The aim of this research is to measure caffeine levels in urine samples of random Syrian gymgoers, and to determine the paraxanthine/caffeine ratio as a mean to access CYP1A2 activity.

Urine samples were collected from 60 male clients in three different gymnasiums. All participants completed a detailed questionnaire about their lifestyle habits and medical history. Caffeine and paraxanthine were extracted from urine using solid-phase extraction (Strata C18), then analyzed by HPLC-UV (Knauer-Germany). Antipyrine was used as internal standard.

Most clients stated they consumed multiple cups of at least two different caffeinated drinks directly before going to the gym (coffee, tea, cola, energy drink). Caffeine concentrations in urine ranged between 2.5 and 34.23 mcg/mL. More than 60% of samples were above the 12 mcg/mL acceptable limit by the WADA/IOC. Paraxanthine concentrations in urine ranged between 1.124 and 29.141 mcg/mL. The paraxanthine to caffeine ratio was between 0.0673 and 1.869. The higher ratios were associated with taking three medications that affect CYP1A2 activity, such as ciprofloxcacin, alluporinol, rifampcin, mexitillin, or acyclovir. No correlation was found between paraxanthine/caffeine ratio, and smoking.

caffeine consumption is high among Syrian gymgoers, and its level in urine exceeded the recommended threshold of 12 mcg/mL. Although it is permitted by the WADA. The paraxanthine/caffeine ratio was in accordance with other published studies. CYP1A2 activity in participants may be affected by age, medications, or the presence of a liver or kidney disease.

In conclusion, caffeine intake should be monitored in gym clients, not only for doping issues, but also for health and safety concerns.