptors may pose the greatest risk during prenatal and early postnatal development when organ and neural systems are forming. There is a potential endocrine disrupting effect of mixtures of endocrine active substances, even where those ingredients have been tested and confirmed not to produce adverse effects, cumulative action can result in endocrine disruption. Cosmetics applied on the skin on a daily basis, are a potential source of combined endocrine actives along with potential cumulative effects or synergistic [ingredient] action.
The article offers a summary from this research, highlighting cosmetic ingredients that are known or suspected to have any sort of endocrine action include several families of compounds:
The most stringent cosmetic regulations are the current EU regulatory framework (Regulation EC No 1223/2009 on cosmetic products) which provides an extensive list of banned ingredients or substances but it does not contain a list of allowed ingredients. The choice to use any ingredient or substance which is not banned or regulated is left to the manufacturer, provided the completion, of a safety assessment procedure, the CPSR (Cosmetic Product Safety Report). The CPSR is kept by the manufacturer itself (at an address specified on the cosmetic label) and shall be available for authorities in case of request but it is not required to be submitted for approval.
BISPHENOL A (BPA)
USES // The most common use of BPA is as a precursor of several plastics and epoxy resins, including polycarbonates and vinyl derivatives. As such, BPA is found in a wide range of containers, accessories and primary packages
RISKS // Can leak in traces to the cosmetics and ingredients, studies on animals and in vitro testing on human cells have linked BPA exposure with breast and prostate cancers, obesity, neurobehavioral problems, and reproductive abnormalities. Babies and young children are more vulnerable to its effects due to their development stage and rates of metabolism, products for this group have caused the most concern.
USES // Parabens (p-hydroxybenzoic acid esters) are used as antimicrobial preservatives and are so common in the environment that traces have been found in drinkable and mineral water samples. The EU (The European Commission) and ASEAN (The Association of Southeast Asian Nations) banned five parabens (isopropylparaben, isobutylparaben, phenylparaben benzylparaben; and pentylparaben) in 2014 and 2015 respectively. Other parabens still commonly employed in cosmetics because they were judged as safe include: Propyl-paraben Methyl-paraben Ethyl-paraben and Butyl-paraben.
RISKS // In vitro studies (Latin for within the glass) demonstrated that these molecules can damage the DNA and interfere with the normal mitochondrial function. Their ability to increase the proliferation of human breast cancer cells has also been demonstrated. However, a clear connection between parabens exposure and cancer risk has not been proved yet. The main factor used to support the safety of these molecules is the fact that their ability to activate estrogenic responses is extremely low and would require doses thousands of times higher than the ones used in consumer products. This consideration, despite being valid in itself, does not account for non-monotonic responses and mixture interactions. Parabens, even if considered to be safe on their own, should still be regarded as endocrine active substances and as such should lead to further investigation when combined with other known EDCs or endocrine actives.
USES // Antimicrobial agent with endocrine active properties, this substance has been banned by the FDA in 2017 for unrelated concerns (lack of efficacy).
RISKS // Triclosan is considered as a weak potential endocrine disruptor it is extremely common in cosmetics, detergents and other consumer products. Triclosan is almost ubiquitous and exposure is constant and extensive over time It is currently classified as a contaminant of emerging concerns, mainly due to its demonstrated absorption as it has been detected in breast milk, blood, and urine. The substance has been associated with increased fetal testosterone levels in humans and higher weight at birth.
USES // Cosmetic preservative.
RISKS // Formaldehyde, and paraformaldehyde are allowed in cosmetic products up to 0.2% when used as preservatives (even if Formaldehyde may be used up to 5% if used in nail hardeners) according to the Cosmetic Eu regulation 1223/09. However, some other preservatives such as Benzylhemiformal, Sodium Hydroxymethylglycinate, Bronopol, Diazolidinyl Urea, and Imidazolidinyl urea can decompose in aqueous and polar solvents to release some or all of their formaldehyde content. The monomeric form formaldehyde has been shown to have long-term low-dose effects on ovary function and to damage spermatogenesis in animal models and to be able to cross the placenta and affect differentiation and hormone functions in human cells and as such should be regarded as a potential endocrine active.
FRAGRANCE - MUSK
USES // Synthetic fragrances include several substances that are currently being investigated as endocrine actives and thus potential EDCs.
RISKS // Substances such as musk xylene or musk ketone are very resistant to degradation and can thus accumulate in the environment, musk xylene has been listed as a substance of high concern by the EPA and is both very persistent and capable of high levels of bioaccumulation. According to available literature, nitro musks are not easily absorbed through the skin, with very low levels found in body fluids and excretion even after several hours from application. Nitro musks have been demonstrated to increase proliferation in vitro on human breast cancer cells. Despite the ongoing controversy, the European Union has established maximum authorized concentrations for musks ketone 1.4% and xylene 1.0% and banned them in oral products. Musks ambrette, tibetene, and moskene were prohibited.
USES // Widely used fragrance ingredient.
RISKS // Has been investigated for possible endocrine activity, however, no direct correlation with adverse effects have been observed in animal studies. Polycyclic musks such as HHCB (Galaxolide) and AHTN have also been objects of several studies to assess its ability to bind and activate endocrine receptors. HHCB has been linked to activation of Estrogen receptor. AHTN has been confirmed as a weak endocrine activator. Other potential endocrine active in fragrances include diphenyl ether several terpenes and essences and benzylacetate.
USES // Cyclosiloxanes include very persistent, very bioaccumulative compounds. Among them, Siloxane D5 was classified as a substance of very high concern by the European Union.
RISKS // Siloxane D5 has been scheduled for limitation to 0.1% in wash-off cosmetics starting in 2020. Cyclic silicone polymers based on cyclosyloxanes (Cyclomethicones) have been detected ubiquitously in the environment due to their use in medical and cosmetic products. Cyclomethicones have been proved to be toxic for aquatic organisms and are known to bioaccumulate in aquatic life in laboratory studies.
USES // A family of organic compounds and are used as raw materials for detergents, emulsifiers, wetting agents and dispersion agents, as well as anti-oxidants. Wildly used as components of plastic containers. Listed as biodegradable but are expected to bioaccumulate.
RISKS // Production is prohibited and the substances are being replaced with alcohol ethoxylates Nonylphenols are capable of mimicking estradiol and bind the estrogen receptor only partially, resulting in a relatively weak effect. In humans, induction of the expression of placental and uterine proteins may be indicative of the compound’s ability to permeate the placental barrier and reach the fetus during pregnancy.
USES // Chemical Sunscreens.
RISKS // Several UV filters were either investigated for or are suspected to have some endocrine activity. These include 2-ethylhexyl 4- (dimethylamino) benzoate (Ethylhexyl dimethyl PABA, or Padimate O), Octinoxate (Ethylhexyl Methoxycinnamate) and benzophenones. Literature also pointed to nanoscale physical filters as potential substances with reproductive toxicity and endocrine effects. Recent population studies have demonstrated that large groups of people can be exposed to UV filters in the environment, even without direct administration and in seasons not associated with the use of sunscreens, due to the environmental ubiquity of some of these compounds.
The sunlight-mediated mutagenicity of Ethylexhyl dimethyl PABA has been demonstrated and may soon be delisted in the EU cosmetic regulation. Most benzophenones show endocrine action at some levels through the estrogen pathway.
USES // A common source of phytosterols are soy extracts used in cosmetics, including soy isoflavones (genistein, daidzein, and glycitein) and soybean oil.
RISKS // Several phytosterols from vegetal sources have been connected with endocrine effects. Coumestrol and resveratrol are both known to show a very high affinity for estrogen receptors. Soy isoflavones were reported to be natural selective estrogen receptor modulators with tissue specificity, resulting in estrogenic effects in some tissues.
Genistein is considered the most endocrine active of soy-derived compounds and is used as a natural substitute for estrogen replacement therapy in postmenopausal women. However, the studies focused on phytoestrogen exposure via dietary pathways, instead of administration through topical products. Despite the effects observed in animal models, soy and soy derivatives are mostly deemed safe for dietary consumption. The role of soy-derived phytoestrogens in cosmetics would need to be investigated separately, especially in mixtures and formulations containing more known or potential endocrine actives.
Several other phytosterols are known or suspected to have endocrine effects. Serenoa Repens is known and used for its antiandrogenic effects (testosterone blockers) and several extracts from other plants, such as Licorice or Chinese Peony are known to display similar effects.
SKIN WHITENING AGENTS
USES // Compound used in skin whitening.
RISKS // Kojic acid has been demonstrated to interfere with either iodine organification or iodine uptake by the thyroid, resulting in altered thyroid functions. Resorcinol has a similar effect on thyroid function and hormone production. Arbutin, extracted from the Chinese yam plant has been shown to determine estrogenic effects.
WHAT CAN YOU DO MINIMIZE YOUR CHEMICAL EXPOSURE
ALWAYS READ THE LABELS // Cosmetics have labels so read them! Once you know which ingredients to look out for you can make a more informed choice and swap your cosmetics and skincare products to ones that do not contain EDCs.
MY PERSONAL OPINION // For those of us with health issues, compromised immune systems, the onset of adult acne, or autoimmune conditions - the list goes on! our bodies are already overwhelmed. Anything you can do to lessen and or reduce your exposure to environmental pollutants can only help.
I recommend switching to COSMOS Certifed Organic Cosmetic Products, as the raw materials (ingredients) are grown without the use of harmful pesticides known to be EDC, using sustainable farming principals. The allowed ingredients are highly regulated by the Organic governing bodies, for example, COSMOS and will reduce your exposure to the potential endocrine disruptors listed in this article. However natural substances such as soy also have hormonal effects, so make sure you read the labels!
Four important points about endocrine disruption to remember
- Low dose matters
- Wide range of health effects
- Persistence of biological effects
- Ubiquitous exposure
By the way for those of you wondering the featured image for this blog post is thyroid gland cells.
Use sunscreens with physical blockers - such as zinc oxide or titanium dioxide.
Avoid polycarbonate plastics - used in Cosmetic Bottle (a number "7" in the recycling triangle means the plastic is polycarbonate or "other", and a sign it may contain BPA).
Avoid Synthetic fragrances - in perfumed personal care and household products choose natural fragrances from essential oils.
Avoid parabens - check the ingredients list for propyl-, isopropyl-, butyl- and isobutyl-parabens. (Parabens, even if considered to be safe on their own, should still be regarded as endocrine active substances and as such should lead to further investigation when combined with other known EDCs or endocrine actives.)
Choose Certified Organic Person care products.
Avoid Antibacterial soaps and toothpaste which can contain triclosan (liquid soaps and toothpaste) and triclocarban (bar soaps), so read the labels then read them again.
Until next time,
be human, be kind, be you.
Endocrine Disruption by Mixtures in Topical Consumer Products
Emiliano Ripamonti, Elena Allifranchini, Stefano Todeschi and Elena Bocchietto
Inventory of Cosmetic Ingredients filed by the European Commission