Phthalates are endocrine disruptors but some are still used in various cosmetic products. Should we be worried? Dr Haran Sivapalan examines the evidence.
If you look at the ingredients listed on your favourite products it may well say ‘fragrance.’ If so, there’s a chance that the product may contain phthalates – molecules that are considered to be ‘endocrine disruptors.’
Currently, the EU Cosmetics Directive bans the use of over 1,300 chemicals in cosmetics and, in 2013, three “phthalates” were added to this list. But there are some that are still used in a variety of products including skincare, perfumes, hair sprays and nail polish. So, just what are phthalates and should we be concerned?
What are phthalates?
Phthalates are a class of chemically-related synthetic molecules, which are commonly used in manufacturing as ‘plasticisers’. This means they are added to plastics to make them more durable, more flexible and/or more viscous. For instance, phthalates are added to plastic bottles to make them more ‘squeezable.’ Given our widespread use of plastics, phthalates are seemingly ubiquitous – found in food packaging, window frames, vinyl flooring, clothing, medical equipment and, as discussed in this article, some cosmetics. About 3 million tonnes of phthalates are produced around the world every year.
Broadly, there are two classes of phthalates based on the size of the molecule. Their use in manufacturing also varies according to class. High molecular weight phthalates, which include (DEHP), are predominantly used in the manufacture of vinyl, PVC and other rigid polymers.
By contrast, it is the low molecular weight phthalates that are used in cosmetics. For example, dibutyl phthalate (DBP) is used in nail polish to make the product less brittle and prevent cracking. Dimethyl phthalate (DMP) is added to hair sprays to prevent the hair from becoming stiff by forming a thin malleable film around the hair. The phthalate most commonly found in cosmetics is diethyl phthalate (DEP), which is used as a solvent in many perfumes.
How are we exposed to phthalates?
In 2001, the Centre for Disease Control (CDC), a US public health agency, issued a seminal report stating that the metabolites of 7 phthalates (DEHP, DBP, BBP, DiBP, DiDP, DiNP and DNoP) were found in people’s urine. While this large study did not investigate any link between phthalates and disease, it did tell us that phthalates could easily get into the body. This is not surprising, given that phthalates both leech easily into the environment and are present in lots of consumer products.
So how do they get into the body? The main route of entry is thought to be via ingestion – that is, we swallow them. Phthalates, for example, may leech from plastic food packaging into the foodstuffs themselves. Children’s toys inadvertently placed into the mouth are another source of ingested phthalates. People are also exposed to phthalates by breathing in air and dust when indoors, as phthalates are a component of many building materials and indoor furnishings. On a smaller scale, the use of invasive medical devices, such as plastic IV drips can also introduce phthalates into the body.
And what about skin care products? There is some evidence to suggest that phthalates can slowly enter the body if applied to the skin (for example as part of a cream or topical insect repellent), although exactly how much gets absorbed has not yet been robustly quantified. Compounding this problem, the absorption of phthalates through the skin varies considerably from product to product and largely depends on the particular composition of ingredients. Moreover, some studies suggest that the amount of phthalates absorbed through the skin pales in comparison to that which is ingested. Clearly more research is needed in this area.
Do they harm the body?
When phthalates enter the body, they are generally broken down (metabolised) and the resulting breakdown products (metabolites) excreted in urine and faeces. Phthalates are metabolised relatively quickly and do not accumulate in the body. The issue, however, is that some of these phthalate metabolites (so-called “free monoesters”) may interact and potentially cause damage to the body.
What kind of damage do they cause? Phthalates are classified as Endocrine-Disrupting-Chemicals – they can potentially interfere with the complex systems of hormones that regulate our bodies. Growth, puberty, menstruation, the control of important nutrients in the body – these are all regulated by hormones. Research suggests that phthalates can specifically affect the function of oestrogens (hormones involved in female sexual development and reproductive health) and androgens (hormones such as testosterone, which itself is involved in male sexual development and reproductive health). Consonant with this, phthalates have been associated with various disorders of development, of puberty and of male and female reproductive systems.
In men, a recent (September 2016) review of the literature published in the journal Environment International suggested an association between high doses of phthalates (DEHP, DBP and DiNP) and reduced semen quality, genital abnormalities and reduced testosterone levels. For women, the same study concluded “phthalates are strongly associated with increased risk of type 2 diabetes, leiomyomata (fibroids), endometriosis, and breast cancer.”
It is important to remember, however, that the risk of these disorders is related to the dose of phthalates. To quote Paracelsus, the 16th Century physician and founder of toxiciology:
“All things are poisons, for there is nothing without poisonous qualities. It is only the dose which makes a thing poison.”
Low doses carry lower risks. Exposure to higher doses carries higher risks. In terms of what we consider safe exposure, scientists calculate a figure called the ‘No Observed Adverse Effect Level (NOAEL)’. Put simply, this the highest tested amount of a substance that has been shown to have no harmful effects on people or animals. Another related and useful figure is the ‘Tolerable Daily Intake’ or TDI. The TDI is the amount of a chemical in air, food or drinking water that can be taken daily over a lifetime without significant health risk.
According to reports issued by the US Food and Drug Administration (FDA) and the European Commission, the low doses of phthalates typically in many cosmetic products are under their respective NOAELs and unlikely to cause any harm.
How may phthalates cause harm?
They are three main ways by which phthalate metabolites can disrupt hormones such as oestrogens and androgens:
• by mimicking the effects of the hormone, thereby leading to overstimulation and exaggerating the effects of the hormone.
• by binding to receptors and blocking hormones. When hormones are prevented from binding to their receptors, they cannot carry out their normal functions in the body.
• by interfering with the breakdown and metabolism of hormones that occurs in the liver. This, in turn, can alter the amount and function of hormones.
On a related note, the risk of harm (particularly developmental abnormalities) from phthalates is much higher for fetuses in utero and newly born babies. This is partly because their underdeveloped metabolism is less adept at breaking down and excreting phthalates. Owing to this increased health risk in infants, some phthalates have been banned in children’s toys, both in the EU and the US.
What about phthalates in skin care products?
Most studies suggest that, while they are frequently found in cosmetic products (including skin care products), their concentrations are fairly low and, as such, do not pose a health risk. Furthermore, high molecular weight phthalates with greater evidence of health risks (such as DEHP) are rarely used in cosmetics.
That said, an American survey of 170 personal care products found that 90% of skin toners and nail polishes contained the low molecular weight phthalate DEP. A Korean study also found DBP and DEP in a high proportion of band name perfumes and nail polishes. In 2007, a report by the Scientific Committee on Consumer Products found trace amounts of DBP, DEHP, DINP, DIDP, DIBP and BBP in a selection of cosmetics. Crucially, all these studies reported that the quantities of these phthalates were far below their NOAELs and TDI levels – they did not pose a health risk. But if you are concerned there are a number of nail polishes on the market now that claim to be phthalate free.
In line with this, according to a review of the evidence by the U.S. Food and Drug Administration (FDA), there is no strong evidence for an association between phthalates in cosmetic products and any health risks. Consequently, they feel there is not a “sound, scientific basis to support taking regulatory action against cosmetics containing phthalates.”
By contrast, the EU has banned the use of DEHP, DBP and BBP in cosmetics. DEP, the phthalate most commonly found in cosmetics, is currently considered to be safe to use and is permitted for use in cosmetics.
In reality, the ban on certain phthalates doesn’t mean all cosmetics are phthalate free. Leeching from equipment in the manufacturing process can unintentionally introduce phthalates to cosmetics. More egregiously, some companies can sneak banned phthalates into cosmetics by branding them as ‘fragrances’ rather than plasticisers.
Should we lose sleep over this? In 2007, the European Commission tested 36 perfumes and came to the conclusion that concentrations of DEHP, DBP and BBP up to 100 ppm (parts per million) do not pose a health risk.
Take home points
• Phthalates are in many consumer products, including cosmetics.
• Phthalates can enter the body via skin contact, but more research is needed to accurately assess how much is absorbed.
• Some studies have linked high doses of phthalates (particularly DEHP, DBP and DiNP) to problems with the male and female reproductive systems.
• Infants and foetuses in utero are more vulnerable to health risks from phthalates.
• Cosmetic products generally have doses of phthalates that are too low to be of significant health risks.
• DEP, the phthalate most commonly found in cosmetics, is of low toxicity and currently deemed safe by the EU for use in cosmetic products.
• In the EU (but not the US), DEHP, DBP and BBP are banned from use in cosmetics. Low doses of these phthalates still found in cosmetics are nevertheless thought to be safe.
Manufacturers are heeding the public’s concern over what the products they are putting on their body’s contain and there is a growing number of products available that claim they are free of all sorts of ‘nasties’ including phthalates, parabens and PABA.
If you are concerned about phthalates in your products you can contact the manufacturer and ask if their products are phthalate free if the packaging does not make that clear. There are also various websites that list phthalate free products but many are ‘opt-in’ as opposed to independently assessed – that is the manufacturer supplies the information to be added to those lists and it may not be comprehensive.
Centers for Disease Control and Prevention (2001). National Report on Human Exposure to Environmental Chemicals. Available online: https://www.cdc.gov/exposurereport/
European Commission (2007). Opinion on Phthalates in Cosmetic Products. Available online: http://ec.europa.eu/health/ph_risk/committees/04_sccp/docs/sccp_o_106.pdf
FDA (2016). Phthalates. Available online: http://www.fda.gov/Cosmetics/ProductsIngredients/Ingredients/ucm128250.htm
Guo, Y., & Kannan, K. (2013). A survey of phthalates and parabens in personal care products from the United States and its implications for human exposure. Environmental science & technology, 47(24), 14442-14449.
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Schettler, T. E. D. (2006). Human exposure to phthalates via consumer products. International journal of andrology, 29(1), 134-139.