Bitter orange, also known as Citrus aurantium, is a citrus fruit originally used in Traditional Chinese medicine for stomach ailments, such as constipation, diarrhea, and indigestion.[1] Today, bitter orange extract, standardized to p-synephrine content, commonly occurs in multi-ingredient formulations labeled as ephedra-free supplements for weight loss: p-synephrine is an alkaloid compound structurally similar to adrenaline and the banned dietary supplement ephedrine.[2] The pharmacologic and pharmacokinetic properties of p-synephrine vary from its structural analogues enough to mitigate the risks previously seen with ephedrine-containing supplements. [1]. p-synephrine should also not be confused with m-synephrine, a synthetic amine derivative of synephrine. m-synephrine does not meet the FDA dietary supplement definition and is a prohibited ingredient.
What is bitter orange?
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•Last Updated: May 16, 2025
Bitter orange, or Citrus aurantium, is a citrus fruit used in Traditional Chinese Medicine for digestive issues and is also commonly found in weight loss supplements as p-synephrine, an alkaloid similar to adrenaline. Unlike ephedrine, p-synephrine has different pharmacologic properties that reduce the associated risks, and it should not be confused with the prohibited synthetic derivative m-synephrine.