Chlorogenic acid is a natural compound found in a wide array of plants. It is a polyphenol that is an important intermediary compound in plant metabolism, and also has a broad range of antimicrobial properties. This phytochemical is found in high concentrations in coffee. It is an antioxidant and has been shown to be a tumor inhibitor. This chemical has also been found to inhibit the release of glucose into the blood, and appears to help people lose weight.

Many of the polyphenols function as antioxidants. Chlorogenic acid is able to neutralize several classes of carcinogenic compounds before they can damage DNA, thus preventing mutations from occurring and causing cancer. It also inhibits oxidation of the low-density lipoprotein (LDL), or bad cholesterol. Such oxidation can damage the arteries and cause atherosclerosis. Limiting this is thought to help prevent cardiovascular disease.

A number of population studies identified coffee drinkers, who drank at least five cups a day, as being substantially less likely to get Type 2 diabetes. Further research has suggested the reason for this as being the effects of chlorogenic acid on glucose metabolism. Glucose is stored in the liver in a polysaccharide called glycogen, which is a long, branched chain of insoluble glucose molecules. In a process known as glycogenolysis, the enzyme glucose-6-phosphatase releases free glucose into the bloodstream, where it circulates to various organs.

If glycogenolysis is inhibited, the body gets its energy from fat cells. This reduces blood glucose levels, helping to reduce the symptoms of diabetes. Also, reducing the number of fat stores should help in losing weight.

There is good evidence that chlorogenic acid inhibits glucose-6-phosphatase. It has been shown with both animal and human liver extracts to inhibit the enzyme. Sometimes compounds work in lab studies with cellular extracts, but are not absorbed by the body. This polyphenol was detected in the blood of coffee drinkers after they drank the beverage, however, so it clearly is absorbed into the system.

The biological effects of chlorogenic acid have led to its being marketed for weight reduction in Europe. The substance is obtained from green coffee and sold as Svetol®, which is typically included as an ingredient in mints, chewing gum, and coffee. While one must always be cautious when using weight loss supplements, there is some data — from the manufacturer — to suggest that this product does result in weight loss. This is accomplished because inhibiting glucose-6-phosphatase reduces the amount of glucose in the blood after meals. For safety, a doctor should be consulted before taking any supplement.