Idiosyncratic drug induced liver injury (DILI) is an unpredictable reaction of exposed individual on a certain drug, and the drug-induced autoimmune hepatitis (DIAIH) presents a DILI phenotype that mimics idiopathic autoimmune hepatitis (AIH) when considering the clinical, biochemical, serological and histological parameters. We present a case of a 48-year-old male that was hospitalized due to severe hepatocellular liver injury two months after the self-treatment with the muscle-building dietary supplement based on arginine-alpha-ketoglutarate, L-citrulline, L tyrosine, creatine malate and beet extract. His immunology panel was positive with increased IgG levels, and the radiologic methods showed no signs of chronic liver disease. He underwent corticosteroid treatment with adequate response. After the therapy withdrawal, a clinical relapse occurred. Seven months after the initial presentation liver MR suggested the initial cirrhotic changes of the right liver lobe. Liver biopsy revealed abundant lymphoplasmacytic infiltrate with piecemeal necrosis and grade 2 fibrosis. He responded well on the corticosteroid treatment again, and was further treated with low dose prednisone without additional relapses. Several years later, further management confirmed presence of liver cirrhosis with no histological or biochemical signs of the disease activity. DIAIH is a DILI phenotype difficult to distinguish from idiopathic AIH despite a wide armamentarium of diagnostic methods. Regular patient monitoring and clinical open-mindedness with the adjustment of therapeutic approaches according to the disease course are more important than strict labelling of the disease.