EU cosmetic regulations are a significant barrier to innovation and to the replacement of current, less than ideal hair dye materials, argues Bob Hefford
It is well known that some of the dyes used in hair colouring are classified as hazardous chemicals. Hair colouring products are, however, safe for use when assessed correctly and this position is endorsed by the cosmetic regulators within the EU Commission. However, we do know that some of the hair dye precursors used in oxidative colouring products are sensitisers and can elicit a pretty severe reaction in (the few) customers who have become sensitive. This allergic effect has been the cause of much discussion over many years and continues to feature regularly in certain newspapers. Upgraded warnings on most oxidative hair colouring products are going to be required by the cosmetic regulations within the EU at some time in the near future and some companies are implementing these upgraded warnings on a voluntary basis.
The main villain in the world of hair colouring is the hair dye precursor para-phenylenediamine (PPD) or 1, 4-diaminobenzene. Lagging a little way behind in the hate stakes is para-toluenediamine (PTD) or 2-methyl-1, 4-diaminobenzene. These are the materials which generally cause the headlines in certain newspapers such as ‘My hair dye turned me into the elephant woman!’. They are called hair dye precursors as they are not coloured themselves but react in the presence of an oxidising agent to form larger coloured molecules which are trapped within the structure of the hair.
These two aromatic diamines were discovered and initially developed in the 19th century and are still used in oxidative hair colouring products today. So after 130 years or so of innovation by many of the best brains in the business it is an interesting question why these materials are still in use. Although a matter of opinion it is almost certainly true that if these materials were discovered today they would not be allowed for use in cosmetics.
One of the main reasons why these hair dye precursors are still used in products today is that they can work extremely well at colouring the hair in a permanent (until the hair grows out) fashion if they are formulated correctly. If the correct set of hair dye precursors is combined with an oxidising agent (nearly always hydrogen peroxide) in the presence of ammonia at about pH 10.5 almost any hair colour can be achieved.
Ammonia and hydrogen peroxide are present in the product to start the hair colour forming reaction and to lighten the hair. It is this simultaneous lightening
ability (of the hair itself and any previous artificial colouring perhaps by up to two to three levels) of this type of formulation which really sets oxidative hair colouring above most, or all, other ways of colouring the hair.
ALTERNATIVE COLOURANTS
So what is someone who wants to colour their hair but is unable or unwilling to use products that contain PPD or PTD to do?
One alternative is to use products containing (non-ionic) direct dyes which can colour hair but generally only in a semi-permanent (lasting six to eight washes) or temporary (wash straight out) fashion. These dyes, sometimes called direct dyes, are applied to the hair at relatively high pH values in the presence of alkalis such as aminomethyl-propanol (AMP). But these products usually also contain synthetic hair dyes that may also be sensitisers, although of lesser potency than PPD and PTD. In addition, as these materials are used much less, there is a far reduced chance that a consumer will have become sensitive. Other direct hair dyes are cationic or anionic in character and each type has its own particular drawback when used to colour the hair.
NATURAL OPTIONS
Another alternative is to use natural hair dyes. These materials (often polyphenols) are present in plants and are generally similar to the direct dyes described previously. The use of plant derived materials to colour hair, as well as various parts of the body, goes back thousands of years, probably before recorded history. With the current trend towards the use of natural and renewable materials it is not surprising that the demand for natural hair colouring products is growing. It is also possible to obtain these dyes from organic sources so the demand can get even greater.
There are of course a number of technical drawbacks to using plant derived dyes to colour the hair and these include the following:
l They are generally not very stable to light
l They may not colour the hair to any great extent
l The colour may not last very long and may wash out
l The treatment time may be quite long to get a reasonable colour
l They cannot lighten the hair at the same time although the hair could be pre-lightened
l Use of the plant material itself to form the product is messy and unpleasant, thus the dye is best separated from the plant material first
l The dye may change colour or degrade under certain solution conditions, eg pH
With careful thought some of these technical issues can be addressed. One way of improving the uptake of dye by the hair is the addition of soluble metal ions, especially if the dye is anionic in character. This is also a very old practice within the hair colouring area and was probably discovered by accident when the early hair dye formulator, possibly pre-bronze age, decided to prepare his latest recipe in his newly discovered copper vessel. Other metal vessels were also used for this purpose, especially lead, and the use of ‘old wine’, ie vinegar or acetic acid, helped to lower the pH and dissolve some of the vessel making the metal ions available in solution. The use of metal ions in combination with dyes to colour textiles is well known and is known as mordanting.
Quite a large number of different natural hair colouring products can be purchased these days. However, this is generally through the internet or small specialist stores rather than from the well known large retailers. Care must be taken when choosing a product, however, as the producer’s idea of natural may not be the same as the customer’s. There are some products that claim to contain naturally derived ingredients which also contain amounts of conventional hair dyes such as PPD. The ingredients listing should always be consulted carefully.
Once the technological difficulties have been overcome as far as possible there does unfortunately remain the question of the regulatory hurdle that needs to be encountered. This hurdle is now very different in the EU to in the US and is getting more different, and difficult, all the time. See table 1 for the situation in the EU the time of publication.
At present there are only four materials on the supported list (of 117) hair dyes which could be considered to be naturally derived. These are:
l Lawsone or 2-hydroxy-1, 4-napthoquinone (an active colouring material found in henna)
l Lawsonia iInermis or henna (obtained as the dried and powdered leaves of the plant). This is described in the list of 117 materials as ‘synthetic henna’ which is presumably a mistake
l Indigofera tinctoria ext (natural)
l Curcuma longa (turmeric)
At the time of writing the first two materials have published opinions whereas the latter two do not. The opinion for Lawsone is very unfavourable although the author believes being contested so a further dossier and subsequent opinion are awaited. The opinion for henna is not very favourable either but less severe than for the active ingredient Lawsone. Interestingly the use of henna as a body paint has not been considered at all by the SCCS or any of its predecessors.
A FRESH APPROACH
An interesting product was recently launched by ACT (Advanced Cosmetic Technologies) in the US (http://www.actnaturals.com/). This product combines a mixture of dyes obtained from natural sources with a mixture of mineral salts to give a claimed permanent hair colouration affect. The company uses “highly purified plant based dyes” with the trade mark of RBE-Colors. These dyes include:
l Lawsonia inermis
l Indigofera tinctoria ext
l Curcuma longa root ext
l Rubia cordofolia root ext
l CI58000 from Rubia tinctorium root ext
l CI73015 from Indigofera tinctoria ext
l Beetroot ext
l Quercetin
l Rutin
l Haematoxylon campechianum wood ext
l Haematoxylum braziletto ext
l Astaxanthin
l Crocetin (CI75100)
l CI 75810 from Chlorophyllin-Copper complex
l Iron-Chlorophyllin complex
l Annatto (CI75120)
l Gardenia jasmenoides fruit ext
l Emblica officinalis fruit ext
l Saffron crocus ext
The mineral salts include a complex mixture of the magnesium, calcium, ferrous, copper, zinc compounds with gluconate, aspartate and citrate in various combinations. The technology is described in more detail in a series of patent applications; eg US7550014 (B2) and WO2007130777 (A2).
The dyes and mineral salts are packaged separately in aqueous solutions and are mixed together just before use. The metals act as a mordant which helps to hold the dyes on the hair and give a claimed permanent colouring effect against shampooing. The colour solution may contain citric acid and lactic acid so the final colouring solution may be at quite low pH values.
Mordanting of dyes in this way can work in one or, in a combination of, two ways. Firstly the positively charged metal ions are capable of interacting quite strongly with the hair. This is especially true for copper and more so in damaged hair which has a higher negative charge than undamaged hair. The metal ions can then interact (ie form complexes with) the aromatic plant hair dye molecules, thus locking them to the hair. Whether this effect occurs at the hair surface or within the hair will depend to some extent on the size of the dye molecule and the strength of the hair/metal ion/dye interaction. The stronger the interaction the more likely the dye complex is to be held close to the surface of the hair.
If the metal ion/dye complex is particularly strong then a water insoluble complex may be formed. This is probably occurring to some extent as the two product solutions have to be fixed just prior to use. The coloured insoluble complex is then precipitated on and around the surface of the hair. A further function of the metal ions in this system may be to modify the colour of the plant dye.
BARRIERS TO DEVELOPMENT
So we have a new approach to permanent hair colouring that does not use the well known synthetic dyes which have been the cause of so much discussion over the years. But is this product going to be legal for sale in the EU?
At the present time there is no positive list for hair dyes in the EU and none of the dyes listed above are in Annex 2 of the Cosmetics Directive (ie none are banned). The supplier simply has to have a safety assessment undertaken by an appropriately qualified person and if this determines the product to be safe for cosmetic use then all is satisfactory.
However, only three of the dyes used are currently on the list of 117 supported dyes within the EU. This means that when a positive list is imposed the product will become illegal unless the defined set of safety tests are undertaken on all the materials defined as hair dyes. The results would then be presented to the EU Commission in the form of a dossier and a favourable opinion would need to be given. Once this (favourable) opinion is given the dye may pass into the land of approved materials.
There is a view that natural/plant derived materials are somewhat safer than their synthetic counterparts. But this cannot be true as many natural materials make very good poisons; and as we know, the poison is in the dose.
This situation raises interesting points. The Cosmetics Directive/Regulation is meant to be the guardian of all that is safe, however it also acts as a very significant barrier to both innovation and the replacement of current, less than ideal materials with new ones whether they are natural or synthetic.
The cost of bringing a new material into the EU cosmetics market is very high so this area is really only available to the large multinational companies, leaving smaller and potentially more innovative players trailing in their wake. So it could be said that the regulatory situation at present will perpetuate the use of less than ideal materials whilst suppressing their possible replacements.
EU REGULATIONS AFFECTING HAIR DYES
l All cosmetics are controlled in the EU by the Cosmetics Directive, soon to become a Regulation. This change will occur in a few years and exactly what this means will not become clear until after the EU comes back from its extended summer holiday. By the time you read this there is a chance that the new Regulation will have been published in the Official Journal.
l The Cosmetics Directive envisaged (in 1976) a positive list for hair dyes. This has yet to come about so it cannot be that urgent.
l Some hair dye materials are partially regulated in the EU firstly by inclusion in Annex 2 of the Directive, ie some dyes are banned. Others are included in Annex 3 part 1 (eg PPD and PTD). This restricts the use of the material to colouring the hair and defines maximum levels and warnings etc. Others are in Annex 3 part 2 which is a provisional restricted list with a time limit. Materials here are awaiting an eventual move to part 1 or Annex 2.
l Thus any non-regulated material could currently be used to colour the hair if the user has assessed it to be safe. This is an overriding requirement of the Directive for all cosmetic products as even formulations which only contain approved materials may not be safe to use.
l In its move towards a positive list the EU Commission has produced a list of 117 supported hair dyes and this is available on its website (http://ec.europa.eu/enterprise/
cosmetics/doc/hd_updated_safety_file_submitted_117.pdf). This was last updated in November 2006, so nothing new has been added to this list in the last three years.
l The EU Commission required that industry, mainly through EU cosmetics trade organisation Colipa produced safety dossiers for all materials on this list. In effect this means that the safety of hair dyes and the data to support this is only provided by the largest multinational cosmetics companies.
l These dossiers are passed to the SCCS (Scientific Committee for Consumer Safety, an expert committee previously called the SCCP and before that the SCCNFP) for evaluation.
l The SCCS then comes up with an opinion on the dossier and thus the safety of the material which is published on another part of the Commission website (http://ec.europa.eu/health/ph_risk/committees/04_sccp/sccp_opinions_en.htm).
l Following this opinion the material may either get passed to DG Enterprise for regulation via the Annexes in the Directive or more data may be requested.
l Once the Directive becomes a Regulation this situation changes somewhat as hair dyes will be included in Annex 4 which currently covers cosmetic colourants, ie anything coloured which isn’t a hair dye. However, this list may not become a positive list when the regulation is created as there still seems to be a clause allowing “for all data to be collected”.
To use a hair dye in the EU a safety dossier needs to be produced. The contents of this safety dossier are defined closely by the expert committee and this creation can be an expensive exercise. It follows that any material intended to be used to colour the hair (natural or synthetic) must pass through this process.