Study to Investigate the Effects of Different Doses of S-adenosyl-L-methionine (SAMe) in Subjects With Nonalcoholic Fatty Liver Disease and Non-treated Matched Healthy Volunteers as Control Group

Inclusion Criteria * Subjects with non-alcoholic steatohepatitis based on histology in medical history within the last 3 years * Subjects in a stable metabolic condition since histology for NASH (Non-alcoholic Steatohepatitis) Exclusion Criteria * Subjects with extrahepatic biliary obstruction * Subjects with primary sclerosing cholangitis (PSC) * Subjects with primary biliary cirrhosis (PBC) * Any form of malignancy within the past 5 years and/or basal cell carcinoma and squamous cell carcinoma of the skin within the past two years * History of active substance abuse (oral, inhaled or injected) within one year prior to the study * Subjects with renal impairment (creatinine level of \>2.0 mg/dL) * Subjects with a known hypersensitivity to the active substance (ademetionine) or methionine or to any of the inactive ingredients * Subjects with known genetic defects affecting the methionine cycle and/or causing homocystinuria and/or hyperhomocysteinemia (e.g., cystathionine beta-synthase deficiency, Vitamin B12 metabolism defect) * Subjects on total parenteral nutrition in the year prior to screening * Subjects after or planned for bariatric surgery (jejunoileal bypass or gastric weight loss surgery) * Extrahepatic cholestasis (proven by ultrasound) * Subjects with alanine aminotransferase (ALT) and/or aspartate aminotransferase (AST) \> 5 upper limit of normal (ULN) * Subject with serum total bilirubin (STB) \> 5 ULN * Subjects after liver transplantation and subjects on the waiting list for liver transplantation * Subjects with any of the following disease in medical history: * Viral hepatitis (serum positive HBcAb (hepatitis B core antibody) or Hepatitis C Virus (HCV) ribonucleic acid (RNA) * Evidence of autoimmune liver disease * Wilson's disease * Hemochromatosis * Alpha-1-antitrypsin deficiency * Known positivity for antibody to human immunodeficiency virus (HIV) * Known heart failure of New York heart Association class 3 or 4 * Current or history of significant alcohol consumption for a period of more than three consecutive months within five years prior to screening (significant alcohol consumption is defined as \> 3 U (unit)/day for men and \> 2 U/day for women, on average) or binge drinking or inability to reliably quantify alcohol consumption. * Clinical or histological evidence of cirrhosis F4 * Subjects with history of biliary diversion * Subjects with uncontrolled diabetes mellitus defined by HbA1c (hemoglobin A1c) \> 8.0 % at screening * Concomitant medication of B12, folate, betaine or choline * Concomitant treatment with glitazone within the past year prior to the study * Subjects with known folate or B12 deficiency * BMI (body mass index) \> 40 kg/m2 * History of major depression diagnostic and statistical manual of mental disorders (DSM-IV) or bipolar disease * Women of childbearing potential: positive urine pregnancy test during screening or unwillingness to use an effective form of birth control during the study. * Breastfeeding women * Any condition that, in the opinion of the investigator, does not justify the patient's inclusion into the study * Investigational drug intake within one month prior to the study * Active, serious medical disease with likely life-expectancy less than five years * Uncooperative attitude or reasonable likelihood for non-compliance with the protocol or any other reason that, in the investigator's opinion, prohibits the inclusion of the subject into the study * Legal incapacity or limited legal capacity, or who are incarcerated. * Inability to return for scheduled visits. * Inability to understand and follow the requirements of the protocol in the local language