The supplement is made from garcinia cambogia, a fruit-bearing tree found in India and Southeast Asia. The fruit, which looks like a small pumpkin, has a rind containing hydroxycitric acid (HCA). This compound is purported to help suppress appetite and reduce body fat, although scientific evidence is lacking. (2) Hydroxycitric acid purportedly blocks an enzyme called adenosine triphosphate citrate lyase, which is important to making fat in the body, explains Steven Heymsfield, MD, professor in the laboratory of metabolism and body composition at the Pennington Biomedical Research Center at Louisiana State University in Baton Rouge. The supplement is also thought to boost levels of serotonin, a chemical in the body that acts as a neurotransmitter. Raising serotonin levels can suppress appetite, theoretically helping to reduce weight, says Haggans. Because supplements are not subject to federal approval before going to market, the U.S. Food and Drug Administration (FDA) has not determined whether garcinia cambogia is safe for consumption and whether the claims manufacturers make about it are true. (1) “There really aren’t any supplements proven to be a magic bullet for weight loss,” says Haggans. “In some cases, a supplement might make a tiny difference, but the evidence isn’t very strong.” People who take weight loss supplements are likely to be adhering to a healthy diet and exercising more, which make more of an impact on weight than the supplement itself. Overall, the research on garcinia cambogia is conflicting, says Dr. Rahnama. For example, a 2011 meta-analysis evaluated 12 randomized clinical trials of the supplement. (4) Researchers were able to assess data from nine of these studies and found that garcinia cambogia, taken in doses of 1,000 to 2,800 milligrams per day for two to 12 weeks, might help with short-term weight loss of about 2 pounds. In another review article published in 2013, scientists found that garcinia cambogia had little to no effect on weight loss. (5) The paper’s authors noted that larger and longer-term clinical trials are needed to reach any “definitive conclusions.” In other research from 2011, scientists gave people who were overweight either garcinia cambogia extract, soy leaf extract, which is another proposed weight loss supplement, or a placebo for 10 weeks. (7) Scientists found that none of the supplements helped participants lose weight or lower total cholesterol. Much of the research on blood sugar has been in mice, which while interesting, is preliminary evidence that requires further investigation and validation in humans, says Haggans. (8) Even data in humans can be conflicting, which is another reason more studies are needed, notes Rahnama. Reported side effects of garcinia cambogia are fairly mild and include headache, nausea, diarrhea, and upper respiratory symptoms like a stuffy nose, says Haggans. However, there have been case reports of the supplement being linked with mania, which can include symptoms such as decreased need for sleep, grandiosity, and rapid speech, she says, citing a 2016 paper. (10) Another concern is liver toxicity, which can be dangerous, says Susan L. Besser MD, a primary care provider specializing in family medicine with Mercy Personal Physicians at Overlea at Mercy Medical Center in Baltimore. In fact, according to two 2016 case reports, garcinia cambogia is associated with liver toxicity leading to liver transplantation. (11,12) Such side effects are concerning, but they require further investigation because case reports can’t prove cause and effect, says Haggans. Another concern to keep in mind is that garcinia cambogia might interact with some prescription drugs that raise serotonin levels, including antidepressants and opioid pain medication, because of the supplement’s impact on the neurotransmitter, says Haggans. “People think supplements are natural and therefore safe, but this isn’t necessarily true because they do have effects in the body and can interact with medication,” she says. Because supplements are not regulated, garcinia cambogia supplements may also contain additional ingredients, possibly contributing to adverse events. For example, in 2017 the FDA issued a warning to consumers telling them not to buy or use FrutaPlanta Life (Garcinia Cambogia Premium) because it contains sibutramine. (13) Sibutramine is a controlled substance removed from the market in 2010 because it can raise blood pressure and heart rate. The substance presents a risk for people with a history of coronary artery disease, congestive heart failure, abnormal heart rhythms, or stroke. The FDA also stated that FrutaPlanta Life might interact “in life-threatening ways” with medication. Dr. Besser also advises her patients to avoid garcinia cambogia in addition to other weight loss supplements. Most products come with instructions telling users to eat a calorie-restricted diet, “which is what causes the weight loss, not the pill,” she says. Rahnama has a more open view on the supplement. “When taken in small amounts, garcinia cambogia can potentially help facilitate the weight loss process,” she says. However, “it’s important to take it in conjunction with a diet and exercise regimen and to consider stopping the supplement if it does not help with progress.” If you’re thinking of taking garcinia cambogia or any other weight loss supplement, the bottom line is to talk to your healthcare provider, says Haggans. “If you’re trying to lose weight, you need a safe and healthy plan. Garcinia cambogia is not a magic bullet where you can eat all you want. It might make a tiny difference, but it’s not going to have a big effect on weight loss, and it has potential side effects.”
