Raspberry ketones are phenolic compounds (a class of natural substances found in plants) derived from red raspberries. Raspberry ketones are responsible for the distinct aroma of raspberries, and are commonly used as a fragrance and/or food flavoring. When taken as a dietary supplement, raspberry ketones, Dr. Oz suggests, has been shown to increase fat loss through a number of different pathways. What are Raspberry Ketones? Raspberry has been used throughout the centuries for nutritional and medicinal purposes. Like its popular relatives, the strawberry and blueberry, raspberry contains an abundance of health promoting substances. The unique fragrance and flavor of raspberry comes from raspberry ketone (also known as 4-(4-hydroxyphenyl) but an 2-one), which is unique to a raspberry, and is widely used as a fragrance in cosmetics and as a flavoring agent in foodstuffs.