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Substances of 1,4-dioxane, Allergy-causing Preservatives or Free Formaldehyde Found in Over 70% of Shampoo Models Be Wary of Product Claims That May Not Live Up to Expectations

  • 2017.08.15

In recent years, manufacturers of shampoo products have been rolling out a wide array of claims, such as "non-silicone", "natural ingredients/organic", and even anti-hair loss.  Are these products really free of allergy-causing substances?  A Consumer Council test on 60 shampoo models has revealed that over 60% of shampoos contained 1,4-dioxane, and 20% allergy-causing preservatives MIT (methylisothiazolinone) and/or CMIT (methylchloroisothiazolinone).  Some models were found without detailed ingredient labels, seriously affecting consumer choice.  The Government is urged to regulate labelling of cosmetics products, requiring full disclosure of ingredient information to enable easy reference of consumers, in particular those with skin allergy problems.

Included in the test for chemical and microbiological analyses were 60 models of different shampoo products available in the market – 39 models with claims they are suitable for consumers in general; 3 specifically for women and 7 men; and the remainders 11 for users with hair loss problems.

The presence of 1,4-dioxane was detected in 38 models with the amount ranging from 1.1ppm to 24ppm, which all fell within the Mainland's "Cosmetics Safety and Technical Standards for Cosmetics 2015" limit of 30ppm.  Nonetheless 7 of the models (including 5 for ordinary users, 1 for men and 1 for users with thinning hair or hair loss problem) that had a 1,4-dioxane content between 12ppm and 24ppm, exceeded the EU Scientific Committee on Consumer Safety (SCCS) recommended safety level (10ppm) for cosmetics.  In normal usage, however, these models are not deemed to pose safety risks to users.

1,4-dioxane is not an ingredient of cosmetics products, so not listed on the label.  Shampoo products with surfactants SLES (sodium laureth sulfate) or ammonium laureth sulfate are more susceptible to 1,4-dioxane contamination.  Among the 38 models with 1,4-dioxane detected, SLES were found on the ingredient labels or information provided by suppliers of most products and it is often listed on the top positions (no. 2 to 4) of the label.   Personal care products containing SLS (sodium lauryl sulfate) and SLES should be rinsed thoroughly after use to avoid experiencing skin irritations for some people, like tautness and dryness.

Among the 12 models with CMIT and/or MIT preservatives found, 1 had CMIT/MIT combined total quantity exceeding the current Mainland and EU standard of 0.0015%, and 3 had MIT concentration exceeding the EU SCCS recommended safety level of 0.0015%.  It is worth to note that 1 of the models claimed suitable for users with thinning hair or hair loss problem.  According to a dermatologist, consumers with hair loss problem should pay extra precaution to the shampoo ingredients.  Applying shampoos with MIT or CMIT preservatives on open wound could have a higher chance of adverse discomfort reaction.    Further, 2 of these shampoo models do not have detailed ingredient labelling displayed in neither Chinese nor English for reference of consumers with skin allergy.

Be sceptical of product claims

Consumers are reminded to be wary of product claims such as hair breakage/damage prevention and hair loss reduction.  They could in fact only prevent hair breakage/damage due to combing, and have no lasting improvement to all kinds of hair loss.

The attention of consumers is drawn to some shampoo products containing common hair conditioning ingredients, silicones, for example, dimethicone.  The substance is capable of being adsorbed onto the hair surface to restore hair cuticle damage, leaving a smooth feeling and glossy look.  The fact is, the effect is temporary and could not really restore damaged hair.  To avoid silicones, consumers are advised to be careful in the choice of hair shampoos and conditioners.

The provision of information in product labelling came under scrutiny in the test.  It was found that 14 models failed to disclose full details of their ingredients in Chinese or English.  An analysis of the 13 models detected with MIT, CMIT and free formaldehyde, based on the test results and labelling information, produced the following findings – 4 made claims of "non-silicone", 4 of "mild and gentle quality", 3 each of "containing no parabens" and "no SLS", 3 of "natural ingredients/organic", 2 of "certified approval by dermatologists", and another 2 of "no colourants".  The truth is even if the products carry such labelling or descriptions, they do not indicate that they are completely free of allergy-causing substances.  The lesson to be learned for consumers is never to fully believe the advertising claims; instead they should always study ingredient labelling with care before purchase.

Many consumers have preference for shampoos with fragrances.  But fragrance and fragrance allergens are a common source of allergy in personal care products that could cause skin irritation.  Among the models, 43 were labelled to contain fragrance ingredients; 17 of them containing recognised allergy causing substances.

Price and quality don't necessarily correlate

The prices of the test models ranged from $45 to $390.  The top performers with the highest overall rating of 5 points were shared among 37 test models.  Interestingly, 22 of them (two-thirds) were in the price bracket of under $100, including the cheapest model.  The most expensive model, on the other hand, scored 2.5 points only, with MIT preservative concentration exceeding the recommended level of EU SCCS maximum concentration for safe usage.  The Council is emphatic that the product price or its advertising claims do not necessarily bear any relation with its quality or performance.  Consumers, particularly those with sensitive skin and other skin problems, should therefore make every effort to understand the product ingredients and labelling prior to purchase, and choose the products accordingly that most suit them.

In the test for heavy metals content, with the exception of a model detected with a trace amount of arsenic (0.18ppm), the rest had no detectable amount of mercury, lead, arsenic and cadmium.  Furthermore, all models were given a clean bill of health free of hormones, micro-organisms or pathogenic bacteria tested.

In choosing shampoos, consumers should also take heed of the following:

  • Choose a product that most suits the condition of your scalp, your skin and hair type;
  • Read the product ingredient information with due care.  If you are prone to skin allergy or are suffering from eczema and other skin problems, avoid choosing shampoos that contain MIT, CMIT and formaldehyde releasing ingredients;
  • Whenever possible choose products that are labelled with date of manufacture, expiry date and period after opening;
  • After use, take note of your head, face and other parts of body for unusual reactions such as itching, rash, etc.  Such unfavourable reactions may not necessarily occur immediately after initial use of the product.

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