Does Garcinia Cambogia Work for Weight Loss? What the Science Says

Does Garcinia cambogia work for weight loss? The short and simple answer to this question is no.

That’s not to say it has no physiological effect whatsoever. But if you’re expecting it to have a dramatic impact on the way you look, chances are you’re going to be disappointed with the results.

What is Garcinia Cambogia?

Garcinia cambogia is a small, pumpkin-shaped fruit that grows in India. It’s often used in Asian cuisine to make meals more filling. The rind of the fruit contains high levels of hydroxycitric acid, also known as HCA or Citrimax, which is the “active” ingredient found in many weight loss supplements.

Much of the interest in Garcinia cambogia was sparked by its appearance on the Dr Oz show, where it was touted as a “revolutionary fat buster” as well as an “exciting breakthrough” in natural weight loss.

The truth is that Garcinia cambogia is not new or revolutionary. Nor, as I’m about to explain, is it going to help you lose weight without diet or exercise.

How Does Garcinia Cambogia Work?

HCA, the active ingredient in the rind of Garcinia cambogia, is supposed to work by speeding up the rate at which stored fat is burned off, reducing the amount of carbohydrate that gets turned into fat, as well as helping you eat less by reducing your appetite.

However, the research results have been decidedly mixed, and many of the claims being made about HCA and weight loss don’t stand up to serious scrutiny.

Claim 1: Reduced Fat Storage

When you eat a meal containing carbohydrate, it eventually ends up in your bloodstream in the form of glucose. If that glucose isn’t used for energy right away, your body stores it in your muscles or liver in the form of glycogen.

If your glycogen stores are full, and you keep on eating a high-carbohydrate diet, your body needs somewhere to put it. And that’s where the problems start. When your muscles and liver are full, excess carbohydrate ends up being turned into fat, a process known as de novo lipogenesis, or DNL for short.

HCA is a competitive inhibitor of ATP-citrate lyase, an enzyme that plays a key role in lipogenesis, and has been shown to limit the conversion of carbohydrate to fat in subjects eating a high-carbohydrate high-calorie diet for seven days [1].

For the study, a group of 10 sedentary men performed a glycogen-depleting workout, followed by three days on a high-fat low-carbohydrate diet.

For the following week, the men were fed a high-carbohydrate diet containing 130-175% of their daily calorie requirements. During that time, they also took 500 milligrams of HCA three times a day or a placebo.

Although the effect was small, HCA did appear to limit the amount of carbohydrate that was turned into fat.

Here’s how the researchers sum up the results:

“We conclude that treatment with HCA seemed to result in a relatively lower (11%) net de novo lipogenesis. Although it remains questionable whether HCA may play a role as an agent in the treatment of obesity, we suggest that HCA may reduce net fat deposition from de novo lipogenesis during weight gain.”

However, this doesn’t mean much when it comes to weight loss.

First, while carbohydrate can be converted directly into fat, this doesn’t happen unless you’re eating a lot of it [2]. Remember, the subjects in this study were in a calorie surplus (meaning they were eating more than they needed to maintain their weight) rather than the calorie deficit required to lose fat.

DNL isn’t something that you need to worry about unless you’re eating a high-calorie diet containing large amounts of carbohydrate. That’s the exact opposite of what you should be doing if you’re trying to lose fat.

What’s more, DNL isn’t the only way that carbohydrate can contribute to fat being gained.

One of the main effects of overfeeding with carbohydrate is that it replaces fat as a source of energy. By suppressing fat burning, the fat in your diet is far more likely to end up being stored.

Garcinia cambogia extract might be able to slow the rate of DNL. But it won’t stop it completely. Eat too much carbohydrate, and, Garcinia cambogia or no Garcinia cambogia, you’ll end up gaining fat.

Claim 2: Faster Fat Burning

Not only is Garcinia cambogia supposed to inhibit the formation of fat, some say that it increases the amount of fat you burn.

It’s supposed to do this by reducing cell levels of malonyl-CoA, an enzyme that slows the rate at which fat is oxidized. This, in theory at least, would lead to an increase in the amount of fat you burn.

Putting the theory to the test, a team of scientists from Maastricht University put a group of ten cyclists through two trials, both of which involved two hours of cycling [3].

During the first trial, the cyclists consumed a drink containing 18 grams of HCA. In trial two, they were given plain water.

When they used HCA, the cyclists burned an average of 0.7 grams of fat per minute of exercise. Which is exactly the same amount of fat they burned after drinking plain water.

Despite the massive dose of HCA, it had no effect on the amount of fat burned during exercise. This is much in line with other research showing that HCA (3 grams daily) has no effect on fat oxidation at rest or during exercise [4].

Claim 3: Appetite Reduction

There are also claims that Garcinia cambogia increases glycogen storage in the liver, leading to a sensation of fullness and a reduced appetite. HCA has also been shown to affect brain levels of the chemical serotonin, which in turn can make you feel less hungry.

In one trial, HCA (300 milligrams three times daily) was shown to reduce 24-hour food intake in obese subjects by 15-30% with no increase in hunger [5].

Conversely, a three-month study of 89 overweight females at Purdue University shows that 1.2 grams of HCA daily had no effect on appetite [6].

A later study did find that high doses of HCA (2.8 grams per day) led to a faster rate of weight loss, mainly by suppressing the appetite and reducing calorie intake [7].

However, the fact that two of the study authors were involved with the company who make the supplement, but for some “mysterious reason” forgot to mention this in the research paper, does mean that we need to treat the results with some caution.

Does Garcinia cambogia Work for Weight Loss?

Does Garcinia cambogia work for weight loss? Probably not. Most of the higher quality research shows that it fails to produce significant weight loss beyond that seen with a placebo.

The largest and most rigorous study on HCA and weight loss was published in the Journal of the American Medical Association [8].

Subjects received either Garcinia cambogia extract (1500 milligrams of HCA per day) or a placebo for a total of 12 weeks. The average change in weight in both study groups is shown in the figure below

Although participants in both groups lost weight, there was no significant difference in weight loss between the two groups, which averaged 9 pounds in the placebo group and 7 pounds in the HCA group.

Researchers from the University of Exeter have also published something called a systematic review on the effectiveness of Garcinia cambogia extract as a weight loss supplement [9].

A systematic review is simply a way of summarizing research evidence. Systematic reviews are important because, rather than just cherry-picking research that supports your existing beliefs and ignoring everything else, you have a clear and transparent search strategy for finding data, you measure the quality of each study (ideally without knowing the results), and then present a balanced and impartial summary of the findings.

Here’s their conclusion:

“The evidence suggests that Garcinia cambogia extract/HCA generates weight loss on the short term. However, the magnitude of this effect is small, is no longer statistically significant when only rigorous randomized controlled trials are considered, and its clinical relevance seems questionable.”

Or to put it another way, when you strip out the low-quality studies, the research that’s left provides little in the way of compelling evidence to suggest that it’s worth spending your money on.

What Are the Side Effects of Garcinia?

Garcinia cambogia extract is relatively safe. Most research shows no significant difference in side effects when subjects are given HCA compared to those given a placebo [10]. However, a low risk doesn’t mean no risk at all. Just because HCA comes from a natural fruit doesn’t mean that it’s completely safe.

One of the big problems with dietary supplements in general is that they don’t always contain what they’re supposed to. Some will contain compounds (including drugs) that aren’t listed on the label [11].

In 2017, for example, the Food and Drug Administration issued a warning about a weight loss supplement called Fruta Planta Life. Although it was marketed as “Garcinia Cambogia Premium,” it actually contained a drug called sibutramine, an appetite suppressant that was removed from the market in 2010 due to concerns over safety.

Others might contain the right ingredients, but not in the declared potency or amount. In fact, laboratory tests show that many supplements contain substantially less HCA than the label claims.

In a 2018 study, one particular Garcinia cambogia supplement, labeled as containing 300 milligrams of HCA, actually contained just one tenth of that amount [12]. Of the five products that listed their HCA content, only two contained anything close to what was shown on the label.

In other words, there’s no guarantee that the actual amount of HCA in your supplements will match the HCA content on the label. While you can be relatively sure that a bottle of medication contains the ingredients it’s supposed to, the same can’t be said about dietary supplements.

Can Garcinia Cambogia Be Bad for Your Liver?

In May 2009, the Food and Drug Administration warned everyone to stop using a supplement containing HCA after receiving 23 reports of serious liver injuries, including one death.

The product in question (Hydroxycut) did contain other ingredients, so we can’t say for sure that Garcinia cambogia was to blame. However, there are a number of case reports that point towards a possible link between supplements containing HCA and liver damage.

In one report, a 57-year-old female with no previous history of liver disease ended up with acute hepatitis after taking Garcinia cambogia extract [13]. In fact, several cases of Garcinia cambogia associated liver failure have been reported in the literature [14, 15].

One guy needed a liver transplant after taking Garcinia cambogia extract three times a day for five months [16]. Liver damage due to other drugs and alcohol had been ruled out, and Garcinia cambogia was the only apparent risk factor.

Here’s how the researchers sum up their findings:

“While evidence from a case report rarely offers indisputable proof of causality, this case, in conjunction with known cases of hepatotoxicity and liver failure associated with other Garcinia cambogia-containing supplements warrants a high index of suspicion.”

To be clear, these are isolated case reports, and there’s no definitive proof of a cause and effect relationship between Garcinia cambogia supplements and liver damage. In general, no severe or serious adverse effects have been reported in studies that compare HCA with a placebo [17 ].

Given that HCA is largely worthless for weight loss, I have no idea why anyone would want to use the stuff. But if you do want to take it, and have pre-existing liver damage, or reason to believe that you might be genetically predisposed to liver problems, check with your doctor first.

Final Thoughts

There are so many supplements out there promising to help you lose weight. But if they’re really so good, why do supplement companies keep coming up with new ones?

Think about it. If raspberry ketones, green coffee bean extract, HCA or whatever else is on the Doctor Oz show this week actually worked as well as it’s supposed to, there would be no demand for another one.

There might be a small benefit in terms of appetite control with higher doses of HCA. But having looked through the research, as well as having tried it myself on several occasions, it’s not a supplement I would recommend using.