Survey of Chemical Substances in Consumer Products, 53 – Survey of chemical substances in dandruff shampoo

Survey of chemical substances in dandruff shampoo

Summary and conclusion

Twelve different dandruff shampoos were collected for this project in order to identify their ingredients via the product declarations.

An initial overview of legislation pertaining to dandruff shampoo revealed that a distinction is made between, on the one hand, medical use of dandruff shampoo, and on the other hand, cosmetic use of dandruff shampoo. Dandruff shampoo for medical use is regulated by "bekendtgørelsen om mærkning m.m. af lægemidler" (Statutory Order on labelling etc. of drugs), whereas dandruff shampoo for cosmetic use is regulated by the Statutory Order on cosmetic products.

The main part of this report is a systematic outline of the ingredients found in the products. It appears from this outline that the 12 products together include 115 different substances, responsible for one or several of 14 randomly listed functions (solvents, surface active agents, emulsifiers, preservatives etc.)

On the basis of enterprise patent descriptions, the likely expected concentration intervals for the substances in the different categories of function were examined.

The following list represents a conclusive summary of the concentration intervals and the systematic categorization:

1.	Solvents	(1 substance)	60 – 85 %
2.	Surface active agents (surfactants) Anionic Amphoteric Non-ionic	(23 substances)	12 – 30 % 1 – 8 % 1 – 8 %
3.	Emulsion stabiliser	( 6 substances)	0.5 – 1 %
4.	Fragrances (perfumes)		0.5 – 1 %
5.	Emulsifiers	(24 substances)	0.4 – 4 %
6.	Anti-dandruff agents	(7 substances)	0.3 – 2 %
7.	Thickening agents and viscosity controlling agents (gelation agents)	(9 substances)	0.25 – 1.3 %
8.	Softeners (emollients)	(9 substances)	0.2 – 3 %
9.	Buffers	(5 substances)	0.1 – 1 %
10.	Film formers and hair-care agents	(7 substances)	0.1 – 1 %
11.	Soothing, skin-conditioning and astringent substances	(13 substances)	0.1 – 0.7 %
12.	Preservatives and anti-microbial agents	(21 substances)	0.05 – 0.5 %
13.	Colourants	(6 substances)	0.001 – 0.007 %
14.	Humectants	(2 substances)	not found
15.	Other substances	(4 substances)	varying

In order to identify other substances typical in dandruff shampoo which do not have direct anti-dandruff effects, the 12 dandruff shampoos were compared to 14 ordinary shampoos previously surveyed by the Danish EPA (Danish EPA, extracts from database - 2002).

The study indicated that in addition to active dandruff agents, dandruff shampoo contains more lipophile and lipophile-like substances than ordinary shampoo.

Finally, an exposure scenario for use of dandruff shampoo was established on the basis of e.g. EU risk assessment reports.

This scenario led to the following expression of skin exposure per incident where X represents the ingredient component stated in percentage of weight:

Hands: 12 g * (X/100) / 420 cm² = 0.29 * X mg/cm²_{dermal surface}/day

Scalp: 12 g * (X/100) / 1200 cm² = 0.1 * X mg/cm²_{dermal surface}/day

EU's Scientific Committee on Cosmetic Products and Non-food Products intended for Consumers (SCCNFP) has prepared guidelines for testing cosmetic ingredients in safety evaluation. These guidelines include the following exposure scenario:

One hair-wash requires 8 grams of shampoo. It is assumed the hair is washed daily. Since the shampoo is applied to wet hair and skin, it is assumed that approximately 1 per cent of the shampoo applied will be absorbed. This means that with a content of X (calculated in weight percentage) exposure is:

8 gram/day * 0.01 * X = X * 0.08 g/day

Due to insufficient data, environmental exposure was limited to an expected approximate 100 per cent discharge of the dandruff shampoo to the aquatic environment.