Researchers from the University of Copenhagen in Denmark instructed 80 overweight and obese men and women to eat a very low-calorie diet—812 calories per day—for the first four weeks. For the next eight weeks, scientists randomly gave 23 participants a placebo, while the remaining 57 participants took a combination of supplements divided into three separate doses per day that totaled 2,000 mg of calcium, 1,500 mg of green tea extract, 1,218 mg of L-tyrosine, 302 mg of caffeine and 1.2 mg of capsaicin. This was a double-blind study, meaning scientists did not know which participants received the treatment or placebo.On the first and last day participants took the supplements, doctors measured the calorie burning (thermogenic) effect of the treatment, as well as blood pressure, heart rate, body weight and body fat. During the initial four-week low-calorie diet, participants lost an average of 15 pounds of body weight. On the first day of treatment, those who had taken the supplement combination burned 21 more calories after four hours of being awake but at rest (resting metabolic rate) than did those who had taken the placebo. After eight weeks, those who had taken the thermogenic supplements continued to burn 20 more calories during four hours at rest and had lost an average of two pounds more body fat, compared to placebo. Blood pressure and heart rate did not change in the thermogenic treatment group, leading researchers to conclude that this combination of supplements may help dieters safely maintain lower weight after a low-calorie diet. Doctors noted that previous studies have linked thermogenesis to the active ingredient in green tea—an antioxidant known as a catechin—and to capsaicin.