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Bitter orange (Citrus aurantium)

Synonyms/Common Names/Related Substances:

  • Aurantii pericarpium, auraptene, bergamot aromatherapy oil, bergamot orange, bergapten, beta-daucosterol(XI), beta-sitosterol, bigaradier, bitter orange extract, bitter orange peel, chisil, Citri aurantii fructus (CAF), Citri grandis pericarpium (CGP), Citrus amara, Citrus aurantium, Citrus aurantiumdulcis, Citrus aurantium extract (CAE), Citrus aurantium L., Citrus aurantium L. var. amara, Citrus aurantiumsinensis (CAS), Citrus aurantium ssp. bergamia, Citrus aurantium var. amara, Citrus aurantium var. dulcis (sweet orange), Citrus bigarradia, citrus essential oils (EOs), citrus extract, Citrus L. Rutaceae, citrus peel extract, Citrus silension (CS), Citrus unshiu Marcovitch, Citrus vulgaris, Citrus xaurantium, corteza de naranja (Spanish), Cyathofora Y.Tanaka, Daidai, flavanones, furocoumarins, fructus Aurantii, Goutou orange, Goutou sour orange, green orange, hesperidin, hordenine, Kijitsu, limonene, marmalade, marmin, meta-synephrine, m-synephrine, naranja amarga (Spanish), naringin, neohesperidin, neroli oil, N-methyltyramine, nobiretin, nonvolatile fraction, octopamine, oil of bergamot, oxedrine, oxypeucedanin, oxy-psoralen (5-[(6',7'-dihydroxy-3',7'-dimethyl-2-octenyl)], para-octopamine, para-synephrine, pericarps of Citrus grandis, phenethylamine alkaloids, phenylephrine, pomeranze, Poncirus trifoliata x C. aurantium sour orange, p-synephrine, Rutaceae (family), satsuma mandarins, Seville, Seville orange, shangzhou zhiqiao, sour orange, sour orange flower, sour orange juice, sour orange leaf, sweet orange, synephrine, synephrine alkaloids, synephrine HCl, synthetic synephrine, tangeretin, tyramine, volatile oil, xiangcheng, xiucheng, zhiqino, zhi qiao, zhi shi.
  • Combination product examples: Advantra Z® (Nutratech, Inc.); dannang recipe no. 2 (aucklandia root, red peony root, giant knotweed rhizome, scutellaria root, honeysuckle flower, forsythia fruit, rhubarb, immature bitter orange, magnolia bark, peach kernel, red sage root, licorice root, boiled with water); Lean System 7™; Metabolift Ephedra-Free Formula® (Twinlab Corporation); Nutrex™ Lipo-6x; Rauvolfia-Citrus tea (foliage of Rauwolfia vomitoria and bitter orange fruit); Stacker 2 Ephedra-Free (NVE Pharmaceuticals); Xenadrine EFX® (Cytodyne Technologies); Zhizhu® (rhizoma Atractylodis macrocephalae and fructus Aurantii immaturus; either Citrus aurantium L. (IFCA) or Citrus sinensis Osbeck (IFCS)).

Clinical Bottom Line/Effectiveness

Brief Background:

  • Bitter orange (Citrus aurantium) is a flowering, fruit-bearing evergreen tree native to tropical Asia that is now widely cultivated in the Mediterranean region and elsewhere.
  • Bitter orange is commonly used in dietary supplements as an aid for fat loss and as an appetite suppressant.
  • Bitter orange contains synephrine, an alkaloid with similarities to ephedrine. The U.S. Food and Drug Administration (FDA) banned the sale of ephedrine-containing dietary supplements. Some products previously containing ephedrine have been reformulated to include Citrus aurantium.
  • It is claimed that bitter orange is an effective aid to weight loss and a safe alternative to ephedra. Although various adverse effects have been attributed to bitter orange or p-synephrine, there is little concrete evidence to suggest the lack of safety of these products. According to an extensive review published by the Natural Health Products Directorate of Health Canada (NHPD), Health Canada has approved the use of up to 50mg daily of p-synephrine or p-octopamine alone in healthy adults, or up to 40mg of p-synephrine p-octopamine in combination with up to 320mg of caffeine daily. According to secondary sources, a separate scientific literature review conducted by Intertek Cantox suggested that p-synephrine is "unlikely to have significant effects on inotropy, vasoconstriction, or blood pressure." The authors also suggested that single doses of up to 70mg of p-synephrine alone or divided doses of up to 100mg of p-synephrine alone daily, or single doses of 40mg of p-synephrine in combination with 320mg of caffeine or divided doses of 70mg of p-synephrine in combination with 400mg of caffeine are unlikely to cause adverse effects.

Dosing/Toxicology

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Precautions/Contraindications

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Interactions

Most herbs and supplements have not been thoroughly tested for interactions with other herbs, supplements, drugs, or foods. The interactions listed below are based on reports in scientific publications, laboratory experiments, or traditional use. You should always read product labels. If you have a medical condition, or are taking other drugs, herbs, or supplements, you should speak with a qualified healthcare provider before starting a new therapy.

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Mechanism of Action

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History

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Evidence Table

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Evidence Discussion

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Products Studied

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Author Information

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References

Natural Standard developed the above evidence-based information based on a thorough systematic review of the available scientific articles. For comprehensive information about alternative and complementary therapies on the professional level, go to www.naturalstandard.com. Selected references are listed below.

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The information in this monograph is intended for informational purposes only, and is meant to help users better understand health concerns. Information is based on review of scientific research data, historical practice patterns, and clinical experience. This information should not be interpreted as specific medical advice. Users should consult with a qualified healthcare provider for specific questions regarding therapies, diagnosis and/or health conditions, prior to making therapeutic decisions.