Garcinia Cambogia for Weight Loss: Evidence and Safety

Hydroxycitric acid inhibits ATP-citrate lyase, the enzyme that supplies acetyl-CoA for fatty acid synthesis. That is a coherent mechanism in a test tube. Whether it meaningfully changes body composition in humans eating a normal diet is a different question, and the trial data suggests not very much.

• Body weight: a meta-analysis of randomised trials found a mean difference of -0.88 kg against placebo, a result the authors themselves described as small.
• Appetite: proposed via serotonin pathways, inconsistently demonstrated.
• Duration: no trial has shown whether any effect persists beyond 12 weeks.

This entry is here because the ingredient is common in the catalogue. On the evidence, it is not one we would put forward.

Onakpoya 2011 systematic review and meta-analysis of hydroxycitric acid for weight loss found a small significant difference and noted that trials were small and short. The NIH LiverTox monograph documents the association with clinically apparent acute liver injury, and a 2022 review examined whether hydroxycitric acid is the trigger. Case reports of severe injury continue to accumulate.

Products typically supply 500-1,500 mg of extract standardised to 50-60% HCA, taken before meals. Given the size of the effect and the liver signal, there is no dose at which the trade looks good, and anyone taking it should keep the duration short and stop at any sign of liver trouble.

Headache, nausea, GI symptoms and dizziness are the common ones. The serious concern is idiosyncratic hepatotoxicity: case reports document acute liver injury, some severe, some requiring transplantation. Proposed mechanisms include an immune-mediated reaction associated with the HLA-B*35:01 allele. Stop immediately and seek medical advice for jaundice, dark urine, pale stools or right-sided abdominal pain.

May add to the effect of glucose-lowering medication. Serotonergic activity raises a theoretical concern alongside SSRIs and other serotonergic drugs. Avoid alongside any medication with its own hepatic burden. It should not be combined with other weight-loss products carrying liver signals.