Chlorogenic acid is a phytochemical that is found in high amounts in raw coffee beans and is associated with antioxidant and anti-inflammatory properties. Roasting coffee beans significantly reduces the amount of chlorogenic acid.
It is an ester of caffeic acid and quinic acid. A total of 30% of ingested chlorogenic acid is absorbed by the small intestine and enters the blood circulation. The rest goes to colon where it may exert some biological effect. Some percentage of chlorogenic acid can be also absorbed in the colon. (1, 2)
There are claims that chlorogenic acid has weight loss properties. The evidence isn’t strong however and most of these claims are made by green coffee bean extract companies.