Abuse of anabolic androgenic steroids (AAS) is widespread in society and is today a major public health problem, associated with mental and somatic adverse effects and risk behavior, such as use of other illicit drugs and criminality. Testosterone, the most important endogenous male androgen, is therapeutically used in replacement therapy but is also extensively used as a doping agent. Traditionally, testosterone abuse is detected in urine in forensic cases and in serum in clinical diagnosis and monitoring, and free bioavailable serum testosterone is calculated by formulas. Salivary testosterone is however an attractive biomarker, as testosterone in saliva is supposed to reflect free testosterone in serum.