Does Garcinia Cambogia Work? (A Meticulous Review)
It’s darn near impossible to know what to believe about any weight-loss supplement, right?
Garcinia Cambogia extract is no different. If you watch TV or read Internet articles, you’ll hear hundreds of different stories about whether it’s a miracle drug or a complete scam. And you just don’t know whom to trust.
I feel the exact same way. Clearly, if there is an effective, all-natural weight-loss pill that’s 100% safe, then I want to use it.
But because I don’t know who to trust about Garcinia Cambogia, I decided to comb through all of the clinical trials and peer-reviewed journal articles.
If you want to jump to the answer I got after all my research, just jump down to the section titled “Does Garcinia Cambogia Work?” If you want a more in-depth understanding, then please keep reading.
What is Garcinia Cambogia?
Quick Answer: Garcinia Cambogia is a smallish fruit found in many South Asian countries that has traditionally been used in curries and for its medicinal properties (most notably aiding digestion).
As you can see from the image above, Garcinia Cambogia (sometimes also known as Malabar tamarind, Assam fruit, or Garcinia gummi-gutta) is a squat, pumpkin-like fruit about the size of an orange. It’s often green or light yellow on the outside with a rather sour tasting fruit inside. The fruit is fairly fleshy and falls apart into segments (like an orange or more like a durian) and also has dark pods in them that can be removed fairly easily.
Garcinia Cambogia can be found in many South Asian countries as well as parts of Africa, and it’s used in many curries.
Indian Ayurvedic medicine also promotes the fruit as aiding digestion (due to its sourness). Additionally, the fruit rind, leaves, and roots, have traditionally been used for various medicinal purposes from healing rickets and bone fractures to treating rheumatism and tumors.
What Health Benefits Does Garcinia Cambogia Supposedly Have?
Quick Answer: Garcinia Cambogia is supposed to aid weight loss in 3 ways: (a) suppressing appetite, (b) preventing excess carbohydrates in your body from being converted to fat, and (c) preventing emotional eating by increasing serotonin production.
What’s special about Garcinia Cambogia is that its rind contains high concentrations of a chemical called hydroxycitric acid (often shortened to HCA). Many people claim that HCA has various benefits for weight loss and for general health.
The potential weight loss benefits of Garcinia Cambogia have been rumored for quite a while, but the popularity of this supplement has grown substantially over the past few years.
Interest surged especially after Dr. Oz recommended it. For instance, one article on his website claims (with a link to a journal article) that “[w]ith proper weight-loss efforts (dieting and exercising), the average person taking HCA lost an average of four pounds a month.”
In general, there are 3 main claims that people and websites promoting the use of Garcinia Cambogia (or rather the HCA found in Garcinia Cambogia) point to:
- it burns fat;
- it suppresses appetite; and
- it improves your mood.
Even Amazon reviews of Garcinia Cambogia extract supplements echo these same claims: “Works great, curbs appetite, improves my mood, decreases inches in tummy fast.”
All of these health claims make Garcinia Cambogia extract sound fantastic, but you should know by now that what I’m really interested in is the hard science…
Incidentally, garcinia cambogia seems to be so popular, it’s even sold at the checkout area in Whole Foods:
Does Garcinia Cambogia Work?
Quick Answer:Probably Not. And if it does work, it doesn’t do much.
Sadly, the science currently doesn’t really support the claims made about Garcinia Cambogia.
So what does the science say?
First of all, remember that journal article cited on Dr. Oz’s website? I went and read that 2005 article, and that article is authored partly by people who work at the company that manufactures a form of HCA that the article is claiming to be superior to other HCA compounds for weight loss. (You can find the full article here). The article goes through many of the studies done on HCA and draws the conclusion that their specific HCA compound (the one they sell and own the patent on) is effective at obesity management. Well, more on whether their special compound might work or not later.
Let’s Start with the Rat Studies of Garcinia Cambogia
Garcinia Cambogia studies on rats are a little mixed, but some do show that it promotes weight loss.
1. 2001 Physiology and Behavior Journal article by Leonhardt M et al. In this study, the researchers studied 24 rats, trying to determine whether Garcinia Cambogia helped prevent the rats from regaining weight they’d previously lost on a calorie restrictive diet. Conclusion: “HCA reduced body weight regain after substantial body weight loss.”
2. 1981 American Journal of Physiology article by Greenwood MR et al. In this study, the researchers studied the effect of HCA on the body composition of both obese and lean rats. Conclusion: “[T]he obese rat, despite a substantial reduction in body weight produced by [HCA], still defends its obese body composition.” In other words, HCA had a short-term effect, but no long-term effect.
3. 1977 American Journal of Clinical Nutrition article by Sullivan C et al.. In this study, the researchers examined the effect of HCA on 3 types of obese rats. Conclusion: in all 3 types, “food intake and body weight gain were reduced significantly by the chronic oral administration of a nontoxic dose of [HCA].”
So far, the rat studies look pretty promising. At the very least, there appears to be a short term effect, and at best, weight loss may be a long-term result.
Sadly, as Kris Gunnars points out, “what works in rats doesn’t always work in humans.”
The Human Studies of Garcinia Cambogia Are Not as Promising
Here are a few of the human studies that I found most interesting and pertinent (in order of rigorousness):
1. 1998 Journal of the American Medical Association article by Heymsfield SB et al.. This group of researchers studied 135 people (which is the largest randomized control study I’ve found on this issue) over a period of 12 weeks while prescribing them a high fiber, low calorie diet. Conclusion: “Garcinia Cambogia failed to produce significant weight loss and fat mass loss beyond that observed with placebo.” This study was graded 5 on the Jadad scale by the Peninsula Medical School reviewers from this paper, which means that it’s considered a very rigorous clinical trial (the Jadad scale ranges from 0 being the least rigorous to 5 being the most rigorous).
The largest and most rigorous clinical study on humans found no weight loss benefit to Garcinia Cambogia supplementation.
2. 2004 Diabetes, Obesity and Metabolism Journal article by Preuss HG et al.. These researchers examined the effect of a salt of HCA (HCA with calcium and potassium) often referred to as Super CitriMax, which has been patented. The study was a randomized, double-blind, placebo-controlled human study conducted on 60 moderately obese people over an 8 week period. Conclusion: At the end of the 8 weeks, body weight and BMI decreased by 5-6% in both groups that were given the HCA salt. This study was rated a 4 on the Jadad scale by the Peninsula Medical School reviewers. In 2005, they repeated the study with 90 people and found similar results.
I know I sound a bit skeptical here, but I do want to point out that the co-authors of the 2004 and 2005 studies immediately above were from the company that holds the patent on Super CitriMax. Seems like a possible conflict of interest to me.
3. 2001 International Journal of Obesity article by Kovacs EM et al.. In this study, the researchers studied 11 men (small sample size) with a 2-week supplementation of HCA or HCA plus MCT (medium-chain triglycerides like those found in coconut oil). The men got to choose their own meals but were provided with the same-calorie snacks during each day. Conclusion: HCA supplementation didn’t result in any more weight loss than the placebo for the men that lost weight.
They did a similar study with 7 males and 14 females and again found that many people in the study lost weight, but those with HCA supplementation didn’t lose more than those without any supplementation.
Both of the Kovacs studies were rated a 3 on the Jadad scale by the Peninsula Medical School reviewers.
What Can We Learn from the Human Studies of Garcinia Cambogia?
Garcinia Cambogi may produce a very small short-term benefit for weight loss and no long-term benefits.
This 2011 review published in the Journal of Obesity indicates that there have been quite a few animal and human trials on Garcinia Cambogia (they identified 5002 potential references at the beginning of their research). However, once they excluded all studies that didn’t meet certain basic criteria (e.g., on humans, investigating weight-loss, randomized, double-blind, & placebo-controlled), only 11 clinical studies were good enough to include in the review, and even these 11 studies all “had one or more methodological weaknesses.” Interestingly, 7 of those studies did not specify their sources of funding (maybe I’m being overly suspicious here).
Still, after reviewing those 11 more-rigorous studies, the researchers found that Garcinia Cambogia showed no statistically significant long-term effects on weight loss. They found that there were some short-term effects, but those effects were very minor.
Their conclusion was as follows:
“The evidence from [the studies] suggests that Garcinia extracts/HCA generate weight loss on the short term. However, the magnitude of this effect is small, is no longer statistically significant when only rigorous [studies] are considered, and its clinical relevance seems questionable.”
You can also find a list of various studies that have concluded Garcinia Cambogia extracts to result in no weight loss (table 4) and in weight loss (table 3) in this review study.
Is Garcinia Cambogia Safe?
Garcinia Cambogia is generally considered safe (even if it’s not effective for weight loss).
It has been eaten as a fruit and used as a flavoring agent and medicine for a long time in various cultures.
And a review study of Garcinia Cambogia articles found that “to date, there is no case study or report showing the direct adverse effect of HCA,” although it offered an upper safety level of 2800 mg/day and acknowledged that there have been a few adverse reports on weight-loss diet supplements including Garcinia Cambogia or HCA as an active ingredient.
However, clinical trials have some reported some potential minor adverse effects of Garcinia Cambogia, including headache, skin rash, common cold, and gastrointestinal symptoms. And Dr Oz’s article suggests caution if you’re breast-feeding, pregnant, taking diabetic medication or statins, or if you have dementia or Alzheimer’s.
Garcinia Cambogia extracts have caused gastrointestinal issues for some people.
Is Garcinia Cambogia a Scam?
No – there’s no real scam here.
There are definitely some studies that suggest a small aid to weight loss and there don’t appear to be any serious side effects.
However, there’s very little evidence that Garcinia Cambogia is effective in humans at promoting weight loss, curbing appetite, or improving mood.
I definitely felt a bit annoyed after spending an entire day reading scientific studies, because I just couldn’t find anything to support all the amazing claims that seem to be made on hundreds of websites.
Should You Try Garcinia Cambogia?
I’m not going to try it, but I also can’t answer this question for you.
I’ve given you all the information I found and reviewed, and I hope it helps you make a more informed decision.
From my perspective, I think we’re still better off focusing on eating real food, sleeping enough, and reducing stress. For weight loss and for health, I haven’t yet found anything (in my life or in the scientific literature) that works better.
If you want to read more, please check out Kris Gunnars’ article on Garcinia Cambogia. I didn’t read it until I’d written this article – mostly because I wanted to reach my own conclusions from the scientific literature rather than reading other people’s conclusions. But now that I’ve read it, his is an excellent article.
And please, let me know what you think in the comments below. Does Garcinia Cambogia work for you or have you had success with some other supplements?
Images: Copyright (c) sriharun from Fotolia and joanna wnuk from Fotolia