The purpose of this study was to determine the prevalence of the use of dietary supplements among the young people exercising in fitness rooms in Kraków and environs. In this study, 81 % of the population used some form of dietary supplement; nutritional supplements were used by 21% of women and 60 % of men, and were used most frequently by young people 21-25 years of age. The most popular supplement s were creatine, (20%) and HMB- beta-hydroxy-betamethylbutyrate (19%). Only 14% of the respondents asked for the opinion of qualified personnel, such as doctors, pharmacists or dieticians.