Garcinia Cambogia Extract (HCA)

Garcinia Cambogia is a type of fruit native to Indonesia, Asia, and Africa. Traditionally, it has been used to make different foods such as curry and soup.  From this fruit, HCA (hydroxycitric acid) is extracted. HCA is believed to suppress hunger and produce weight loss when taken as a dietary supplement.

Garcinia Cambogia is a very popular supplement that people take for a variety of reasons such as menstruation problems, edema, removing parasites in the intestines, rheumatism and constipation. Recently Dr. Oz mentioned Garcinia Cambogia Extract (GCE) on his TV show claiming its “the holy grail of weight loss.”

How does HCA produce weight loss?

HCA inhibits an enzyme in our bodies named citrate lyase. This enzyme is responsible for converting carbohydrates into fatty acids, cholesterol, and triglycerides. HCA also has the ability to suppress hunger. HCA can also increase serotonin levels in the brain. Serotonin is a neurotransmitter strongly associated with depression. Increasing serotonin levels is believed to improve mood and decrease emotional eating.


There’s lots of scientific research on Garcinia Cambogia. Some evidence suggests that it may be effective for weight loss and as an appetite suppressant, other evidence is inconclusive. Lets look at some of the articles.

Mol Cell Biochem 2002 Sep;238(1-2):89-103.

Safety and mechanism of appetite suppression by a novel hydroxycitric acid extract (HCA-SX).

In a previous article it was shown that in the rat brain cortex a novel HCA extract (HCA-SX, Super CitriMax) increases the release/availability of radiolabeled 5-hydroxytryptamine or serotonin ([3H]-5-HT), a neurotransmitter implicated in the regulation of eating behavior and appetite control.

The aim of the present study was 2-fold: (a) to determine the effect of HCA-SX on 5-HT uptake in rat brain cortex in vitro; and (b) to evaluate the safety of HCA-SX in vivo.

Conclusions: HCA is a safe supplement, lethal dose in rats is greater than 5,000mg/kg. HCA also increased the levels of serotonin in the brain which may be beneficial in appetite control, depression, insomnia, migraine, among other serotonin deficient conditions.

Diabetes Obes Metabol. 2004 May;6(3):171-80.

Effects of a natural extract of (-)-hydroxycitric acid (HCA-SX) and a combination of HCA-SX plus niacin-bound chromium and Gymnema sylvestre extract on weight loss.

HCA-SX has been shown to reduce appetite, inhibit fat synthesis and decrease body weight without stimulating the central nervous system.

Hydroxycitric acid (HCA-SX) alone and in combination with niacin-bound chromium (NBC) and a standardized Gymnema sylvestre extract (GSE) on weight loss in moderately obese subjects was evaluated by monitoring changes in body weight, body mass index (BMI), appetite, lipid profiles, serum leptin and excretion of urinary fat metabolites.

A randomized, double-blind, placebo-controlled human study was conducted in Elluru, India for 8 weeks in 60 moderately obese subjects (ages 21-50, BMI >26 kg/m(2)). Subjects were randomly divided into three groups. Group A was administered HCA-SX 4667 mg, group B was administered a combination of HCA-SX 4667 mg, NBC 4 mg and GSE 400 mg, while group C was given placebo daily.

Results: At the end of 8 weeks, body weight and BMI decreased by 5-6% in both groups A and B. Food intake, total cholesterol, low-density lipoproteins, triglycerides and serum leptin levels were significantly reduced in both groups. A non-significant effect was observed in all parameters in group C.

 J Med. 2004;35(1-6):33-48.

An overview of the safety and efficacy of a novel, natural(-)-hydroxycitric acid extract (HCA-SX) for weight management.

 This study was a 90-day toxicity study. The dose dependant effects of HCA-SX were assessed on body weight, selected organ weights, hepatic and testicular lipid peroxidation and DNA fragmentation, hematology and clinical chemistry, and histopathology in male and female Sprague-Dawley rats. No toxicity was found after this trial.

Furthermore, clinical studies to evaluate the safety and efficacy of HCA-SX over a period of eight weeks were conducted in 60 human volunteers. Subjects were given a 2,000 kcal diet/day, participated in a 30 min walking exercise program 5 days/week and given an oral dose of placebo or 4666.7 mg HCA-SX (providing 2,800 mg HCA) in three equally divided doses 30-60 min before meals, Body weight, BMI, lipid profiles, serum leptin, serotonin and excretion of urinary fat metabolites were determined at 0, 4 and 8 weeks of treatment. At the end of 8 weeks, body weight and BMI decreased by 5.4% and 5.2%, respectively. Food intake, total cholesterol, LDL, triglycerides and serum leptin levels were significantly reduced, while HDL and serotonin levels, and excretion of urinary fat metabolites (a biomarker of fat oxidation) significantly increased. No significant adverse effects were reported.

Results: These results demonstrate the safety, bioavailability and efficacy of HCA-SX in weight management.

 Physiol Behav. 2000 Oct 1-15;71(1-2):87-94.

Effects of (-)-hydroxycitric acid on appetitive variables.

 Eighty-nine mildly overweight females were prescribed 5020-kJ diets for 12 weeks as part of a double-blind, placebo-controlled parallel group study. Forty-two participants ingested 400-mg caplets of Garcinia cambogia 30-60 min prior to meals for a total dose of 2.4 g/day. Forty-seven participants ingested matched placebos. Weight and body composition were assessed at baseline and every other week for 12 weeks. Both groups lost body weight with the active group achieving a significantly greater reduction (3. 7+/-3.1 kg versus 2.4+/-2.9 kg).

JAMA. 1998 Nov 11;280(18):1596-600.

Garcinia cambogia (hydroxycitric acid) as a potential antiobesity agent: a randomized controlled trial.

The objective of the present study was to evaluate the efficacy of G Cambogia for body weight and fat mass loss in overweight human subjects. 12 week randomized, double-blind, placebo-controlled trial. Subjects received either 1500 mg of hydroxycitric acid per day or placebo and were assigned to a high fiber, low energy diet.

Results: A total of 135 subjects were included in the study. Both the active group, and placebo group lost significant amounts of weight over the 12 week period. However, between-group weight loss differences were not statistically significant. The active group lost 3.2kg vs 4.1kg. (p=0.14).

Conclusions: Garcinia Cambogia failed to produce significant weight loss and body fat loss beyond that observed with placebo.

Safety and Dose

 This product has been around for many years and has been consumed in foods without known side effects. Although there are reports about apparent hepatotoxicity (liver damage) associated with the use of Garcinia Cambogia (HCA), there are no reports in any of the clinical trials performed. There has been extensive research done on the safety of HCA both in humans and rats. Its worth mentioning that none of the clinical trials to date have reported any serious side effects or modifications in lab test values. It is logical to think that these hepatotoxicity reports are associated with the use of supplements that contain HCA and other ingredients. Some supplements can contain over 20 ingredients and have been associated with liver damage. The use of Garcinia Cambogia (HCA) alone has not been found to be hepatotoxic.

A study performed at Creighton University in 2002 reported that HCA is a safe product to use and found the lethal dose in rats was greater than 5,000mg/kg. This gives this supplement a very wide safety margin.

I would not recommend taking this product for longer than 3 months since there is little information regarding its safety after long periods of consumption.

Avoid taking this or any other supplement if you are pregnant or breastfeeding. Furthermore, this product has not been properly evaluated in children and should be avoided.

The appropriate dose for adults varies from 500mg to 1,000mg before meals. Take no more than 2,500mg per day.


 The interesting thing about Garcinia Cambogia Extract (HCA) is how contradictory results are between clinical trials. There are studies that show significant weight loss and body fat loss, others show no significant differences. It’s difficult for me to recommend this product without clear and conclusive evidence that can be repeated over and over again.

One thing worth mentioning is the known association between HCA and Citrate Lyase enzyme inhibition, which leads to a decreased production of fatty acids. Another known effect is its ability to maintain increased serotonin levels in the brain, similar to how antidepressants act. These effects are well known and have been clearly demonstrated.

Bottom line, there is plenty of evidence that shows HCA to be effective for both weight loss and appetite suppression. HCA is considered a safe supplement when taken within the recommended doses.  I believe this product can be effective for certain individuals who wish to loose weight, especially when associated with an energy restrictive diet and an exercise program. My only concern comes from the small amount of evidence which was inconclusive.

Questions and answers

 How much weight can I expect to loose with Garcinia Cambogia?

Expect to loose between 6 – 12 pounds after a 3 month period. Those who associate diet and exercise regimes can loose up to 3 pounds a week.

What dose should I take of Garcinia Cambogia?

Dose varies from 500mg – 1,000mg before each meal. Maximum daily recommended dose is 3,000mg. I recommended taking no more than 2,500mg per day.

Is Garcinia Cambogia safe?

Garcinia Cambogia is considered safe when taken for no longer than 12 weeks and within the daily recommended dose.

Hepatotoxicity has been reported, although toxicity studies have not reported this finding.