If you have ever looked on the back of a bottle of shampoo, foundation or soap you will be familiar with the never ending list of ingredients we all assume are safe.
But some dermatologists and aesthetic experts say many of these chemicals are irritating to our skin, polluting our environment, and, in some cases, are toxic.
These chemicals can not only cause allergic reactions for some, many are also suspected carcinogens, experts say.
Here, MailOnline reveals the ingredients dermatologists would avoid in beauty products.
Benzophenone is commonly found in sun creams, nail polish, foundation, hair spray and even some shampoos
Benzophenone is commonly found in sun creams, nail polish, foundation, hair spray and even some shampoos.
It’s designed to protect the skin from UV light, as well as stop products from losing their scent and colours in response to the glare of sunlight.
But studies suggest that while benzophenone is safe in small doses, it can act as a hormone disrupter by acting like the female sex hormone oestrogen in the body — meaning it can potentially hamper growth, fertility and reproduction.
Mary Sommerlad, a consultant dermatologist and British Skin Foundation spokesperson, said: ‘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.’
She added: ‘This has led to many cosmetic formulations using alternative UV filters while further research is underway.’
Benzophenone can also be toxic to liver cells, studies in animals suggest.
The European Food Safety Authority says benzophenone is a known toxicant because it can cause liver hypertrophy — when the liver becomes enlarged.
Carbon black is a dark powder used as a pigment in eyeliner, mascara and lipstick.
It is also used in some products containing activated charcoal, such as face masks and scrubs.
Dermatologists say it can be irritating to the skin.
‘This is used in skincare as activated charcoal which is used to reduce sebum in skin. So [it is] often found in cosmetics for oily prone skin,’ says Dr Sommerlad.
She added: ‘It can be drying and irritant to the skin, although not known to be toxic.’
Ethanolamines are chemicals made up of amino acids and alcohols.
The colourless sticky liquids are widely used in the production of toiletries, such as soap, shampoo and shaving cream.
It is not a banned substance and can also be used in cosmetics.
But there are fears it could be carcinogenic.
Dr Sommerlad said: ‘The concern here is that under certain situations, ethanolamines can undergo a reaction to make nitrosamines which are potentially carcinogenic.’
Nitrosamines — chemicals known to have been carcinogenic for decades — are not intentionally added to products but form due to a reaction between other chemicals.
But experts say this can only happen when ethanolamines, such as triethanolamine (TEA) and diethanolamine (DEA), are used in the same product as preservatives.
Ethanolamines are chemicals made up of amino acids and alcohols. The colourless sticky liquids are widely used in the production of toiletries, such as soap, shampoo and shaving cream
Formaldehyde is found in nail polish, hair straightening products and lash glue, says Simon Thorpe, an advanced aesthetics practitioner at Thames Valley Aesthetics in Berkshire.
The chemical makes its way into cosmetics when formaldehyde-releasing preservatives — such as quaternium-15, DMDM hydantoin and diazolidinyl urea — are added to products to increase their shelf-life and prevent bacterial contamination.
Mr Thorpe recommends staying away from products that contain formaldehyde because it can irritate the skin and cause contact dermatitis — a type of eczema.
Health chiefs warn that it can cause blisters and hives if used in high quantities.
But there are regulations aim to control the chemical’s negative side effects.
Aesthetic nurse Amanda Azzopardi, from Amanda Azzopardi Aesthetics in London, said: ‘Formalin, quaternium-15, and diazolidinyl urea, are used as preservatives in some products.
‘They can release formaldehyde over time, which can cause skin irritation and allergies.’
The chemical has also been classified a carcinogen, a cancer-causing chemical in humans, by the International Agency for Research on Cancer.
Formaldehyde has been linked with leukaemia and tumours in the nose of workers exposed to large quantities of the chemical over many years, experts say.
However, exposure over short periods of time is unlikely to have the same level of risk.
‘Fragrance’ is often featured in the ingredient list for beauty products.
But the term is broad and may refer to a scent that can trigger a reaction in some product users, warns Mr Thorpe.
Cinnamon, sandlewood, tea tree, citronella and linalool, which has a floral scent, are all common triggers of skin irritation and contact allergic dermatitis, experts say.
Cinnamon, sandlewood, tea tree, citronella and linalool, which has a floral scent, are all common triggers of skin irritation and contact allergic dermatitis, experts say
It can be difficult to identify whether a product has a fragrance that will trigger a reaction in someone, as it may only be referred to as ‘fragrance or ‘parfum’ in the ingredient list, says Dr Sommerlad.
If you are unsure whether your skin will react to something, dermatologists recommend patch testing first on a small area of skin.
Homosalate is a widely-used chemical in sun creams and skincare products with SPF.
But there are concerns the substance can cause serious allergic reactions as well as harm aquatic life by damaging coral reefs, says Dr Sommerlad.
Like other UV filters, it has been suggested that homosalate is a hormone-disruptor.
Dr Sommerlad said: ‘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.’
However, that doesn’t mean suncream isn’t safe, as guidelines have been set on the safe levels of homosalate that can be used, Dr Sommerlad said.
But she believes that further research is needed to fully understand its impact on the endocrine system.
Frequently found in skin lightening products such as bleaching creams and also hair dyes, hydroquinone can, in high concentrations, lead to skin irritation, burns and complications in pregnancy.
But in the UK, hydroquinone can only be found in prescription products and is usually used to lighten dark areas on the skin such as in melasma or large sun spots.
Consumers should be wary of products they buy in countries where this ban is not in place.
Frequently found in skin lightening products such as bleaching creams and also hair dyes, hydroquinone can, in high concentrations, lead to skin irritation, burns and complications in pregnancy
Dr Sommerlad said: ‘At high concentrations or in susceptible individuals it can trigger skin irritation.
‘Used for prolonged periods it can cause a paradoxical darkening or discoloration 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 foetus.’
Mica is what gives your bronzer and highlighter a shimmer-like finish.
But the mineral can be contaminated by heavy metals, irritate some skin types and make the skin more likely to burn, says Dr Sommerlad.
And there are concerns it can exacerbate respiratory problems if inhaled.
Although the levels of heavy metals is usually regulated, some mica-containing products from overseas could be exposed to mercury when being mined.
‘It is important that skincare companies using mica have responsible supply chains that limit contamination,’ says Dr Sommerlad.
The chemical UV filter octinoxate is commonly used in sun cream, shampoo, nail polish and some moisturisers.
It is suspected that the chemical — the most common UV filter used worldwide — interferes with hormones by mimicking oestrogen.
The actual impact this has on humans is not known, experts say.
But it can also cause skin irritation and allergic dermatitis, says Dr Sommerlad.
‘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).’
Octinoxate may also harm marine life by causing coral bleaching and is banned in certain regions of the world, such as Hawaii and Palau Island, over this concern.
Parabens are the reason our beauty and hair products have a shelf life of months or even years.
Found in a whole range of products from shampoo to mascara, they are commonly used to prevent the growth of bacteria, moulds and yeast.
But many dermatologists have put the preservative on the naughty step.
Propylparaben and Iosbutylparaben, which are both part of the paraben chemical family, can be irritating to some skin types, says Mr Thorpe.
Dr Sommerlad warns it may also disrupt hormones.
She said: ‘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.’
Phenylenediamine, also known as PPD, is one of the reasons patch tests are mandatory when getting your hair dyed.
Also found in black henna, it is known to trigger allergic reactions, which in some cases can cause life-threatening anaphylaxis.
The chemical can also trigger allergic contact dermatitis and exacerbate eczema.
Triclosan is added to products such as soap, hand gel and toothpaste to prevent bacterial contamination
Toluene, found in crude oil, is used in nail varnish to hold its colour and create a smooth finish. It is also added to some creams as a stabiliser and antioxidant.
Although in small doses it’s thought be harmless, in higher concentrations it can be dangerous for pregnant women and affect a baby’s development.
‘Prolonged exposure to high levels of toluene can have harmful effects on the nervous system and may be particularly risky for pregnant women’, says skin and beauty expert Caroline Brooks, founder of The Glasshouse Salon & Spa in Dubai.
However, the concentration of the chemical does depend on the product.
She added: ‘It’s important to note that the safety of these chemicals can vary depending on their concentration, frequency of use and individual sensitivities.’
Dermatologists advise people to read the labels of their cosmetics to make an informed decision and consult with healthcare professionals or dermatologists if they have concerns about certain ingredients or potential allergies.
Triclosan is added to products such as soap, hand gel and toothpaste to prevent bacterial contamination.
Fears that it is linked to hormone disruption, osteoporosis, antibiotic resistance and bowel cancer has seen it banned in some countries, including the US, though not in the UK.
But many manufacturers have voluntarily removed the chemical from products.
Dr Sommerlad said: ‘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.
The chemical is thought to target all bacteria, including normal skin microbes, which can fuel skin irritation, says Dr Sommerlad.