Survey of chemical substances in consumer products, 72 – Assessment of DHA in self-tanning creams applied in spray booths

Assessment of DHA in self-tanning creams applied in spray booths

1 Introduction

Self-tanning products have existed for many years as lotions to be rubbed onto the skin. In recent years a new development has taken place in that since 1999 (1) there have been booths on the market in which self-tanning products are more or less automatically sprayed onto the customer's body. The purpose of the booths is to achieve a more even covering of the self-tanning product than through manual application. The customer is usually in the booth for automatic application for between 6 and 60 seconds. Time spent in booths for manual application using a turbine spray is longer, typically from 2-3 minutes.

There are many different types of self-tanning product on the market. The products typically contain dihydroxyacetone as the tanning agent. Dihydroxyacetone (DHA) is the only self-tanning agent the FDA (US Food and Drug Administration) has authorised in self-tanning products (1). DHA reacts with amino acids in the outer layer of the skin and gives the skin a brownish hue. The effect appears after 2-6 hours. Isolated cases of allergies have been described, but in most cases, these are believed to be due to other contents than DHA. Formation of aerosols cannot be avoided during application in booths. Exposure to the substances in self-tanning liquids used in booths occurs through skin contact, inhalation, and through contact with the eyes and the mucus membranes. There is also a risk that aerosols could be spread outside the booth.

Cosmetic products must not pose a threat to the safety or health of the user when they are used. The Danish Consumer Council therefore contacted the Danish Environmental Protection Agency (Danish EPA) to have any risks from the products assessed. The Danish Toxicology Centre (DTC, a unit of DHI Water & Environment) agreed with the Danish EPA to review a number of representative self-tanning products and techniques on the Danish market in order to achieve an overview of exposure and any health risks from inhaling the products, or contact with the eyes or mucus membranes. DTC has also carried out a comprehensive review of the literature, searched the Internet, and contacted manufacturers and suppliers of self-tanning products and booths, in order to obtain data on DHA.

The National Environmental Research Institute of Denmark (NERI) has conducted measurements during use of three different types of spray booth: manual turbine application with a spray gun (air brush), a closed 3rd generation booth, and an open 4th generation booth. Furthermore, background measurements were taken in the room outside the booths in order to assess any exposures for salon staff.

The study has revealed that many different application techniques are used when spraying on self-tanner in booths and salons, and these techniques are regularly being improved. The study has focussed on the three latest techniques on the market. These techniques are today not the most commonly used, but they are expected to win increasing market shares over the coming years. The three techniques included in the study are estimated by the manufacturers to account for 20 per cent of the market, while the traditional manual air-brush technique accounts for the remaining 80 per cent. Today there is not sufficient knowledge of the health effects of DHA and the project focused on the techniques expected to be used in the future, so that future health assessments in the area can reflect relevant and actual exposure scenarios as far as possible.

Two self-tanning salons have contributed with technical information, demonstrations and meetings, and they have made booths available for the NERI measurements.