HCA (hydroxycitric acid) is a close relative of citric acid, the agent that gives citrus fruits their characteristic tart flavor. HCA is obtained as a 50% standardized extract of Garcinia cambogia, a small fruit from southern India, where it has been used for centuries as a food preservative, flavoring agent, and digestive aid. HCA is a safe, natural supplement for weight management. When calorie intake exceeds the body's energy needs, the excess glucose is converted into glycogen, which is stored in the liver and muscles for future conversion into energy. Weight gain occurs after the body's capacity for glycogen storage is reached. At this point, glucose from excessive calorie intake is converted into acetyl coenzyme A via a metabolic pathway involving the enzyme ATP-citrate lyase and then into fat molecules, which are stored in fat cells. HCA is a competitive inhibitor of ATP citrate lyase, a key enzyme which facilitates the synthesis of fatty acids, cholesterol and triglycerides. HCA may reduce the synthesis of fatty acids in humans during a persistent excess of energy intake as carbohydrate. It has been suggested that HCA promotes weight loss by increasing serotonin levels, reducing hunger and appetite, and suppressing carbohydrate conversion into fat by inhibiting ATP-citrate lyase, thus regulating fat and obesity related genes. HCA may also attenuate the increases in oxidative stress, and insulin resistance. Supplement to be taken in conjunction with a healthy diet and regular exercise program. Results may vary.