[Useful knowledge regarding tattoos]

The number of people with tattoos has continued to increase in recent years. In the USA about 23% and in Europe 9-12% of the population have tattoos. In the German media (2019) and by the infoportal Statista (2017), it is assumed that 21-25% of citizens have tattoos and that the trend is increasing (Statista 2018: 36%). Men and women wear tattoos equally. The age group 20-29 years dominates with almost 50% having tattoos. The following article describes the new regulations especially the REACH (Registration, Evaluation, Authorisation and Restriction of Chemicals) regulation, legal basis, and governmental controls on the subject of "tattoos". The composition of tattooing agents and testing options relevant for the user before and for the performance of tattooing are presented. Dermatologically associated diseases and testing procedures are listed. Since 70% of the population denies knowledge of this information even when they have tattoos themselves, this update is written as an overview for treating physicians and users.