Garcinia cambogia is caffeine free, according to ConsumerLab's report. The laboratory testing report, which can be seen on Doctor Oz, mentions how Garcinia cambogia's primary ingredient is HCA.
Though the report also shows contents such as lead, arsenic, mercury and cadmium, they are in negligible quantity, as stated in the report. HCA, which stands for hydroxycitric acid, is Garcinia cambogia's key active ingredient that is instrumental in weight loss based on studies done on human beings and animals, as stated by WebMD. Findings show that it suppresses a person's appetite, hinders the lipogenesis process and aids in lipid oxidation, resulting in gradual weight loss. Details of clinical trials on human beings and animals, which show these findings, are mentioned on Drugs.com.