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What is bitter orange?

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 made 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 amount of stimulants in the product is sometimes very difficult—if not impossible—to determine. Service members 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.

For more answers to common questions we’ve received about dietary supplements, please visit our Operation Supplement Safety (OPSS) FAQs.

Is there a list of dietary supplements/substances banned by the military?

There is no banned dietary supplement list in the military, but you can learn how to make informed decisions about dietary supplement use.

Lately, HPRC has been receiving a lot of questions about the use of banned supplements in the military, but the fact is: There isn’t a list of banned dietary supplements currently available. It isn’t always easy to determine whether a dietary supplement product is safe or not, so the Department of Defense (DoD), together with HPRC, provides helpful resources on the Operation Supplement Safety (OPSS) website to help you choose supplements wisely. With regard to the military’s stance on supplements in general, please see the OPSS FAQ about a "banned list," which is pertinent to all service branches.

Some dietary supplements, including ones sold on military installations, contain potentially harmful and problematic ingredients. For some tips about how to avoid these, read the OPSS infosheet “Red Flags—What You Need to Know.” In addition, some other potentially dangerous ingredients include prescription drug ingredients and their analogs, drugs banned by FDA for safety reasons, controlled substances (such as anabolic steroids), and untested/unstudied new active drug ingredients, which may not be listed on the product label.

One way to ensure that a dietary supplement product is safe is to see if it is third-party verified. Third-party certification organizations have developed criteria for evaluating and authenticating the quality of a supplement—the ingredients, the dosage levels, the level of contaminants, the label claims, and whether the manufacturing facilities follow Good Manufacturing Practices (GMP).

The Natural Medicines Comprehensive Database (NMCD) is the gold standard for evidence-based information on dietary supplement products and ingredients and is an HPRC partner. (Subscription is free if you have a “.mil” email address; visit the OPSS FAQ for more information.) NMCD rates products on a scale of 1 to 10 based on safety and effectiveness. We encourage you to consider only using products rated 8 or above.

To avoid potential problems, talk with your healthcare provider or dietitian before using dietary supplements. Also, see FDA’s list of tainted bodybuilding products, which includes important public notifications.