The study may help companies manufacturing and marketing the products by providing further clinical evidence of the ingredient’s effectiveness in the fast growing and valuable skin lightening and brightening market, which is particularly important throughout the Asian region.
Glutathione is a tripletide consisting of cysteine, glycine and glutamate, which combines to primarily function as an antioxidant.
Proving oxidized glutathione’s skin whitening potential
Glutathione is known to have a skin-whitening effect in humans through its tryosinase inhibitory activity, but the effects on the skin of oxidized glutathione were yet to be assessed before this clinical trial took place.
The trial was commissioned by Japan-based Kyowa Hakko, which is one of the world’s major manufacturers of oxidized glutathione, an ingredient that has previously been shown to reduce ageing effects caused by overexposure to radiation.
It was published in an article published in the peer reviewed journal, Clinical, Cosmetic and Investigational Dermatology.
“Thirty healthy women, age 30 to 50, applied a lotion containing Kyowa’s Oxidized Glutathione (GSSG) to one side of their face for 10 weeks. A placebo was applied to the other side. Researchers found that skin treated with the 2% Kyowa oxidized glutathione location had significant whitening over the placebo group,” said Ryusuke Nakagiri, senior director of Strategic Science at Kyowa Hakko USA.
Overall improvement in skin condition
The trial assessed changes in melanin index values, moisture content of the stratum corneum, smoothness, wrinkle formation and elasticity of the skin.
As well as the whitening effect, the study indicated that the ingredient served to increase the moisture content of the stratum corneum, suppress wrinkle formation and help to improve skin smoothness, serving to improve the overall condition of the skin.
Kyowa’s oxidized glutathione is also said to be aqueous stable, does not break down in light and heat and is ultimately designed for use in personal care products worldwide.