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. Laboratory and animal studies of HCA have produced results that indicate a potential for modulation of lipid metabolism; consequently HCA is an ingredient in some weight loss products and dietary supplements. However, there is no clinical evidence that HCA has any benefit to humans in either of these applications.

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 caused potent testicular atrophy and toxicity.