Written by Slawomir (“Swavak”) Gromadzki, MPH

Garcinia Cambogia (Garcinia gummi-gutta), also known as the Malabar tamarind, is a tropical fruit grown in Southeast Asia, India and Africa. Garcinia cambogia extract is a very popular and widely known weight loss supplement, often praised by celebrity TV personality Dr. Oz.

The key active ingredient in Garcinia cambogia is Hydroxycitric acid (HCA) and its lactone responsible for weight loss, appetite reduction, and blocking fat accumulation (>, >). HCA can also be found in supplements made from the plant Hibiscus subdariffa.

Garcinia Cambogia bears a small fruit, reminiscent of a pumpkin in appearance, which has been traditionally used to reduce appetite and treat obesity, digestive and bowel problems, intestinal parasites, and arthritis.


The health benefits of Garcinia cambogia may include the following:

  • Increased fat and carbohydrate metabolism
  • Reduced body weight
  • Reduction & regulation of appetite
  • Reduced cravings for sugary and other unhealthy foods
  • Improved mood and cognition
  • Diuretic effect (increased elimination of excess body fluids)
  • Increased energy
  • Balanced blood glucose levels
  • Improved bowel movements
  • Lowered cholesterol and triglyceride levels
  • Prevention of kidney stones
  • Reduced joint inflammation and pain
  • Increased ability to fight cancer
  • Prevention of ulcer
  • Antibacterial properties


Garcinia Cambodia is especially famous for its ability to aid weight loss, as it naturally contains an active component called Hydroxycitric acid (HCA), which is known to reduce fat synthesis and help suppress appetite.

Research suggests that HCA works by blocking a certain enzyme called adenosine triphosphate-citrate-lyase, which contributes to the formation of fat cells.

HCA has a chemical structure very similar to that of citric acid which is the primary acid in citrus fruits. By inhibiting certain enzyme processes HCA reduces the conversion of sugar into fat thus preventing its accumulation in the body.

Scientific data show that HCA can reduce BMI and body weight, promote utilization of fatty acids as an energy source, suppress appetite, and increases serum serotonin and leptin levels helping to cope with emotional eating.

Several experiments on rats have demonstrated significant belly fat reduction, weight loss, and lowered blood glucose levels (>, >, >).

Although some studies have demonstrated that regular intake of Garcinia Cambogia extract may result in losing up to 5 kg (10 pounds) per month even if it is used without proper diet or exercise, yet the effect of HCA can be greatly enhanced when it is combined with a high-fibre and low-fat diet and regular energetic physical activity.

At least two studies reported a significant decrease in visceral fat, subcutaneous fat, and total body fat areas in the HCA group compared with placebo.

According to a 2015 scientific review of research on Garcinia cambogia, “Studies have shown that the extracts as well as the hydroxycitric acid (HCA), a main organic acid component of the fruit rind, exhibited anti-obesity activity including reduced food intake and body fat by regulating the serotonin levels related to satiety and increased fat oxidation… The extract from the plant also exerted hypolipidaemic (fats and cholesterol lowering), antidiabetic, anti-inflammatory, anticancer, antiparasitic, anticholinesterase (acetylcholine increasing) and hepatoprotective activities” (>).

Hydroxycitric acid contributes to weight loss (1) >

Hydroxycitric acid contributes to weight loss (2) >

Garcinia cambogia extract ameliorates visceral adiposity in mice fed on a high-fat diet >

Taking into consideration four relevant clinical human trials (>, >, >, >), the average weight loss as a result of taking Garcinia cambogia supplements (1.200-2.800mg per day, 50-60% HCA) was 3 pounds more than placebo.

The above chart reveals the results from the most relevant clinical studies, with subjects given Garcinia Cambogia (capsules with 50-60% HCA) or placebo over 8-12 weeks (>, >, >, >). The average weight loss for all these trials was 4.1 pounds vs 1.7 for those on Placebo. It should be noted that these studies used daily doses of between 1200mg to 2800mg, and that the higher the dose the more weight was lost compared to placebo.

In a 3-month study, Garcinia cambogia reduced body weight by about 3.7 kilos, in 89 mildly overweight adults (>). In another 3-month trial it reduced weight in 20 obese adults by 3.5 kilos, of which 85% was fat (>).


Garcinia cambogia extract (HCA) can help lower appetite by increasing production of the neurotransmitter and antidepressant serotonin, which apart from being associated with calm and happy feelings, is also known to regulate appetite, reducing unhealthy cravings and desire for comfort foods (>, >, >, >, >, >, >, >, >).

Since Garcinia cambogia leads to increased availability of serotonin which helps suppress appetite, it should be regarded as one of the mechanisms contributing to the weight loss effect of G. cambogia in humans.


Garcinia cambogia extract helps remove calcium oxalate kidney stones in both genetic and non-genetic Drosophila models of nephrolithiasis (>).


Animal studies show Garcinia cambogia may also help increase energy expenditure (>).

In a 5-day experiment of 6 male athletes, hydroxycitric acid from Garcinia cambogia increased fat breakdown and decreased carbohydrates breakdown, thus helping boost endurance performance through sparing sugar reserves (>).

In another experiment, the use of Garcinia cambogia produced similar results. It again increased fat breakdown and decreased carbohydrates breakdown, enhancing exercise performance in six female participants (>).


Garcinia cambogia helps lower high cholesterol and high triglyceride (another bad fat) levels. It also helps raise the beneficial HDL cholesterol (>, >, >, >, >).


Garcinia cambogia may help reduce insulin resistance and supports healthy blood sugar levels by encouraging body cells to increase the uptake of sugar (glucose) from the blood and use it to produce energy (>, >, >).

Raspberry ketone and Garcinia Cambogia rebalanced disrupted insulin resistance and leptin signalling in rats fed high fat fructose diet >


In rats with colitis (gut inflammation), Garcinia cambogia extract reduced inflammation by blocking the production of inflammatory enzymes and molecules (>).

In mice with multiple sclerosis, hydroxycitric acid lowered inflammation, decreased the nerve damage, and increased the levels of most powerful antioxidant enzymes (superoxide dismutase &glutathione reductase) (>).


In a cell study, Garcinia cambogia active ingredients garcinol, guttiferone K, and hydroxycitric acid blocked tumor growth and killed lung & colon cancer (>, >, >), xanthones killed breast, stomach, mouth, blood, and lung cancer (>), and garcinol blocked cancer proliferation in breast, colon, oesophageal, lung, liver, brain, blood, kidney, pancreas, prostate cancers (>, >).


In obese rats, HCA (Garcinia cambogia extract) protected liver, kidneys, and brain by reduced oxidative damage (>, >, >, >).


According to a rat study, Garcinia cambogia may lower stomach acidity when it is too high and helps prevent damage to the stomach lining, supporting recovery from ulcers (>, >).


HCA has been shown to block the growth of Staphylococcus aureus (causing skin and airway infections), Escherichia coli (gut infection), Klebsiella pneumoniae (lung infection, pneumonia), Pseudomonas aeruginosa (, urinary, and blood infections), and Bacillus subtilis (gut infection) (>, >).


In an animal study, the Garcinia cambogia extract produced a diuretic effect increasing the elimination of excess fluids (water), which in fact, could be another factor that may contribute to its weight-reducing effect (>).


In mice, bioflavonoid ingredients found in Garcinia cambogia killed the Plasmodium parasite (cause of malaria), increasing the survival rates (>, >).


Surfing internet in order to find information about Garcinia cambogia we find many articles suggesting that although some studies using HCA have produced amazing weight loss results,  others showed the supplement had little to no effect.

However, when we try to investigate the reliability of those articles we find out that they are based on biased studies funded by pharmaceutical companies that want to undermine competitive products such as Garcinia cambogia.

For example, the 2013 meta-review (>) that examined existing clinical studies on Garcinia cambogia was funded by GlaxoSmithKline, the manufacturer of the prescription weight loss drug Orlistat (Alli), which is expensive and causes side effects!

It is even more interesting that also the academic editor for the mentioned above meta analysis was the lead author for studies that showed positive results for Orlistat (>, >, >) and at the same time he was the lead author for the studies that found Garcinia cambogia to be ineffective!

It is therefore not surprising that the studies and research on Garcinia cambogia paid by a pharmaceutical company which manufactures a slimming drug finds mixed results on the effects of Garcinia Cambogia.

In 2012, it was revealed that CNN medical contributor Dr. Drew Pinsky was paid by GlaxoSmithKline (the same which sponsored negative studies on Garcinia cambogia) to encourage the off-label use of the antidepressant Wellbutrin by saying on-air that the drug helped women achieve more orgasms during intercourse. (source >)


Normal use of HCA supplements shouldn’t cause any harmful side effects. However, as it is true with many other good natural remedies and nutritional supplements, taking higher doses may in rare cases lead to some gastro-intestinal problems.

According to a 2015 scientific overview of Garcinia cambogia, “Although the possible toxicity associated with the regular use of HCA has raised concerns, in most cases, complaints have been related to multicomponent formulations and at this stage G. cambogia has not been confirmed as the potentially toxic culprit” (>).

A 2011 meta-analysis > which examined all published research on Garcinia Cambogia, concluded that it is safe and free from any major side effects when taken at dosages up to 2800 mg (60% HCA) per day .

Some studies suggest that using large doses of Garcinia cambogia for a long time may be harmful to the liver and may cause other side effects (>, >, >, >). However, taking into consideration the mentioned above proof according to which some studies on Garcinia cambogia were funded by pharmaceutical companies, it is difficult to say if these results are reliable.

In addition, there are many other studies which demonstrated that Garcinia cambogia is safe and free from bad side effects (>).

Due to the lack of sufficient scientific data, Garcinia cambogia is not recommended to be used during pregnancy and breastfeeding.


Garcinia cambogia is not recommended to be used by individuals who are on medications that help control asthma, allergies, diabetes, cholesterol (statins, etc.), blood thinning (warfarin, etc.), and mental disorders like anxiety or depression.


Studies on Garcinia cambogia usually used doses of one to about three grams per day for over two to twelve weeks.

With regards to supplements containing HTC from Garcinia cambogia, typical recommended dose is usually about 500mg to 1000mg (minimum 50% HCA) taken two to not more than three times daily 30-60 minutes before meals with a glass of water or herbal tea.


It is advisable to start from smaller dose such as about 500 mg per day, then increase to 1000 mg per day after a week or so, and to not more than 2500 mg after another week.

It is better to not take Garcinia cambogia continuously for a very long time. Stop taking it after every week for 1-2 days; after every month for a week; and after every three months take one month break. You can also use it alternatively with other safe herbal remedies and nutritional supplements that help loose weight or reduce appetite:

To get better results make sure to find a supplement which contains Garcinia Cambogia Fruit Extract which is standardised to contain minimum 50% HCA.

Unfortunately, many Garcinia cambogia formulas contain only a fraction of HCA active ingredient to keep costs down, but the effectiveness is very low.


There are people who claim to boost weight loss by using a combination of Garcinia cambogia supplements together with organic apple cider vinegar (with mother). They usually mix two tablespoons of apple cider vinegar in a glass of warm water and drink it together with two capsules of Garcinia cambogia extract (minimum 50% HCA) one to two times a day.


Overweight and Obesity >

Appetite Control >



– Downs, B.W., Bagchi, M., Subbaraju, G.V., et al (2005) Bioefficacy of a novel calcium-potassium salt of hydroxycitric acid. Mutat Res. 2005 Nov 11;579(1-2):149-62.

– Ohia, S.E., Opere, C.A., LeDay, A.M., et al (2002) Safety and mechanism of appetite suppression by a novel hydroxycitric acid extract (HCA-SX). Mol Cell Biochem. 2002 Sep; 238(1-2): 89-103.

– Roongpisuthipong, C., Kantawan, R., Roongpisuthipong, W. (2007) Reduction of adipose tissue and body weight: effect of water soluble calcium hydroxycitrate in Garcinia atroviridis on the short term treatment of obese women in Thailand. Asia Pac J Clin Nutr. 2007; 16(1): 25-9.

– Preussa, H.G., Bagchib, D., Bagchi, M., et al (2004) Efficacy of a novel, natural extract of hydroxycitric acid (HCA-SX) and a combination of (…) in weight management in human volunteers. Nutrition Research Volume 24, Issue 1, January 2004.

– Preuss, H.G., Garis, R.I., Bramble, J.D., et al (2005) Efficacy of a novel calcium/potassium salt of hydroxycitric acid in weight control. Int J Clin Pharmacol Res. 2005; 25(3): 133-44.


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