Raspberry ketone is a substance found in raspberries, which is responsible for their distinct smell.
A synthetic version of raspberry ketones is sold as a weight loss supplement.
How it works: In isolated fat cells from rats, raspberry ketones increase breakdown of fat and increase levels of a hormone called adiponectin, believed to be related to weight loss
Effectiveness: There is not a single study on raspberry ketones in humans, but one rat study using massive doses showed that they reduced weight gain
Side effects: They may cause your burps to smell like raspberries.