Bitter orange, synephrine, and octopamine are three ingredients I’ve seen a lot on Supplement Facts panels and labels. What are they?
Bitter orange is an extract from the immature green fruit of the Citrus aurantium plant, also known as Seville orange. It is sometimes used in small amounts in food as a flavorant and often used in weight-loss supplements. The terms “bitter orange,” “bitter orange extract,” or “Citrus aurantium” are often used interchangeably with the ingredient name “synephrine,” but bitter orange (the extract from Citrus aurantium fruit) is actually a complex mixture of many compounds, including synephrine and octopamine. Although both synephrine and octopamine occur naturally in the Citrus aurantium plant, they also can be synthesized in a laboratory.
Many safety concerns have been raised with regard to synephrine and octopamine, which are both stimulants. The National Collegiate Athletic Association (NCAA) bans both of them, but the World Anti-Doping Agency (WADA) bans only octopamine. Bitter orange is frequently used in "ephedra-free" products since 2004, when the Food and Drug Administration (FDA) banned ephedra for its association with serious adverse cardiovascular effects. Combinations of stimulants—such as bitter orange and caffeine, commonly found together in weight-loss and bodybuilding products—can cause hypertension and increase heart rate in otherwise healthy adults. A major concern with products that list bitter orange (or synephrine, or octopamine) on the label is that the concentration (or amount) of stimulants in the product is very difficult—if not impossible—to determine. Warfighters should exercise extreme caution when considering whether to use supplements containing bitter orange.
No conclusive, peer-reviewed, scientific evidence clearly establishes that bitter orange is any safer than ephedra. For more information on bitter orange and ephedra, read the monographs in HPRC’s Dietary Supplement Classification System series.
FAQ update 28 October 2014