Raspberry ketones are a natural compound found in plants chemically similar to capsaicin and synephrine, two substances that might regulate metabolism. Ketones in the raspberry plant give the fruit its pleasant scent and represent a common flavoring ingredient in processed food. Cosmetics companies also use the compound to give products an aromatic scent. Raspberry ketones were marketed as a weight-loss supplement after studies with rats showed possible fat-burning properties.
Capsaicin gives hot peppers their spicy flavor and might increase metabolism. Synephrine, an alkaloid found in bitter orange extract, represents a form of ephedrine, a stimulant commonly added to weight-loss supplements. Raspberry ketones have similar qualities without the burning effect of hot chili peppers.
In some cultures, the leaf and berry of the plant served as medicine for centuries, both as a topical application and health food. A tea made from raspberry leaves treated intestinal problems, such as diarrhea, heart problems, diabetes, and flu symptoms. Some traditional medicine practitioners recommended raspberry consumption to cleanse the body because they might induce perspiration and urine flow.
Raspberry ketones might also ease menstrual cramps and regulate heavy bleeding by relaxing muscle spasms. In pregnancy, the chemicals might prevent morning sickness and decrease the pain of labor. Although supplements containing raspberry ketones might be safe, medical experts advise women to check with a doctor before using these supplements during pregnancy.
These substances might increase the effects of the hormone estrogen. Women who suffer from hormonal conditions linked to estrogen production should seek medical advice before using raspberry dietary supplements. These disorders include endometriosis, breast or ovarian cancer, and uterine fibroids.
A Japanese study using rats fed a high-fat diet and raspberry ketones showed they prevented weight gain and fat accumulation in the liver and other tissues. The animals' level of triglycerides, a form of fat stored for energy, fell, leading researchers to conclude ketones might prevent and treat obesity by boosting metabolism and burning fat as energy. The results have not been replicated in human trials.
Most synthetic dietary supplements contain 100 milligrams of ketones per tablet, but no recommended dosage has been set. Preliminary studies show no toxic adverse effects of the chemical at five times the average dose, but potential reactions from higher levels are not known. Ketones might react differently for individuals suffering certain health conditions or for the elderly.
In cosmetic body products, manufacturers have marketed creams and lotions to treat cellulite and skin rashes. These companies have proposed that ketones in the products activate lipase, a human enzyme found in the pancreas that breaks down fat in food so it can be absorbed. As with internal uses, no scientific evidence proves ketones reduce the appearance of cellulite.