NOTE: After knee surgery last week I've been subjected to a lot of television watching, fertile grounds for scams and claims that demand skeptical dissection. There will be a few reports along this line over the coming weeks.
Lipozene. The commercials claim rapid weight loss. They appear highly clinical and are quite persuasive. Lipozene is packaged and pitched with an implicit claim of miracle weight loss drug status. The product and the clinical claims come from the Obesity Research Institute. The Obesity Research Institute LLC is a Los Angeles based company founded in 2003 that has sold several ill-fated products such as fiber-thin and Propylene. A quick search of the scholarly literature shows no formal published research results from the Obesity Research Institute, so this appears to be a company and not a place actively engaged in scientific research.
I was particularly drawn into the commercial when I read the blue italic print under the Lipozene name. It says, Amorphophallus konjac, which just happens to be one of my favorite plants. So Lipozene is just a derivative of A. konjac, actually the ground up corum (bulb). The bulb has high levels of glucomannan, a carbohydrate that swells massively when wet. It is used as a gelling agent in some Asian cuisine. This explains the role of this compound in Lipozene.
As a diet compound glucomannans have been shown to be mildly effective in weight loss. The most compelling data come from 1984 and the International Journal of Obesity (8(4):289-93) where Walsh and colleagues gave 1 g of glucomannan or a placebo in a double blinds study. Over eight weeks the glucomannan group lost significantly more weight (5.5 lbs over 8 weeks).
The red flag for me is that this paper is from 1984 and there is no evidence of a successful replication or expansion of the study. This was a dead end. In the field of weight loss, we'd expect more labs to pile on to these findings and do their own trials. In reality, they probably did, and didn't see the same results. Independent replication is the Achilles Heel of flawed or just plain wrong studies.
Other studies, mostly by Dr. Dan Gallaher's lab at the University of Minnesota, do show a positive effect of glucomannan in lowering blood lipid profiles, increasing their presence in the feces. Serum cholesterol decreases. His work spans many similar compounds and I absolutely trust these data.
But these are the best tests. Recent evidence tests glucomannan and outside of small, uncontrolled studies there is little treatment effect in weight loss. It does appear to promote relief from constipation, lowers blood lipid profiles and probably can be regarded as safe. The mild effects in weight loss probably stem from the swelling of the compound in the gut, leading to an increased feeling of satiety in those that use it.
The problem for me comes from the fact that this is a ground up plant bulb and it can be purchased for a much lower price than from Lipozene. Google "glucomannan" and you'll find hundreds of vendors. Also, check for complaints against Lipozene and the Obesity Research Institute. I won't go into detail here, but a quick check shows a history of lawsuits and unauthorized charges, at least as evidenced by the web results.
So the Obesity Research Institute straddles the scientific fence with this claim. With a foot in reality and the other in hyperbole, they stretch the science to sell a familiar plant compound as a magic bullet for weight loss. Testimonies abound on the web, for and against the product. The science tells a different story. Clearly some positive effects, but not a consistent record of promoting weight loss over placebo in well-constructed studies.