Hydroxycitric Acid (Garcinia Cambogia)

Research Findings

Hydroxycitric acid (HCA) has received some favourable research results of late, however in the not so distant past, research has found conflicting results when testing its effects on weight loss, effects on satiety, energy intake and fat burning properties.

The extract is used in two forms, calcium/potassium salt HCA, or calcium based HCA. The calcium/potassium hydroxycitric acid is reportedly more readily absorbed into the body. The extract can be found commonly in popular fat burners such as the stacker2.

Research Title:

Safety assessment of (-)-hydroxycitric acid and Super CitriMax, a novel calcium/potassium salt.

Year Published: 2004

Research Summary:

The authors reviewed research completed on CitriMax, a popular fat burner containing 50% hydroxycitric acid as calcium salt to find out the safety of taking such a supplement. In several clinical trials when up to 2800 mg per day of HCA were consumed, no significant adverse effects were reported. These trials included data taken from both human and animal trials. The authors concluded that hydroxycitric acid is safe for human consumption.

National Library of Medicine:

Soni MG, Burdock GA, Preuss HG, Stohs SJ, Ohia SE, Bagchi D. Safety assessment of (-)-hydroxycitric acid and Super CitriMax, a novel calcium/potassium salt. Food Chem Toxicol. 2004 Sep;42(9):1513-29. Abstract

Research Title:

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.

Year Published: 2004

Research Summary:

Researchers in India at the Georgetown University Medical Center tested HCA alone and HCA combined with niacin (from the B vitamin group - is known to have cholesterol lowering properties) bound chromium and a standardised Gymnema extract (known to suppress sweet tastes - often used in the treatment of diabetes) and tested the effect of a placebo treatment.

Moderately obese subjects were evaluated for changes in body weight, body mass index (BMI), appetite, lipid profiles, serum leptin and excretion of urinary fat metabolites,while taking one of these three treatments. At the end of eight weeks of treatment, subjects were tested in the above areas, and researchers found that in both the HCA group and the HCA combined with the niacin bound chromium group and gymnema body weight and body mass index decreased by 5 - 6%. There were also significant improvements in food intake, total cholesterol, low-density lipoproteins, triglycerides and serum leptin for both groups.

The study showed that improvements were greater when the HCA was taken in combination witht he niacin based chromium and the gymnema. This study was conducted under standard double-blind, placebo controlled conditions.

National Library of Medicine:

Preuss HG, Bagchi D, Bagchi M, Rao CV, Dey DK, Satyanarayana S. 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. Diabetes Obes Metab. 2004 May;6(3):171-80. Abstract

Research Title:

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

Year Published: 1998

Research Summary:

Researchers wanted to evaluate the efficacy of hydroxycitric acid as a tool to fight obesity and conducted a twelve week double blind, placebo controlled trial with 135 overweight men and women within a weight control research unit. Participants were either given 1500 mg of HCA per day or a placebo and both groups kept to a high fiber low energy diet regime. Body mass index and fat mass measures were taken before the trial began and after twelve weeks. Researchers found that there were no differences between the group who were given the HCA and those that received the placebo.

National Library of Medicine:

Heymsfield SB, Allison DB, Vasselli JR, Pietrobelli A, Greenfield D, Nunez C. Garcinia cambogia (hydroxycitric acid) as a potential antiobesity agent: a randomized controlled trial. JAMA. 1998 Nov 11;280(18):1596-600. Abstract

Research Title:

Effects of 2-week ingestion of (-)-hydroxycitrate and (-)-hydroxycitrate combined with medium-chain triglycerides on satiety and food intake.

Year Published: 2001

Research Summary:

7 Male and 14 Female moderately overweight participants were either given 500 mg of HCA or 500 mg combined hydroxycitrate with 3 g medium chain triglyercides. Participants also chose their own meals, with four isoenergetic drinks. The study was conducted over two weeks and found that both groups lost body weight but there was no significant difference between the two groups. There were no significant differences between the groups when energy intake was assessed on a 24 hourly basis and reported satiety levels were the same across the groups.

National Library of Medicine:

Kovacs EM, Westerterp-Plantenga MS, de Vries M, Brouns F, Saris WH. Effects of 2-week ingestion of (-)-hydroxycitrate and (-)-hydroxycitrate combined with medium-chain triglycerides on satiety and food intake. Physiol Behav. 2001 Nov-Dec;74(4-5):543-9. Abstract

Conclusions about Hydroxycitric Acid (Garcinia Cambogia):

As you can see the conclusions made by researchers looking at the effects of hydroxycitric acid or HCA seem to conflict with each other. It is clear that the use of the supplement is safe for human consumption even at very high dosages, however is it really a supplement that can help with weight loss and fat burning ? While past data has dismissed the supplement as being ineffective, more recent research completed just this year supports its use as a weight loss supplement.

The key to looking at these research outcomes is to assess the way in which this research was conducted. Research conducted with a small amount of participants for a shorter amount of time will return less accurate results than those completed over a longer amount of time and with larger amounts of participants. The research cited above published in 2001 by the Physiological Behavior Journal used only 21 participants over 2 weeks. This really isn't a long enough time to assess the interaction of a supplement within the human body. A longer trial may return different results, it may not, however it is something to keep in mind when assessing the applicability of these results.

Also some research uses measures such as body mass index, which is a crude predictor of body fat. While others use measures such as serum leptin levels and excretion of urinary fat metabolites, which determine whether fat is actually being lost. The more types of measures that are used, the more accurate the overall findings will be.

The study conducted this year in India used measures for body mass index, appetite, lipid profiles, serum leptin and excretion of urinary fat metabolites, while the study completed in 1998 used only the body mass index and proportion of fat mass. I am inclined to take the study incorporating more direct measures of the effect of hydroxycitric acid as more accurate.

Also the study completed in 1998 also incorporated a high fiber low energy diet with the testing of hydroxycitric acid finding that it had little effect on weight loss, energy intake or satiety, while the more recent study found that when hydroxycitric acid was taken alone significant weight loss was induced. This may demonstrate that hydroxycitric acid can have a similar effect as going on a healthy diet, but as the point was made in the article link below, may demonstrate that the supplement may have benefit for those that have already lost weight and want to maintain it.

In conclusion, the research does support the reasonable use of hydroxycitric acid in weight loss supplements, however, you can replicate the same effect of using hydroxycitric acid in putting yourself on a healthy diet. Depending on your own personality - this supplement may be useful if you are a binge eater or emotional eater or just can't seem to stick to a set diet.

Other references you might be interested in:

Quackwatch Hydroxycitrate as a Weight-Loss Ingredient

Top of Hydroxycitric Acid Page

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