Raspberry ketone is a natural compound responsible for the distinct aroma of red raspberries. Found in small quantities in various fruits, it has gained attention in the supplement industry for its purported weight management benefits.
What is Raspberry Ketone and Where Does It Come From?
Raspberry ketone, or 4-(4-hydroxyphenyl)butan-2-one, is a phenolic compound that gives red raspberries their characteristic scent and flavor. It also occurs naturally in other fruits like cranberries and blackberries, and in the bark of trees such as yew, maple, and pine. Natural sources contain very low concentrations, typically 1-4 milligrams per kilogram. Extracting it directly from fruit for commercial use, especially in supplements, would be extremely expensive, costing up to $20,000 per kilogram. Consequently, most commercial supplements use synthetically produced raspberry ketone, often through chemical reactions like the condensation of 4-hydroxybenzaldehyde with acetone followed by catalytic hydrogenation.
Why Are People Interested in Raspberry Ketone?
The primary driver behind raspberry ketone’s popularity is its association with weight loss. Proponents claim it aids fat reduction through several proposed mechanisms. One theory suggests it may increase adiponectin, a hormone that regulates glucose and fatty acid breakdown, leading to improved fat metabolism.
Another claim is that raspberry ketone stimulates lipolysis, the breakdown of fat cells, promoting the release of fatty acids for energy. Some cell-based studies indicate it might boost fat-breakdown enzymes like hormone-sensitive lipase (HSL). It is also hypothesized to increase metabolism by influencing norepinephrine levels. Beyond weight loss, raspberry ketone is used as a flavoring agent in foods and beverages, and as a fragrance in cosmetics and perfumes.
What Does the Science Say About Raspberry Ketone?
Despite the claims, robust human clinical trials supporting raspberry ketone for weight loss are largely absent. Existing research is predominantly limited to animal studies (mice and rats) or in-vitro (test-tube) studies. While some animal studies show it might reduce weight gain or increase fat breakdown, these findings do not reliably translate to human efficacy or safety.
The doses used in animal studies are often significantly higher than those in human supplements, sometimes reaching hundreds of milligrams per kilogram of body weight. For instance, some mouse studies used doses of 330 mg/kg or 500 mg/kg, with higher doses leading to mortality. Human supplement dosages range from 100 to 1400 mg per day, which, compared to its low natural occurrence, raises safety concerns.
Concerns regarding potential side effects and safety have been raised, especially given high supplement doses and limited human data. Investigations using quantitative structure-activity relationship (QSAR) models indicate potential cardiotoxic effects and possible impacts on reproduction and development. A case of coronary vasospasm was associated with raspberry ketone intake. The lack of stringent regulation for dietary supplements means consumers may be exposed to high, untested doses. The current scientific consensus indicates insufficient evidence to support raspberry ketone’s effectiveness for weight loss or other health benefits in humans.