Hydroxycitric acid, or HCA is the active ingredient of Garcinia Cambogia's fruit rind. HCA may have the ability to boost fat-burning and suppress appetite, as it may block an enzyme called citrate lyase, which your body uses to make fat. It may also raise levels of the brain chemical serotonin, which affects mood and may make you feel less hungry. HCA and Garcinia Cambogia may offer support to those wishing to lose a few kilograms and it is more effective if taken in additional to a safe exercise plan and a well balanced diet.