Raspberry ketones are natural compounds in red raspberries that give them their scent. Supplement makers market them to boost fat metabolism, claiming they increase adiponectin and help break down stored fat. These claims are based on lab and animal work; well-controlled human studies are sparse.
Capsules are the typical form, and many products include caffeine or green tea extract. Doses vary widely, and people usually take them with meals. Reliable human trials have not shown meaningful weight loss or fat burning.
Raspberry ketones can act as a mild stimulant