STEFAN BÄNZIGER*¹, BARBARA OBERMAYER¹, BRIGIT SUTER¹, MARIETTA SEIFERT²,
THOMAS HERRLING², KATINKA JUNG²*
* Corresponding authors
1. RAHN AG, Dörflistrasse 120, 8050 Zürich, Switzerland
2. Gematria Test Lab GmbH, Pestalozzistrasse 5-8, 13187 Berlin, Germany

Abstract

Naming something is a way of bringing it into focus and an important step towards understanding any phenomena. Here we coin the term Formul’Ageing. Every coin has two sides: on one side, the term Formul’Ageing refers to the ageing of the formulation (i.e., it refers to premature ageing of the formulation due to excessive radical formation inside the formulation upon e.g., exposure to the sun). The other side of the term Formula’Ageing could be summed up as formulation-provoked skin ageing. It hints at a yet under-recognised and indirect phenomenon: premature ageing of the skin resulting from the unexpected induction of free radicals inside the skin when basic formulations are topically applied and exposed to sunlight. However, in both cases of Formul’Ageing, free radical formation is thought to be the main underlying cause.
Using electron spin resonance spectroscopy, we found that a cosmetic antioxidative active ingredient provided stable and efficient protection against free radicals for cosmetic (sun care) formulations and, more importantly, the skin. Radical protection will help to assure efficacy and stability for the formulations and to counterbalance the collateral radical-promoting activity of most conventional formulations for the skin.

INTRODUCTION

Reactive oxygen species (ROS) can be harmful to both skin and cosmetic formulations.
In the skin, excessive ROS can randomly damage lipids, proteins and DNA and are thought to be the main driver of premature (skin)ageing, photo-ageing, wrinkling, and pigmentation (1-4). Normally, the skin’s antioxidant defence system can defend it against ROS damage with its antioxidant defence enzymes, such as catalases, and non-enzymatic small molecule antioxidants, such as ascorbic acid, tocopherols, and glutathione. However, that system can easily be overloaded, particularly by excessive UV(A) exposure. Older skin is even more susceptible to ROS overload because the activity of the antioxidant defence enzymes and the level of nonenzymic antioxidants decrease with age (5).
In cosmetic formulations, excessive ROS are probably not toxic to the consumer. Radicals formed in the product are unlikely to penetrate into the living layers of the skin and do harm (6). However, excessive ROS formation may accelerate the degradation of the functional ingredients and provoke physiochemical destabilisation and unpleasant olfactory s ...