The Dangers of Your Shampoo

Published on 17 February 2021 at 13:04

Picking a shampoo can quite literally be a life changing decision. The specific absorption rate of head tissues is higher than that of the skin in another part of the body. Scientists now have proof that an ingredient found in shampoo and other products can affect brain development in mice. 


There are 13 emissary veins which drain your brain through your skull. They are bidirectional: can take waste out or into the brain. There is significant absorption through the skin into the blood through topical application. Though different products mean different levels of exposure and concern. Using a lotion which soaks into the skin all day, causes a lot more exposure to chemicals, than a product which is quickly washed off. 


In spite of the subsequent layers of the skin, the epidermis, dermis and subcutaneous fat, substances can still be absorbed if they are small enough. That’s mainly the problem with nanomaterials.


The amount of a product or chemical absorbed by our skin depends on a variety of factors, including : Chemical Size, Skin Temperature, Skin Integrity, Chemical Concentration, Exposure Length, Area of Skin Exposed. 


The EU Cosmetics Directive (76/768/EEC) was adopted in January 2003 and most recently revised in 2013, banning 1,328 chemicals from cosmetics that are known or suspected to cause cancer, genetic mutation, reproductive harm or birth defects. 


Article 3 provides for safety of such products, taking account of labelling, and under Article 19 labelling must include a list of ingredients, established in descending order of weight. 


I have looked up the ingredients contained in my shampoo: L’Oréal Paris’ Elseve Energie “shampooing soin”. 


It contains mostly water but also ‘sodium lauryl sulphate’ which strips the skin of its natural oils which causes it to dry, irritate and cause allergic reactions. 


It is composed of Coco-betaine’ an allergen which rarely causes allergic skin reactions as it is a naturally derived from coconut oil. It also helps to hydrate skin and smooth hair. 


My shampoo also contains ‘Glycol distearate’. Formulations containing Glycol Stearate at levels of 2-5% reported no skin irritation or sensitization. However, > 4% should be considered. Interestingly, the concentrations of ingredients weren’t specified on the packaging of my shampoo.

My shampoo curiously contains ‘glycerin’. It is a medication used as a moisturizer to treat dry or itchy skin. So, on the one hand you have ingredients like sodium lauryl sulfate which dry your skin and then glycerin, compensating for those. Ironically though, the same emollients supposed to cure your skin can result in irritation. 


There are still 15 ingredients to go. One of them is ‘guar hydroxypropyltrimonium chloride’, which according to Paula Begoun, a Cosmetic Cop, is “truly one of the unsung heroes of certain types of cosmetic formulas”. It is as a conditioning agent for skin and hair. 


In 2008, Begoun created, an online product review database that claims to cover over 45,000 products from more than 300 brands.


Among the other ingredients, a familiar one is salt or ‘Sodium chloride’. The reason why would one need salt in a shampoo though is beyond my knowledge.


 ‘Sodium benzoeate’ is also on the list. It is safe for consumers, can be found in cranberries. It is an anti-fungal agent and acts against bacteria.


As for ‘Sodium hydroxide’, it can cause irritation to the skin and what’s worse: temporary loss of hair. Actually, workers may be harmed from exposure to sodium hydroxide. 


Most of these products pollute water, as they get used under the shower. For instance, PPG-5-CETETH-20-PEG-55 Propylene Glycol Oleate pollutes, on top of causing dermal irritation.


Concerning, ‘Salicylilc acid’, the primary negative side effect is its ability to irritate and dry skin in those that are very sensitive or those who overuse it. 


Limonene makes the list, being considered safe for humans with little risk of side effects. 

Actually, being a solvent of cholesterol, it can dissolve cholesterol-containing gallstones. It has a gastric acid neutralizing effect, relieving of heartburn and gastroesophageal reflux. Moreover, it is a well-established chemopreventive activity against cancers. 


As for ‘Fumaric acid’, the European Commission Scientific Committee on Animal Nutrition, found in 2014 that it is "practically non-toxic" but high doses are probably nephrotoxic after long-term use.


Another ingredient is ‘Linalool’, which according to the European chemicals agency 

causes skin irritation, allergic reactions, and serious eye irritations. These are a category 2 skin irritation and a category 1 skin sensitisation, under the Hazardous chemical information system.


Propylene glycol is reported as not meeting GHS hazard criteria by 6563 of 6697 companies, though only approximately 2% companies provided GHS information. This ones against reveals the bias behind this industry. 


Another interesting ingredient is ‘Carbomer’ or ‘Polyacrylic acid’ which is harmful in contact with skin and can causes severe skin burns. It is also harmful if inhaled, and toxic to aquatic life, according to the European Chemicals Agency. I think we have a winner.


As for ‘Octyldodecanol’, the CIR Expert Panel evaluated the scientific data and concluded it was safe for use in cosmetics. How could one not suspect lobbying though? 


There is ‘Citric acid’, a familiar name, a compound derived from lemon juice. It may cause category 2 skin irritation and respiratory irritation, according to the European Chemicals Agency. It can be used to preserve or as a disinfectant. 


Another ingredient is ‘Hexyl cinnamal’ a fragrance chemical, with low skin-sensitizing potency commonly used for positive control for predictive toxicology assays. 

However, the ECHA says it is very toxic to aquatic life with long-lasting effects. Also, it is an allergen within CosIng. 


Finally, this shampoo contains ‘Parfum / fragrance F.I.L C216183/1’. The Environmental Working Group found that most products that list fragrance contain the hormone disrupting chemical, phthalates. These have been linked to reduced sperm count, liver and breast cancers, reproductive malformation and diabetes. 


Fragrance is considered a trade secret under the Fair Package and Labeling act of 1966, allowing companies to not list ingredients, and for a good reason. 

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