What is Garcinia Cambogia?
Garcinia cambogia (Garcinia gummi-gutta), also known as Malabar tamarind, is native to Southeast Asia. It is small, pumpkin-shaped, and is reddish-yellow in color. The fruit skin is usually used as a food preservative, flavoring agent, and traditionally in many Asian regions for the treatment of constipation, piles, rheumatism, edema, irregular menstruation and intestinal parasites.  
The fruit pulp and rind contain a high concentration of (-)-hydroxycitric acid (HCA), one of the main compounds responsible for the beneficial effects reported in several studies on body weight regulation. 
Where is Garcinia Cambogia Found?
G. cambogia supplements come in varying dosages—on Amazon.com alone, checking ten separate brands, the variety was 500-1500 mg—and usually have an HCA concentration between 60 and 95 percent. Some are pure G. cambogia, but many are a mixture of different ingredients rather than G. cambogia alone. The most common companions are potassium and a mixture of potassium-calcium-chromium. 
3 Interesting Facts About Garcinia Cambogia
- G. cambogia may be used to reach a feeling of satiety (fullness).
- G. cambogia can have a diuretic property (increases urination).
- G. cambogia can be used for the cure of some bowel disorders.
Health Benefits of Garcinia Cambogia
Although many studies have been focused on the anti-obesity activity of G. cambogia/HCA supplements, other studies have evaluated its anti-inflammatory, anti-diabetic, anti-oxidant, anti-microbial, anti-ulcer and hepato(liver)-protective properties.
Several studies reported the anti-obesity activity of G. cambogia supplements, though none specified the concentration of HCA in those supplements.
A daily intake of 300 mg HCA for 14 days was found to reduce body weight and 24-hour energy intake (appetite, food intake) in humans. 
Dr. Kiwon Lim of Konkuk University in Seoul, Korea, and other researchers reported an increase in fat metabolism and improved exercise performance in women who took HCA, 250 mg/day orally for 5 days. 
Another study on obese individuals reported a good body weight regulation after the consumption of two different doses of G. cambogia-derived HCA (2800 mg/day and 5600 mg/day). 
Appetite Suppression and Satiety (Feeling Full)
After an intake of supplement containing G. cambogia extract combined with Ascophyllum nodosum (a seaweed) extract and l-carnitine during 1 week, 28 people showed an increase in feeling full with reduction of hunger pangs. 
An intake of 500 mg/day HCA supplement, showed a positive effect on the glucose absorption rate and post-meal glucose spikes in a seven-day human study. 
Anti-Inflammatory Activity, Plus Anti-Ulcer Activity and Gastric Healing
An extract from G. cambogia rind analyzed at a concentration of 25 mg/mL reported an antimicrobial activity against E. coli, staph infection, and some other bacterial infections. 
“The fruit contains xanthones, which inhibit pre-neoplastic lesions in [breast] and colon cancer. The xanthones may also induce apoptosis [cell death] in mouth, leukemia, breast, gastric, and lung cancer cell lines in vitro.”  [definition added]
It has been reported that a water extract of G. cambogia fruit rind prevents the breakdown of communication between nerves, a common symptom of Alzheimer’s. Like a safety in football ensures the smooth passage of the ball downfield, protecting passes from interception, G. cambogia performs the same function in the brain, blocking enzymes that interfere with synapse communication.
Is Garcinia Cambogia Ever Bad for You?
There are many opinions on the safety of G. cambogia on the scientific community. Even though some cases of toxicity have been reported, the majority of studies agree on the general non-toxicity of G. cambogia. The recommended dose for safe use is up to 2800 mg/day based on the “no observed adverse effect level.”  
But the safety of G. cambogia supplements for weight control has been called into question in various news reports.
A case report was done in regard to suspected serotonin toxicity for a 35-year old woman who consumed a G. cambogia-containing supplement daily for 2–3 months. She presented with stuttering speech and profuse sweating. The supplement contained these active ingredients: 1000 mg G. cambogia extract (60 percent HCA), plus a combination of potassium-calcium-chromium ingested at a dose of 2 capsules 3 times per day. It turned out the woman had also been taking an anti-depressant (SSRI), and both substances interacted to produce a toxic level of serotonin (a neuro-transmitter in the brain that regulates mood). She hadn’t told her doctor she was also taking the weight-loss supplement. With treatment she made a full recovery. One of the case report authors was hesitant to label G. cambogia dangerous just from the one incident, as it was never determined clearly that the G. cambogia and not one of the other ingredients was to blame, but suggested extra care should be observed with patients taking SSRIs. 
In 2009, the US Food and Drug Administration (FDA) identified the consumption of the HCA-containing supplement Hydroxycut, manufactured by Iovate/MuscleTech, as a possible cause of liver damage. The original Hydroxycut formula had already been changed in 2004 when the FDA first banned ephedrine because of toxicity reports; the second formula replaced the ephedrine with Gymnema sylvestre, retaining the rest of the ingredients: Green Tea Extract, Konjac (a fiber source), Guarana , and G. cambogia extracts. The 2009 warning changed the formula again after reports of liver damage and other health problems (rare cases, but enough for the FDA to issue a warning). Today, Hydroxycut has replaced all previous ingredients, no longer containing G. cambogia.  
But several studies have indicated that HCA itself, and thus G. cambogia, may not be the culprit. Dr. Sidney J. Stohs, Pharmacy PhD from the University of Nebraska, and colleagues reported that while some cases of toxicity and specifically liver damage have been associated to the consumption of Hydroxycut products, it was premature to blame HCA for that damage; mainly because some of the Hydroxycut products tested did not contain HCA, but did contain up to 20 other ingredients. So while HCA might be involved, there was no conclusive evidence of such. 
Other studies, by Dr. Stohs and others, suggest that a moderate dosage of G. cambogia (HCA) by itself, barring other pre-existing health problems, is safe: the maximum daily safe dosage was determined as 2800 mg/day. Of course, research is ongoing.   
While there are still some differing opinions on the effectiveness and safety of G. cambogia and HCA, especially in combination products, the news seems promising. Of course, no one supplement is ever going to be a “miracle pill;” healthy eating and regular exercise will always be a part of maintaining fitness. But it does seem this little fruit may have a lot to offer.