Hydroxycitric acid, commonly known as HCA, is a compound frequently found in dietary supplements marketed for weight management. It has drawn attention for its purported effects on body weight and fat accumulation. Originating from certain tropical plants, it is often featured in supplements for weight loss.
What is Hydroxycitrate
Hydroxycitrate is a chemical compound derived from citric acid, the primary acid in citrus fruits. It is predominantly extracted from the rind of the Garcinia cambogia fruit, a small, pumpkin-shaped fruit native to Southeast Asia, including India. Other Garcinia species, such as Garcinia indica and Garcinia atroviridis, also contain HCA. Its unique chemical structure, which includes an additional hydroxyl group compared to citric acid, is believed to contribute to its biological activity. Its presence in these fruits led to its widespread popularity as a dietary supplement ingredient.
How Hydroxycitrate Influences Metabolism
Hydroxycitrate is thought to influence metabolism primarily by inhibiting the enzyme ATP citrate lyase. This enzyme plays a role in converting citrate into acetyl-CoA and oxaloacetate, which are precursors for fatty acid and cholesterol synthesis in the body. By blocking ATP citrate lyase, HCA may reduce the production of new fats from carbohydrates, a process known as lipogenesis.
Beyond its effects on fat synthesis, HCA is also suggested to influence appetite. Some research, particularly in animal studies, indicates that HCA may increase levels of serotonin in the brain. Serotonin is a neurotransmitter that helps regulate feelings of fullness and satiety. An increase in serotonin levels could potentially lead to reduced food intake, further contributing to its proposed role in weight management.
Evidence for Weight Management
Scientific research into hydroxycitrate’s effectiveness for weight loss in humans has yielded mixed results. Some studies have reported modest reductions in body weight and fat mass. For example, a meta-analysis indicated a small, statistically significant difference in weight loss favoring HCA over a placebo, with an average reduction of approximately 0.88 kg (about 1.94 pounds). Other studies have observed reductions in de novo lipogenesis, the process of converting carbohydrates into fat, in individuals overfed with carbohydrates.
However, a number of other human clinical trials have found no significant weight loss or fat mass reduction attributed to HCA supplementation, beyond what might be observed with a placebo. Some studies have been criticized for factors that could affect HCA absorption, such as the inclusion of high-fiber diets. The overall scientific consensus on HCA’s efficacy for weight management remains inconsistent, with the magnitude of any observed effects often being small and their clinical relevance uncertain.
Safety Considerations and Side Effects
Hydroxycitrate is generally considered possibly safe for most individuals when taken orally for periods of 12 weeks or less. Reported side effects are typically mild and may include digestive upset, such as nausea, stomach discomfort, or diarrhea. Headaches, dry mouth, and allergic reactions have also been noted. In rare instances, more serious adverse effects like liver injury have been reported in connection with supplements containing HCA or Garcinia cambogia extracts.
Certain populations should exercise caution or avoid HCA supplementation:
Pregnant or breastfeeding individuals due to insufficient safety data.
Individuals with bleeding disorders, as HCA might slow blood clotting.
Diabetics, who should monitor blood sugar closely as HCA may reduce levels, potentially requiring medication adjustments.
Those with liver problems or depression, due to concerns about potential liver toxicity and interactions with medications like SSRIs or MAOIs.