KATINKA JUNG¹*, MARIETTA SEIFERT¹, THOMAS HERRLING¹, BRIGIT SUTER², BARBARA OBERMAYER², STEFAN BÄNZIGER²*
*Corresponding authors
1. Gematria Test Lab GmbH, Pestalozzistrasse 5-8, 13187 Berlin, Germany
2. RAHN AG, Dörflistrasse 120, 8050 Zürich, Switzerland

Abstract

Modern, multifunctional cosmetic products are increasingly complex and confront the cosmetic industry with new problems in product development. UV filters, anti-oxidative ingredients and particularly basic raw materials may increase the burden of free radicals in the formulations and/or inside the skin, even though they were designed to do just the opposite. First, protecting the formulation from free radicals is pivotal for proper product function and stability. For example, the ingredients cannot act as photosensitizers and must neutralize UV-induced radical formation. By using electron spin resonance spectroscopy, we showed that a cosmetic active ingredient effectively quenched UV-induced radicals in skin- and sun-care formulations. Second, free radical protection of the skin is important to prevent premature skin-ageing. Surprisingly, many cosmetic raw materials, when applied to the skin and exposed to sunlight, provoke massive oxidative stress in the skin. Incorporation of cosmetic actives completely counterbalanced the raw material-induced oxidative stress in the skin. We conclude that the selective addition of appropriate cosmetic actives will help to guarantee that cosmetic products that are meant to do a good deed will indeed do so.

INTRODUCTION

The future belongs to multifunctional products
Educated consumers are increasingly aware that exposure to ultraviolet (UV) light promotes skin aging and cancer. However, manufacturers must look beyond just SPF and UVA to create multifunctional products that will attract consumers and convince them to buy and use the product regularly. In particular, there is a growing trend towards products that combine effective sun protection with skin care features, such as hydration, nourishment or radical scavenging.
Cosmetic actives provide opportunities for exciting new marketing concepts and claims that help a product to stand out from the crowd and gain market share. In addition, they will be increasingly important for enhancing the status of sun-care products. As a second line of biological defence, they prevent, reduce or repair the detrimental effects from UV overexposure, such as oxidative stress, DNA-damage, spot formation and erythema (1, 2).

Undesirable radicals within the formulation
To attract market attention, cosmetic products must cover more and more claims. Thus, the form ...