Hydroxycitric acid

Hydroxycitric acid (HCA) is a derivative of citric acid that is found in a variety of tropical plants including Garcinia cambogia and Hibiscus subdariffa.

Biological effects
Laboratory and animal studies of HCA have produced results that indicate a potential for modulation of lipid metabolism. However, a clinical study has demonstrated that HCA has no effect in terms of weight loss or reduction of fat mass.

Chemical properties
One isomer of HCA, known as (2S,3R)-HCA, inhibits pancreatic alpha-amylase and intestinal alpha-glucosidase, leading to a reduction in carbohydrate metabolism in vitro. In a study in Zucker rats, which are genetically predisposed to obesity, Garcinia cambogia extract containing HCA showed that high doses led to significant suppression of epididymal fat accumulation, but also had high testicular toxicity. However, this study has been criticized because of possible contamination of the HCA used and various design flaws.