Also known as: Garcinia gummi-gutta, HCA, Hydroxycitric acid, Malabar tamarind, Brindleberry
Fat MetabolismEmerging evidence
A tropical fruit rind standardised for hydroxycitric acid, and one of the most heavily marketed weight loss ingredients ever sold. The trial evidence is weak and the safety picture is less clean than most botanicals here.
Typical dose
500.0–1500.0 mg per day
30-60 minutes before meals
What it is
Garcinia gummi-gutta is a small pumpkin-shaped fruit native to Southeast Asia and India, where the rind has long been used in cooking, particularly in curries, as a souring agent.
The compound of interest is hydroxycitric acid, or HCA, found in the rind. Extracts are standardised to HCA content, commonly 50 to 60 per cent.
Its culinary history is genuine, but the doses used in supplements are far above anything achieved by using the rind as a souring ingredient. That distinction matters when traditional use is offered as reassurance, because the two exposures are not comparable.
How it works
HCA inhibits ATP citrate lyase, an enzyme involved in converting carbohydrate into fatty acids. The reasoning is that blocking it reduces the conversion of excess carbohydrate to fat.
The problem with that logic is that converting carbohydrate to fat is not a major pathway in humans eating ordinary diets. Excess carbohydrate is mostly stored as glycogen or simply burned in preference to fat, so inhibiting a minor pathway achieves little.
A second proposed mechanism involves serotonin and appetite, which is the basis for the appetite suppression claims. This is also the more likely explanation for some of the reported side effects.
What the evidence shows
Meta-analyses of garcinia for weight loss have generally reported differences of around one kilogram or less against placebo over several weeks, with authors repeatedly noting that the magnitude is of questionable clinical relevance and that trial quality is poor.
A well-conducted larger trial found no significant difference in fat loss between garcinia and placebo, which is the finding that best matches the mechanistic objection above.
The honest summary is that garcinia is among the most heavily marketed and least well supported ingredients in this index. Its market presence reflects marketing spend rather than evidence, and anyone buying it for fat loss should know that before spending.
Dosing
Typical products supply 500-1,500 mg of extract two or three times daily, taken 30-60 minutes before meals. Trials have used HCA doses across a wide range without establishing a clear dose-response.
Dose against HCA content rather than extract weight.
The more useful guidance is about expectations. The evidence does not support meaningful fat loss, and no dose changes that. If you are choosing where to spend on a fat loss goal, this is not the place, and the money is better put toward things with actual support behind them.
At a glance
Common forms
50-60% HCA extract, Calcium/potassium HCA salts, Capsules and tablets, Within weight management blends
Half-life / duration
HCA clears within hours
Timing
30-60 minutes before meals
Competition status
Permitted — not on the WADA Prohibited List
Category
Fat Metabolism
Safety and side effects
Common reported effects are mild: digestive upset, headache and nausea.
The safety picture is less clean than for most botanicals in this index. Reports of liver-related adverse effects associated with garcinia-containing products have accumulated over the years, and several regulators have issued warnings on that basis. Many cases involved multi-ingredient products where attribution is uncertain, but the signal is persistent enough to state plainly rather than omit.
Because of the proposed serotonin mechanism, take care if you take anything that acts on mood. Stop and seek advice if you notice yellowing of the skin or eyes, unusually dark urine, abdominal pain or unexplained fatigue.
Who should avoid it
Avoid if you have been told your liver is not working normally, or if you take medication that places a load on it. Stop and seek medical advice if you notice yellowing of the skin or eyes, dark urine, abdominal pain or unexplained fatigue. Speak to your doctor before use if you take regular medication, particularly anything acting on mood, or if your blood sugar is being managed. Avoid in pregnancy and breastfeeding.
This entry is provided for information only. Food supplements should not be used as a substitute for a varied and balanced diet and a healthy lifestyle. Consult a qualified healthcare professional before use if you are pregnant, breastfeeding, taking medication or under medical supervision.
