Raspberry ketone is a natural phenolic compound that is the primary aroma compound of red raspberries. It is most commonly used in perfumes, cosmetics, and as a food additive, that was until the infamous Dr. Oz promoted it on his show and now miraculously it is the solution for weight loss. In fact raspberry ketones have been around for years and have even been on the FDAs generally recognized as safe (GRAS) list since 1965 and have actually been in some over the counter diet pills and sold as its own weight loss supplement for quite some time, but with little success.
The problem with raspberry ketone and why I find it surprising that a doctor would promote this product, is that there is no human research or studies that have been done for this product. It is actually going off results done on rats and mice, and the researched showed that, compared to controls, raspberry ketone decreased the amount of fat in the liver and visceral adipose (abdominal fat) tissues of mice. It also significantly increased norepinephrine-induced lipolysis (the decomposition of fat) in some rat fat cells. While this research is encouraging it still does not mean that it would produce the same results in humans and much like the Acai Berry he promoted earlier that was also found to be no more than an antioxidant much like the blueberry and of no use for weight loss, the raspberry ketone seems headed for the same distinction.
There could be some hope for it though it seems that if combined with other supplements that it could be a part of a diet pill that could offer some results, but by itself it has proven to be ineffective.