Update 1/2/20. Does Garcinia cambogia work? Well, if you saw the Dr. Oz show, you heard him say “it may be the simple solution you've been looking for to bust your body fat good.” He's also said Garcinia Cambogia was a “revolutionary fat buster” ―that requires no exercise, no diet, and, no effort. Those are very impressive words. But, does it have any side effects? It just might. I've been aware of this fruit and its alleged weight-loss benefits for many years but in case you have not, I wanted to review Garcinia Cambogia because there really is published research on this fruit. See the Supplements and Liver Failure Review too.
What Is Garcinia Cambogia?
Garcinia is a pumpkin-shaped fruit that grows in various regions of the world such as India, Asia, and Africa. Its scientific name is Garcinia gummi-guta although some may know it by its other more familiar name, Hydroxy Citric Acid (or HCA). Hydroxy citric acid is an ingredient in Garcinia Cambogia, found usually in the skin (rind) and fruit that is often said to be the active ingredient when it comes to weight loss.
What Does Garcinia Cambogia Do?
The main reason people take garcinia Cambogia is for weight loss. See the weight loss research below for more insights.
How Does Garcinia Cambogia Work?
The most popular theory is that the HCA compound in the fruit is said to work by blocking the conversion of carbohydrates into fat. By doing this, fat storage is reduced.
Others speculate that Garcinia can help weight loss is by decreasing appetite. This effect may be related to reports that it can increase serotonin, a chemical involved in reducing appetite. During the Dr. Oz segment, this was brought up as a potential benefit to “emotional eaters.” It could be that Garcinia works in all these ways and in other ways also.
Garcinia cambogia has been an ingredient in several products I've already reviewed including:
Read those reviews for additional information.
How To Recognize This Ingredient
In Supplements, Garcinia may be labeled as
- Garcinia cambogia
- Garcinia extract
- HCA extract
All these names mean the same thing.
Garcinia Cambogia Research
Let's look at the weight loss research on garcinia Cambogia. To keep things simple, let's focus mostly on human research.
Study. Oral hydroxycitrate supplementation enhances glycogen synthesis in exercised human skeletal muscle Here, 38 young men were given 500 mg of hydroxycitric acid (HCA) or a placebo along with with a high carbohydrate meal after exercise (60 minutes of cycling at 75% of maximum aerobic ability). Biopsies of the thigh muscle were taken immediately after exercise and 3 hours later.
Results. Men who received 500 mg of HCA had significantly lower levels of insulin. HCA also increased the formation of glycogen, the storage form of carbohydrates in the muscles.
Note. This study plus the 2007 rat study below, appear to lend believability to claims that Garcinia cambogia helps insulin resistance, and hence type II diabetes. This may be one of the reasons why Garcinia cambogia might be found in diabetes supplements such as Diab-X which I reviewed previously.
Study. Does Glycine max leaves or Garcinia Cambogia promote weight-loss or lower plasma cholesterol in overweight individuals: a randomized control trial . The study lasted 10 weeks and involved 68 overweight men and women who were broken into groups:
- Garcinia cambogia extract (2 grams per day)
- Glycine max leaf extract (soybean) 2 grams per day
Results: There were no significant differences between the groups in body weight or cholesterol levels.
Study. Super CitriMax (HCA-SX) attenuates increases in oxidative stress, inflammation, insulin resistance, and body weight in developing obese Zucker rats. As can be seen in the title, this was a rat study.
Results: Rats with type II diabetes that were given the HCA extract had reduced levels of C reactive protein (a sign of inflammation), glucose, insulin, and triglycerides. The rats also ate less food and had reduced body weight compared to rats getting the placebo.
Study. 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. This study involved 50 obese women (18-75 years of age) who were randomly split into 2 groups:
- Garcinia group
- Placebo group
Those getting Garcinia received 1.15 grams before meals, three times per day (3.45 grams total per day). All women were put on a 1000 calorie per day diet and tracked for 2 months.
Results: Women getting Garcinia atroviridis lost significantly more weight (6.1 lbs) than women who received the placebo (3 lbs).
Note. this study used Garcinia atroviridis which is a species related to Garcinia Cambogia.
Study. An overview of the safety and efficacy of a novel, natural(-)-hydroxycitric acid extract (HCA-SX) for weight management. This study involved both rats and humans. Let's just look at the human part of the study. This was an 8-week study that involved 60 people.
The people were given 2000 calories per day, walked 30 minutes a day, 5 days per week and were randomly given either a placebo or 4666.7 mg (about 4.7 grams ) of a supplement called Super CitriMax.
Results: At the end of the study, these results were observed in those who took Super CitriMax:
- 5.4% reduction in body weight
- 5.2% reduction in body mass index (BMI)
- Significantly decreased food intake
- Significantly decreased total cholesterol
- Significantly decreased LDL (bad cholesterol)
- Significantly increased HDL (good cholesterol)
- Significantly decreased triglycerides
- Significantly decreased leptin levels
- Significantly increased serotonin levels
Note. Leptin is a hormone made inside fat cells. Leptin plays a role in hunger.
Study. Effects of Garcinia cambogia (Hydroxycitric Acid) on Visceral Fat Accumulation: A Double-Blind, Randomized, Placebo-Controlled Trial. 39 overweight people (20-65 years of age) were given either a placebo or Garcinia cambogia for 12 weeks, along with a reduced-calorie diet (The men ate 2250 calories per day.
Women consumed 1800 calories per day). Those in the Garcinia group received a supplement that contained 1667 mg of Garcinia cambogia extract. This supplement contained 1000 mg of hydroxycitric acid (HCA is thought to be the active ingredient in Garcinia cambogia).
Results: Those taking the Garcinia extract lost significantly more abdominal fat and had more total fat loss, compared to those who received the placebo.
Study. The effect of (-)-hydroxycitrate on energy intake and satiety in overweight humans. This study lasted 2 weeks and involved 24 overweight people (12 men and 12 women). People were randomly split into groups that either received 900 mg of HCA or a placebo.The supplement containing the HCA was called Super CitraMax.
Results. Those who took HCA consumed fewer calories compared to those who received the placebo. This was deemed primarily to decreased snacking. No significant difference in body weight was seen.
Study. The effects of 2-week ingestion of (–)-hydroxycitrate and (–)-hydroxycitrate combined with medium-chain triglycerides on satiety, fat oxidation, energy expenditure and body weight. This investigation consisted of 11 overweight men and lasted 2 weeks. In the study, men consumed 3 meals and 4 same-calorie snacks a day. The men were randomly given:
- A placebo
- 500 mg HCA
- 500 mg HCA plus 3 grams of medium-chain triglycerides (MCT)
Results: everybody lost weigh (placebo too) but there were no significant differences between those getting the placebo and those getting HCA or HCA + medium-chain triglycerides.
Study . Effects of (-)-hydroxycitric acid on appetitive variables published the journal, Physiology, and Behavior. 89 overweight women were put on a low-calorie diet and randomly given either a placebo or 2.4 grams of Garcinia cambogia per day (this equaled 1.2 grams of HCA). The length of the study was 12 weeks (3 months).
Results. Those taking HCA supplements lost more weight (8 lbs) than those taking the placebo (5 lbs).
Study. titled (-)-Hydroxycitric acid does not affect energy expenditure and substrate oxidation in adult males in a post-absorptive state This study involved 10 overweight men who were given either a placebo or HCA (3 grams per day). The study lasted 3 days.
Results. No change in metabolic rate or fat burning.
Study. Garcinia cambogia (hydroxycitric acid) as a potential antiobesity agent: a randomized controlled trial . This study lasted 12 weeks and involved 135 obese men and women who were given either hydroxycitric acid (1500 mg per day) or a placebo, along with a high fiber, low-calorie diet (84 people completed the study).
Results. Both groups lost weight, (the placebo group lost a little more weight) but there were no significant differences in the weight loss between groups. So, according to this study, Garcinia cambogia did not work better than a placebo.
Summary Of Garcinia Research
Here's a quick breakdown of the studies summarized above:
- 2011 study: Human study. Garcinia didn't work. 2 grams per day used.
- 2007 study: Rat study. Garcinia worked.
- 2007 study: Human study. Garcinia worked. 3.45 grams per day used.
- 2004 study: Human /rat study. Garcinia worked. 4.7 grams per day used.
- 2003 study. Human study. Garcinia worked. 1667 mg per day/1000 mg HCA used.
- 2002 study: Human study. Garcinia didn't work. 900 mg HCA per day used.
- 2001 study: Human study. Garcinia didn't work. 500 mg HCA used.
- 2000 study: Human study. Garcinia worked. 2.4 g / 1.2 grams HCA used.
- 1999 study: Human study. Garcinia didn't work. 3 grams of HCA per day used.
- 1998 Study: Human study. Garcinia didn't work. 1500 mg of HCA per day used.
From this research, it appears 5 investigations noted Garcinia cambogia helped people lose weight. But, Just as many studies showed it didn't work. Those studies showing it worked also used a lower-calorie diet. In other words, you have to eat less. You can't just pop a pill.
Garcinia Cambogia And Cortisol
During the Dr. Oz show about garcinia, Dr. Julie Chen, who was featured in the segment, mentioned that garcinia helps to manage the stress hormone cortisol” which might help decrease belly fat. I searched the national library of medicine for
- Garcinia Cambogia cortisol
- HCA Cortisol
- hydroxy citric acid cortisol
I was not able to find any human studies showing changes in cortisol. In fact, in this 2008 study of a supplement containing HCA and L carnitine, no change in cortisol was seen.
Garcinia Cambogia Side Effects
For most people, the supplement is probably safe although in some people it may not be (see the liver failure section below.
Most studies don't last long. This makes it difficult to determine the side effects. The most common side effects reported include:
- GI problems
- Feelings of being nauseous
Here are some general thoughts. this list is not complete:
- Stop taking garcinia at least 2 weeks before having surgery
- Don't take if you are pregnant or breastfeeding
- Anyone under age 18
- Those taking diabetes medications like metformin, insulin, etc
- Speak to your doctor/pharmacist /dietitian if you take ANY prescription medications
- To reduce side effects, start with less than the recommended amount for the first week
People who take antidepressant medications should speak to their doctor before taking garcinia. There is some evidence that when combined with antidepressant medications (such as SSRIs), garcinia may make serotonin levels go too high. This is called serotonin syndrome can result in dangerously high blood pressure.
In a review of the safety, the author noted that most human studies involved small groups of people that were carried out over short periods of time.
Checking Amazon, those who rated it as 1 star, said supplements caused rapid heart rate, gas/bloating, lack of energy and headaches. Those people also said Garcinia did not help them lose weight.
Some lab rat research suggests the HCA in Garcinia Cambogia might be toxic to the testis. Not all researchers agree with this. To be safe, men should discuss this with their urologist for more up to date information.
And then there is the liver failure controversy. Let's take a closer look at that next.
Garcinia Cambogia And Liver Failure
For several years, there have been reports of hepatitis, liver toxicity and liver failure resulting from Garcinia cambogia supplements. Most of these reports stem from the use of a Garcinia-containing supplement called Hydroxycut.
Since Hydroxycut contained many ingredients, this makes it difficult to know which ingredient was responsible. That said, there is at least on report of a 34-year-old male who needed a liver transplant. He admitted to taking two 80mg capsules of “Swanson Premium Brand Garcinia Cambogia 5:1 Extract.” This supplement ONLY contained garcinia Cambogia.
For those doing their own research, here are some of case reports and review articles I found:
- Hepatotoxicity associated with Garcinia cambogia: A case report
- Hepatotoxicity Associated with Use of the Weight Loss Supplement Garcinia cambogia: A Case Report and Review of the Literature.
- Acute Hepatitis due to Garcinia Cambogia Extract, an Herbal Weight Loss Supplement.
- Hydroxycut hepatotoxicity
- Hydroxycut(®) (herbal weight loss supplement) induced hepatotoxicity: a case report and review of literature
- Hepatotoxicity due to hydroxycut: a case series
- Hepatoxicity associated with weight-loss supplements: A case for better post-marketing surveillance
- Severe hepatotoxicity due to Hydroxycut: a case report
- Hydroxycut hepatotoxicity: A case series and review of liver toxicity from herbal weight loss supplements
- Fatal liver failure following food supplements during chronic treatment with montelukast.
- Two patients with acute liver injury associated with use of the herbal weight-loss supplement Hydroxycut
Many other supplements are linked to liver failure too.
See the Supplements & Liver Failure review for more information
Garcinia Cambogia And Rhabdomyolysis
Rhabdomyolysis is a serious medical condition that results in your muscles dying. Kidney failure is one of the most serious side effects of this disorder, which is abbreviated as “Rhabdo.”
Back in 2004, there was a case report of a 54-year-old woman who got rhabdo after taking a supplement that contained garcinia Cambogia as wel as well as many other ingredients- including ephedra. Stimulants have been known to cause rhabdomyolysis. Other than this report, I'm not aware of any cases of garcinia cambogia causing rhabdo.
Regardless, if you think you have rhabdo, my best advice is to go to your doctor – or hospital. A simple blood test can tell if you have it or not. Rhabdo is VERY serious condition that can result in kidney failure. Do not take this lightly.
How Much Works?
On the Dr. Oz segment on Garcinia cambogia, you may have heard that they recommended 1500-3000 mg (1.5 grams to 3 grams) per day, that contained at least 50% of hydroxycitric acid (HCA).
Notice from the review of the research above that as much as 3.45 grams of Garcinia have been used with positive results. I mention this for those in which 3 grams did not work.
- I see no proof that more than 3.45 grams of Garcinia cambogia is needed.
- Garcinia cambogia should be taken on an empty stomach, about 30 minutes before meals.
- Many Garcinia cambogia supplements also contain calcium or potassium. This is to increase the absorption.
It's likely that they will see Garcinia cambogia supplements that also contain other ingredients, like,
Or whatever else is the “hot, sexy” supplement of the month.
Dr. Oz And Garcinia Cambogia
It's likely that many people first heard of Garcinia cambogia extract when it was featured on the Dr. Oz show. While I do agree that Garcinia is one of the least expensive weight loss supplements, I was disappointed that there was no mention of the potential for liver toxicity. I did like it when Dr. Oz stated “You should never see my picture next to it (Garcinia cambogia). “If you see my picture next to it, that means they're stealing from you.”
Dr. Oz knows that as soon as he mentions a supplement, people will try to use his picture and fame to promote their product. Dr. Oz does not sell any supplements and he does not endorse any particular brand of Garcinia supplement.
Does Garcinia Cambogia Work?
Despite the hype, I'm not convinced. I see just as many studies showing it works as doesn't work. But, more troubling is the potential for liver failure.