Bitter orange (Citrus aurantium)


Bitter orange (Citrus aurantium) comes from a flowering evergreen tree of tropical Asia. Bitter orange trees are now widely grown in the Mediterranean region and elsewhere.
Bitter orange contains synephrine, a compound similar 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 bitter orange
Bitter orange is commonly used in dietary supplements for fat loss and as an appetite suppressant. It is claimed that bitter orange is an effective aid to weight loss and a safe alternative to ephedra. Various adverse effects have been contributed to bitter orange or p-synephrine. However, there is little concrete evidence to suggest the lack of safety of these products.

Related Terms

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))

evidence table

These uses have been tested in humans or animals. Safety and effectiveness have not always been proven. Some of these conditions are potentially serious, and should be evaluated by a qualified healthcare provider.
Adjunct in surgery (Grade: C)
Use of bitter orange before surgery improved anxiety. A combination product with bitter orange improved symptoms associated with gallbladder removal. However, the effect of bitter orange alone is unclear. Further research is needed.
Aging (Grade: C)
Limited research indicates that a combination product with bitter orange may improve symptoms of aging. However, more, high-quality studies are needed.
Dementia (behavior challenges) (Grade: C)
Bitter orange has been used in aromatherapy. Bitter orange does not seem to reduce combative, resistive behaviors in people with dementia. Further studies are needed on this topic.
Diabetes (Grade: C)
Limited research reports that bitter orange may reduce blood sugar after meals and during fasting. Further studies on the effect of bitter orange alone are needed.
Exercise capacity (Grade: C)
A combination of synephrine (a component of bitter orange) and caffeine may make exercise feel easier and increase blood pressure and blood sugar. Further research on bitter orange is needed.
Fungal infections (Grade: C)
Preliminary research shows promising results using bitter orange oil as an antifungal agent. However, further evidence is needed to confirm these results.
Indigestion (Grade: C)
Early research suggests that bitter orange pills may benefit people with indigestion. Further research is needed before a conclusion may be made.
Mood enhancement (Grade: C)
A component of bitter orange, p-synephrine, lacked effect on mood and energy. Further research is needed before a conclusion may be made.
Weight loss (Grade: C)
Research suggests that weight loss may be enhanced by a bitter orange product. Additional high-quality studies on bitter orange alone are needed.