Skinformation 'Toxic' chemicals and beauty products Toxic chemicals and beauty products. What should be avoided and why? August 2023 Are any of the following chemicals toxic to our skin? What are they found in and why would you avoid them? Benzophenone Benzophenone: this is a UV filter commonly found in Sunscreens. Some small studies have suggested that it and its derivatives oxybenzophone and avobenzophone can be hormone disrupters. This has led to many cosmetic formulations using alternative UV filters while further research is underway. Carbon black Carbon black: this is used in skincare as activated charcoal which is used to reduce sebum in skin so often found in cosmetics for oily prone skin. It can be drying and irritant to the skin although not known to be toxic. Butylated compounds Butylated compounds are antioxidant preservatives. There are concerns that they may have endocrine disruptive effects however this is thought to be in much higher concentrations than found in skincare for human beings. Coal tar Coal tar has been used for Dandruff and Psoriasis for years. At concentrations used in skincare, coal tar is considered safe although may be irritant and induce photosensitivity in some people. In much higher concentrations, there are concerns around coal tar being carcinogenic, in particular skin cancer. Again, this is at much higher doses than used in skincare Ethanolamines With Ethanolamines, the concern here is that under certain situations, ethanolamines can undergo a reaction to make nitrosamines which are potentially carcinogenic. Homosalate Homosalate is another chemical sunscreen filter that absorbs UVB light. It can also trigger allergic skin reactions in susceptible individuals. Similar to many other chemical sunscreens, there are concerns it can negatively impact on aquatic ecosystems. As it can penetrate the skin, there are concerns that it can disrupt human hormones. It is absorbed through the skin which makes some concerned about its ability to cause harm to disrupt the endocrine hormone system which in theory can affect thyroid function and fertility. Guidelines have been set on the safe levels of homosalate that can be used and further research is needed to fully understand its impact on the endocrine system. Formaldehyde Formadehyde in skincare arises as a by product from formadehyde- releasing preservatives such as quaternium- 15 and DMDM Hydantoin which gradually release formaldehyde over a period of time in order to prevent micro- organism overgrowth such as bacteria. Formaldehyde can irritate the skin and can trigger allergic contact dermatitis in susceptible individuals. Again, there are regulations on how much formaldehyde releasing preservatives are used in skincare products. Hydroquinone Hydroquinone is commonly used in prescription based creams to lighten dark areas on the skin such as in Melasma or large sun spots. In the UK it is prescription only, so comes from a doctor who should assess the patient's skin. At high concentrations or in susceptible individuals it can trigger skin irritation. Used for prolonged periods it can cause a paradoxical darkening or discolouration of the skin known as exogenous ochronosis. It can make skin sensitive to sunlight leading to unexpected burns. When used in large amounts over a prolonged period it can be associated with low birth weight in a fetus. Mica Mica is a mineral often used in skincare and make-up to give a shimmer- like finish. It can be irritant to susceptible individuals. Larger particles of Mica can cause sensitivity to light leading to unaffected sunburns. There are concerns that when inhaled, it can exacerbate respiratory problems. As it is mined, it can be contaminated by highly toxic heavy metals such as mercury therefore it is important that skincare companies using Mica have responsible supply chains that limit contamination. Acetone Acetone is used as a solvent in skincare especially nail varnish remover. It can trigger dryness and irritation in susceptible individuals. It is highly flammable therefore must not be used around candles, those smoking or open fires. It can disrupt the skin barrier leading to irritation and dryness. Octinoxate Octinoxate is another chemical sunscreen filter. There is evidence that it can disrupt hormones by mimicking oestrogen weakly. The actual impact this may have on a human adult is unknown and further research is needed. As with other sunscreen filters, it can trigger skin irritation and allergic dermatitis. Interestingly, it can potentially cause sensitivity to light in susceptible individuals leading to paradoxical sunburns (eg the filter which is meant to prevent sunburn causes sunburn). Similar to Oxybenzone, octinoxate can cause coral bleaching and may have an impact on the coral DNA. It is banned in certain regions of the world due to the potential to affect coral reefs. More research on whether the risk is theoretical or not is needed but in response to the possible concern, several manufacturers have removed the implicated filters from their sunscreens Parabens Parabens are very commonly used preservatives as they prevent the growth of bacteria, moulds and yeast. The potential risks are skin irritation and the risks of hormone disruption. It has weak oestrogen mimicking abilities which are thought to disrupt the natural order/ balance of hormones. It has been found in some breast cancer tumours although whether this is coincidental or causal is not understood. Various regulatory bodies have come to the conclusion that Parabens in the concentrations used in skincare are unlikely to be hazardous to skincare; further research is ongoing. P-phenylenediamine P-phenylenediamine, also known as PPD, is commonly used in hair dye and is known to be an important trigger for allergic reactions to hair dye, some of which can be so severe as to be potentially life threatening. This is why a patch test is mandated in hair dyes. PPD is also found in black henna. Triclosan Triclosan is a commonly used antimicrobial which can extend the shelf life of numerous products. It has been associated with a number of skin toxicities including skin irritation, contact allergic dermatitis and antibiotic resistance when used for prolonged periods of time and in high concentrations. It has been banned in some countries as an anti- microbial wash. As it broadly targets all bacteria including normal skin commensals, it is thought to affect the normal balance of microorganisms in the skin microbiome which can lead to exacerbation of inflammatory skin conditions. Are there any other toxic chemicals in products that are not good for our skin? Thankfully, the UK and EU have extremely vigorous cosmetic testing so provided you are getting skincare and cosmetic products from reputable retailers where composition testing has occurred it is unlikely that a product will contain chemicals toxic to skin. However, if you have purchased skincare online or from outside UK/ EU it is worth looking through the ingredients lists. Sometimes ingredients such as potent steroids, hydroquinone and in some cases Mercury may have been used, especially in countries where Mercury is still permitted in low doses in skincare. What fragrances can be problematic for our skin? Each individual is different so while one person is highly sensitive to fragrances in skincare, may not be. The other issue is that the exact fragrance chemical composition may be difficult to identify as the INCI list may only have “fragrance” or “parfum” as the ingredient. Nevertheless, the commonest fragrances that cause irritation and contact allergic dermatitis include limonene and citronella which both give a fresh citrus scent and linalool which has a floral scent. Musk based, Cinnamon based and Sandalwood based fragrances can also be problematic. It’s also important to note that plant extracts such as tea tree oil can be used as fragrance and can be highly irritant to susceptible individuals. If in doubt, I would recommend patch testing. So the main takeaways are nearly all these named compound can potentially irritate the skin and in some, cause allergic reactions. Some are thought to disrupt the endocrine system although definitive research evidence is lacking. Some can harm aquatic ecosystems- this is important for coral reefs. Dr Mary Sommerlad, Consultant Dermatologist Donate to skin disease research Protect your skin from the sun with Dr Mary Sommerlad By donating to skin disease research you are helping us to find treatments and cures for common conditions like eczema, acne and psoriasis, potential killers like melanoma skin cancer and rarer conditions like Stevens-Johnson Syndrome. Thank you. Manage Cookie Preferences