A1 Keto BHB is a product backed by extensive research. But what makes the extract so successful? The active ingredient found within the fruit’s rind is called hydroxycitric acid (HCA). HCA is a potent extract that can accelerate weight loss in one of three ways. The first benefit is the ability for HCA to burn fat. There’s an enzyme in your body known as citrate lyase that turns certain foods into fat. HCA targets this enzyme and prevents it from storing excess fat.