February 1, 2005

The Cause of Unpleasant Odor During Use of SingleComponent Hair Bleach Explained
To be Implemented in Hair Bleach Products for Men in Spring 2005
Mandom Corporation (Headquarters: Osaka; President Executive Officer: Motonobu Nishimura) has discovered, forthe first time in this industry, that the odor-causing substance in single-component bleach is pyruvic acid and has
developed a method to reduce this odor.
The company plans to announce the results of its research alongside its research partner, Takasago InternationalCorporation, at the Seventh Asian Society of Cosmetic Scientists Conference held in Thailand (Bangkok) between
March 7-9.
<What is Single-Component Hair Bleach?>
It would be no exaggeration to state that hair coloring has become part of our daily lives and the tools to do so havebecome essential style products. Hair bleach decolorizes hair by causing the oxidative degradation of melanin; it isa basic hair coloring product that lifts hair color. Hair bleach comes in various types—each of which has its own use.
The most common type of hair bleach is multi-component bleach, which requires that several compounds are mixed
before use. This type of product can lift hair color in a short period of time.
In contrast, single-component hair bleach, which does not require mixing, lifts the hair in a gentler manner thanmulti-component bleach. As a result, it is easier the degree of decolorization; single-component bleach is a usefulproduct for gradually lifting one’s hair color. Thus, single-component hair bleach is a popular product among first-timeusers of hair bleach and individuals who do not wish to significantly decolorize their hair.
<Explanation of the Unpleasant Odor of Single-Component Bleach>
Despite its convenience, one drawback of single-component bleach is the unpleasant, sharp odor that is produced
during its use. Because of this odor, many individuals choose not to use it.
We discovered that this odor is produced by the skin on users’ hands (when they touch hair during application) andscalp coming into contact with the liquid product. The specific cause for this is a reaction between pyruvate—
an important intermediary compound produced in biological metabolic pathways like the glycolysis system and thecitric acid cycle—and hydrogen peroxide—the active ingredient in hair bleach products. This reaction produces acetic
acid (vinegar) on the surface of the skin, which creates the sharp, unpleasant odor smelled by users.
<Fragrances Effective at Masking this Vinegar Odor>
After screening multiple fragrance compounds for their ability to mask this vinegar odor, we identified a few typesof compounds as particularly effective.
The single-component hair bleach “Gatsby Honnori Bleach (Non-Medicinal Product)” that will go on saleFebruary 8 2005, will contain a fragrance product composed of several of these compounds, including dihydromyrcenol,B-ionone, and α-methylbenzyl acetate. These compounds successfully control the unpleasant odor experienced during
use of single-component bleaches. We have applied to patent this technology with our research partner, Takasago
International Corporation.
END
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