Hydroxycitric acid (HCA), a derivative of citric acid, is found primarily in a small, sweet, purple fruit called the Malabar tamarind or, as it is most commonly called, Garcinia cambogia . Test tube and animal research suggests that HCA may be helpful in weight loss because of its effects on metabolism. However, studies in humans have found mixed results.

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Sources

HCA is not an essential nutrient. The Malabar tamarind is the only practical source of this supplement.

Therapeutic Dosages

A typical dosage of HCA is 250 to 1,000 mg 3 times daily. Supplements are available in many forms, including tablets, capsules, powders, and even snack bars. Products are often labeled Garcinia cambogia and standardized to contain a fixed percentage of HCA. Various proprietary forms of HCA are also available, often claimed by their promoters to be more effective.

Therapeutic Uses

Although animal]]> and ]]>test tube studies]]> as well as two human trials suggest that HCA might encourage ]]>weight loss]]> , other studies have found no benefit. ]]>1-14,20,21]]>

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What Is the Scientific Evidence for Hydroxycitric Acid?

It remains unclear whether HCA offers any weight-loss benefits.

In an 8-week double-blind, placebo-controlled trial]]> of 60 overweight individuals, use of HCA at a dose of 440 mg 3 times daily produced significant weight loss as compared to placebo. ]]>15]]>

In contrast, a 12-week, double-blind, placebo-controlled trial of 135 overweight individuals, who were given either placebo or 500 mg of HCA (as Garcinia cambogia extract standardized to contain 50% HCA) 3 times daily, found no effect on body weight or fat mass. ]]>16]]> However, this study has been criticized for using a high-fiber diet, which is thought to impair HCA absorption. ]]>17]]>

A 12-week double-blind trial of 89 individuals found that HCA had no effect on appetite. ]]>18]]> Another study tested HCA to see if it could cause weight loss by altering metabolism, but no effects on metabolism were found. ]]>19]]>

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Safety Issues

The Malabar tamarind (from which HCA is extracted) is a traditional food and flavoring in Southeast Asia. No serious side effects have been reported from animal or human studies involving either fruit extracts or the concentrated chemical. A proprietary calcium-potassium salt of HCA appears to have undergone considerable formal safety study, without evidence of toxicity appearing. 20]]> However, maximum safe doses have not been established, especially for pregnant or nursing women, young children, or people with severe liver or kidney disease.