Naturally toxic: natural substances used in personal care products

Background: Nature offers an incredible diversity of chemical compounds that boast a wide array of physiological effects. Many natural substances are employed in personal care products. Which of these natural substances are hazardous ingredients? How do European legal instruments regulate natural substances with toxic effects? Results: 1,358 natural substances appear in the ‘International Nomenclature of Cosmetic Ingredients’ (INCI list, ‘inventory ...... of ingredients employed in cosmetic products’) [Commission Decision 96/335/EC], most of them are herbal products, others are of animal, fungal, or bacterial origin. Out of these, 655 natural substances are enrolled in the EU database for classification and labeling, with 56% classified as hazardous chemicals, 38% classified due to their hazards to human health (35% due to their effects on skin and eyes), and 21% due to their hazards to the environment. 53 natural substances in the INCI list are classified as carcinogens, mutagens, and substances toxic to reproduction. Many classifications are not in line with expectations from experience, such as severe classifications of substances derived from some basic food plants or lacking classification of known medical plants or plants with sensitizing potential. Classification and labeling is a trigger for the registration requirements according to REACH. It must be assumed that there are more substances that should undergo the REACH process among the 703 natural substances that do not turn up in the C&L inventory. Conclusions: Many natural substances used in personal care products have toxic properties. The interdisciplinary compilation and analysis of regulatory instruments concerning natural substances revealed some inconsistencies which need further analysis and urgent correction to ensure prudent handling in consumer products.