Survey of Chemical Substances in Consumer Products, No. 86 2007 – Survey and risk assessment of chemical substances in deodorants

Survey and risk assessment of chemical substances in deodorants

6 Discussion

Deodorants are associated with an increased risk of skin allergy as a consequence of their contents and use pattern related to especially, allergenic fragrance substances but also in some cases preservatives. In the present investigation labelling of the most sold deodorants on the Danish market was checked, followed by the analysis of selected products and a risk assessment of selected substances.

Ninety seven deodorants, considered to be the most sold on the Danish market, were purchased, of these, nine products were not declared to contain perfume, while ”perfume” was declared on 17 products but without naming any individual fragrance substance.

On the basis of the labelling of the contents on the purchased deodorants, 23 products were selected for the analysis of the content of 26 fragrance substances, and 15 deodorants were selected for the determination of triclosan content. The products for the analyses were selected such that exposure to the fragrance substances cinnamyl alcohol, farnesol, hydroxycitronellal, isoeugenol, HICC and isoeugenol could be estimated. The fragrance substances to be included in the risk assessment were selected on the basis that these were frequent/potent allergens and a dose-response study of persons allergic to the respective substance was available. This was the case for cinnemal, hydroxycitronellal, HICC and isoeugenol (7-10). Cinnamyl alcohol can transform in the skin to cinnamal and was also chosen for the quantitative analysis to illustrate potential cinnamal exposure. Farnesol has been identified as an important allergen in deodorants (61). It was therefore selected to get an overview of the exposure from this substance.

According to the labelling of the products, 65.9% of the deodorants contained one or more of the fragrance allergens, which were selected for the study. The 26 fragrance substances, which should be declared when used in cosmetics, include allergens which differes in potency and incidence of allergy. The most allergenic and frequent allergens are 14 fragrance substances, which are used for the screening of perfume allergy, i.e. the ingredients of fragrance mix I and fragrance mix II. However even with in this group there is a difference in allergenic properties of the individual substances. In addition the substance methyl heptin carbonate is very potent allergen (28), and oxidation products of d-limonene and linalool are frequent allergens (63, 64). Evernia furfuracea extract (tree moss), which is among the 26 fragrance substance, has been shown to be a very common allergen (62). These important allergens were present in 1.1%-65.9% of the products (Table 4). The most potent allergens, cinnamal, methyl 2-octynoate and evernia prunastri extract were present in realtively few products. Evernia Prunastri extract contains some of the most potent allergens ever identified: chloroatranol and atranol (65, 66). The EU Commission’s Scientific Committee SCCP, has recommended that these substances should not be present in cosmetic products due to their allergenic properties (67). In the present investigation, evernia prunastri extract was present in four products, and although their content in the products is not quantified, it is not appropriate.

Although there is a great difference in the allergenic potency and use concentration of the individual fragrance substances, even potent allergens are used in several products and in combination with other allergens. Several substances are structurally similar and they will contribute additionally to the risk of allergy, when they are used simultaneously. The influence of a high allergen load on the risk of allergy is not known, but simultaneous exposure to several allergens in allergic individuals can give synergistic reactions (69).

Among the fragrance substances selected for risk assessment, hydroxyisohexyl 3-cyclohexene carboxaldehyd (HICC) was declared on 33 % of the products, hydroxycitronellal on 27.3 %, isoeugenol on 9.1 %, and cinnamal on 1.1 % of the deodorants. In an investigation from 1996, HICC was found in 53 % of 73 deodorants, hydroxycitronellal in 50 %, isoeugenol in 29 %, and cinnamal in 17 % (6). Obviously, there appears to be a decline in the use of these substances. However, both local and international products from five European countries were included in the first investigation. Furthermore, in the previous investigation, the content of the fragrance allergens was determined by chemical analysis, while in the present investigation the frequency was based on the information from the labelling on the products. In addition, there is an administrative limit of 10 ppm, under which the regulated fragrance substances need not be labelled. Thus, alone on this basis, the results of the two investigations may come out differently and cannot be compared. Thus it is not possible to conclude that use pattern of these fragrance allergens has changed over time.

The risk assessment was based on investigations employing persons with allergy to the respective substances, as it is known that limit values derived from such data are very effective in prevention of new cases of allergy as well as in limiting the consequences of the disease in persons who have aquired allergy (27). From the studies on HICC-allergic persons, the acceptable concentration of this substance in deodorant will be under 200 ppm (7); the exact limit could not be established in the study. Among the 23 products selected for chemical analysis, 17 of which were declared to contain HICC, six products were found to contain more than 200 ppm HICC. This means that 1/3 of the products containing HICC, corresponding to 6.8% of the 88 perfumed deodorants included in the present study, did not comply with the recommendation made by SCCP. The HICC content in one deodorant was 4431 ppm, i.e. more than 20 fold the above mentioned limit and more than twice the maximum concentration found in the earlier deodorant investigation performed 10 years back (6).

Perfume industry’s organisation IFRA has decided that 15.000 ppm is the limit value for HICC to limit the risk of allergy. The scientific basis for the limit value is not available in the open scientific literature. It has been proposed that HICC should not be present in deodorants because of allergy risk (7). HICC was present in 33% of the deodorants on the Danish market.

From the studies on hydrocycitronellal allergic persons, the acceptable limit of hydroxycitronellal in deodorants would be under 320 ppm (8); the precise limit could not be established in the study. The chemical analysis of 23 selected deodorants revealed that six products contained 320 ppm or more hydroxycitronellal. This means that hydroxycitronellal in at least 6.8% of the 88 perfumed deodorants in the present study was 320 ppm or more, maximum 1746 ppm. This level of hydroxycitronellal is higher than the the maximum hydroxycitronellal, i.e. 1023 ppm found in deodorants in the previous study, 10 years back (6). Perfume industry’s organisation IFRA has set 10.000 ppm as limit value for hydroxycitronellal to limit the risk of allergy. The scientific basis for the limit value is not available in the open scientific literature.

From the studies on isoeugenol-allergic persons, the acceptable concentration of isoeugenol in deodorants will be under 63 ppm (10); the precise limit could not be set in the study. The chemical analysis of 23 selected deodorants revealed that the concentration of isoeugenol in three of the products was 63 ppm or more. This means that at least 3.4% of the 88 deodorants in the present study contained 63 ppm or more isoeugenol, maximum 138 ppm, which is lower than the maximum concentration (458 ppm), found in deodorants 10 years back (6).

Perfume industry’s organisation IFRA has set 200 ppm as acceptable limit for isoeugenol to limit the risk of allergy. The scientific basis for the limit value is not available in the open scientific literature, but this limit value is not far from the above mention 63 ppm. In the mean time, the lower limit (200 ppm) has not resulted in lower incidence of isoeugenol allergy, which is possibly due to the use of substances structurally related to isoeugenol (47, 48).

From the studies on cinnamal allergic persons, the acceptable concentration of cinnamal in deodorants will be under 100 ppm (9); the precise limit could not be established in the study. The chemical analysis of the 23 selected products revealed that one product contained 5 ppm cinnamal, which is not considered to be of any risk. Perfume industry’s organisation IFRA has set 500 ppm as acceptable limit for cinnamal to limit the risk of allergy. The scientific basis for the limit value is not available in the open scientific literature. Cinnamyl alcohol can transform to cinnamal in the skin (52-55), so that animals sensitised to one of these substances reacted to the other substance (52). Simultaneous reactions of these two substances in humans have also often been observed (56). Cinnamy alcohol should be included in the risk assessment of cinnamal. Cinnamy alcohol was determined in 23 selected deodorants in the present study.

Farnesol was present in 14.8 % of the investigated products. The chemical analysis of 23 selected products revealed 9-1791 ppm farnesol in these products. A dose-response study on farnesol allergic persons has not yet been performed; therefore, it is not possible to perform risk assessment of farnesol exposure.

Perfume industry has from summer 2007 introduced an 1100 ppm limit for the use of farnesol. In the present study, only two deodorants contained farnesol over this limit. Thus, in present situation, the proposed limit will not affect the Danish market or incidence of farnesol allergy. This limit should be validated in the studies employing farnesol allergic persons.

The preservative triclosan was found in 15 products in concentrations from 480 ppm to 2400 ppm and was present mainly in expensive deodorants. Triclosan is an allergen, the frequency of allergy is not yet mapped, but is considered to be lower than for several other preservatives, for example methylchloroisothiazolinone/methylisothiazolinone (80). A dose-response study of allergenic effect of triclosan has not yet been performed, and therefore, it is not possible to perform a risk assessment.

Analyses of fragrance substances in the 23 selected deodorants revealed that labelling of the products with respect to the content of these substances complied with the guidelines in the Cosmetic Directive. None of the limits set by the perfume industry’s organisation IFRA were violated. There are no adopted/ implemented limits in EU for permitted concentrations of the selected fragrance substances, and thus neither in Danish Statutory Order on Cosmetics.

It can be concluded that fragrance substances, which are both potent allergens and frequent causes of allergy in cosmetic users, are present in deodorants. The most potent fragrance allergens are also used the least. The allergens are often present in combination, and the allergen load in these products is considerable. The deodorants contain fragrance substances, which SCCP has evaluated and recommended should not be present in cosmetics. In some products the concentrations of certain fragrance substances were at levels, which are considered to cause a not insignificant risk of allergy. All products complied with the existing legislation.

Fragrance substances are among the most frequent causes of allergy. Deodorants are associated with an increased risk of development of skin allergy because of the exposure conditions in the armpit. The use of allergenic fragrance substances in deodorants is an area, where an effort to prevent fragrance allergy will be advantageous.