Parts Used & Where Grown
The dried outer peel of the fruit of bitter orange, with the white pulp layer removed, is used medicinally. The leaves are also commonly used in many folk traditions. The bitter orange tree is indigenous to eastern Africa, Arabia, and Syria, and cultivated in Spain, Italy, and North America.
Our proprietary “Star-Rating” system was developed to help you easily understand the amount of scientific support behind each supplement in relation to a specific health condition. While there is no way to predict whether a vitamin, mineral, or herb will successfully treat or prevent associated health conditions, our unique ratings tell you how well these supplements are understood by the medical community, and whether studies have found them to be effective for other people.
For over a decade, our team has combed through thousands of research articles published in reputable journals. To help you make educated decisions, and to better understand controversial or confusing supplements, our medical experts have digested the science into these three easy-to-follow ratings. We hope this provides you with a helpful resource to make informed decisions towards your health and well-being.
3 Stars Reliable and relatively consistent scientific data showing a substantial health benefit.
2 Stars Contradictory, insufficient, or preliminary studies suggesting a health benefit or minimal health benefit.
1 Star For an herb, supported by traditional use but minimal or no scientific evidence. For a supplement, little scientific support.
This supplement has been used in connection with the following health conditions:
Indigestion, Heartburn, and Low Stomach Acidity
3 cups of tea daily, prepared with 1 to 2 grams of dried peel
Bitter orange has traditionally been used as a digestive aid.
Bitter herbs are thought to stimulate digestive function by increasing saliva production and promoting both stomach acid and digestive enzyme production. As a result, they are particularly used when there is low stomach acid but not in heartburn (where too much stomach acid could initially exacerbate the situation). These herbs literally taste bitter. Some examples of bitter herbs include greater celandine, wormwood, gentian,dandelion, blessed thistle, yarrow, devil’s claw, bitter orange, bitter melon, juniper, andrographis, prickly ash, and centaury.. Bitters are generally taken either by mixing 1–3 ml tincture into water and sipping slowly 10–30 minutes before eating, or by making tea, which is also sipped slowly before eating.
Very little published research is available on the traditional uses of as a digestive aid and sedative. The German Commission E has approved the use of bitter orange for loss of appetite and dyspeptic ailments. One test tube study showed bitter orange to potently inhibit rotavirus (a cause of diarrhea in infants and young children). Bitter orange, in an herbal combination formula, reportedly normalized stool function and completely eased intestinal pain in 24 people with non-specific colitis and, again in an herbal combination formula, normalized stool function in another 32 people with constipation.
Refer to label instructions
Bitter orange has a history of use as a calming agent and to counteract insomnia.
has a history of use as a calming agent and to counteract insomnia. There is no clinical trial data to support its efficacy in this regard. The usual amount of tincture used is 2 to 3 ml at bedtime.
An amount providing not more than 70 mg of synephrine alone, or not more than 40 mg of synephrine in combination with up to 320 mg of caffeine
Bitter orange contains synephrine, which might promote weight loss.
Citrus and citrus extracts have long been used to promote weight loss, and research suggests, in general, they have small positive effects on body weight and waist circumference. Bitter orange (Citrus aurantium) and its active constituent, synephrine, are sometimes included in weight-loss formulas. Synephrine has been found to activate a type of nerve receptor that helps regulate carbohydrate and fat metabolism. Studies in healthy adults have noted single doses of bitter orange extract increased fat-burning during exercise in men and women, and energy used during digestion, a major avenue for expending calories, in women, but not men. Synephrine is a weak stimulant, and is often combined with stronger central nervous system stimulants, particularly caffeine, which may increase calorie-burning. Two clinical trials examining the effect of combination supplements containing bitter orange extract have noted positive effects on weight loss. However, in a randomized controlled trial using bitter orange alone in subjects with overweight and obesity, no weight loss was attributable to the supplement after six weeks.
Reports on the possible blood pressure-raising effect of single doses of bitter orange extract in healthy individuals have been mixed. An industry-sponsored review of 20 published and unpublished studies with a combined total of approximately 360 subjects concluded taking bitter orange or synephrine, alone or in combination with other ingredients (one of which was usually caffeine), for six to twelve weeks has been associated with slight weight loss and has had no substantial adverse effects on heart rate or blood pressure.
Traditional Use (May Not Be Supported by Scientific Studies)
Bitter orange is used similarly in a wide variety of traditions. In Mexico and South America the leaf is used as a tonic, as a laxative, as a sedative for insomnia, and to calm frazzled nerves.1, 2 The peel of the fruit is used for stomach aches and high blood pressure.3, 4 The Basque people in Europe use the leaves for stomach aches, insomnia, and palpitations and the bitter orange peel as an anti-spasmodic.5 In traditional Chinese medicine, the peel of the immature fruit is used for indigestion, abdominal pain, constipation, and dysenteric diarrhea. Where the patient is weak, the milder, mature fruit is used similarly.6 Bitter orange continues to be widely used for insomnia and indigestion in many parts of the world.7
How It Works
How It Works
Bitter orange has a complex chemical makeup, though it is perhaps most known for the volatile oil in the peel. The familiar oily residue that appears after peeling citrus fruit, including bitter orange, is this volatile oil. It gives bitter orange its strong odor and flavor, and accounts for many of its medicinal effects. Besides the volatile oil, the peel contains flavones, the alkaloids synephrine, octopamine, and N-methyltyramine, and carotenoids.8, 9
How to Use It
Usually 1 to 2 grams of dried peel is simmered for 10 to 15 minutes in a cup of water; three cups are drunk daily. As a tincture, 2 to 3 ml (with a weight-to-volume ratio ranging from 1:1 to 1:5) is often recommended for use three times per day. 10 The purified volatile oil is generally avoided for reasons discussed in the side effects section.
Interactions with Supplements, Foods, & Other Compounds
Decoctions of bitter orange substantially increased blood levels of cyclosporine in pigs, causing toxicity.11 Bitter orange also inhibited human cytochrome P450 3A (CYP3A) in the test tube.12 This is an enzyme that helps the liver get rid of numerous toxins, and strongly affects metabolism of certain drugs. Bitter orange might, therefore, interact with drugs that are metabolized by CYP3A. To be on the safe side, bitter orange should not be combined with prescription medications, unless someone is under the care of an experienced natural medicine clinician.
Interactions with Medicines
Bitter orange oil may possibly cause light sensitivity (photosensitivity), especially in fair-skinned individuals.13 Generally this occurs only if the oil is applied directly to the skin and then exposed to bright light; in rare cases it has also been known to occur in people who have taken bitter orange internally. The oil should not be applied topically and anyone who uses it internally should avoid bright light, including tanning booths.
Internal use of the volatile oil of bitter orange is also potentially unsafe and should not be undertaken without expert guidance. Large amounts of orange peel have caused intestinal colic, convulsions, and death in children.14 The amounts recommended above for internal use should not be exceeded.
One text on Chinese medicine cautions against the use of bitter orange in pregnancy.15 This concern is not raised in any other reference, and the American Herbal Products Association classifies the herb as "class 1," an herb that can be safely consumed during pregnancy when used appropriately.16
1. Martinez M. Las Plantas Medicinales de Mexico. Mexico City: Libreria y Ediciones Botas, 1991.
2. Gonzalez-Ferrara MM. Plantas medicinales del noreste de Mexico. Monterey, Mexico: Grupo Vitro, 1998.
3. Gonzalez-Ferrara MM. Plantas medicinales del noreste de Mexico. Monterey, Mexico: Grupo Vitro, 1998.
4. Bejar E, Bussmann R, Roa C, Sharon D. Herbs of Southern Ecuador: A Field Guide to the Medicinal Plants of Vilcabamba. Spring Valley, CA: LH Press, 2001.
5. Molina GV: Plantas Medicinales en el Pais Vasco. San Sebastian, Spain: Editorial Txertoa, 1999.
6. Bensky D, Gamble A, Kaptchuk T. Chinese Herbal Medicine: Materia Medica, rev. ed. Seattle: Eastland Press, Inc., 1993.
7. Hernandez L, Munoz RA, Miro G, et al. Use of medicinal plants by ambulatory patients in Puerto Rico. Am J Hosp Pharm 1984;41:2060-4.
8. Blumenthal M, Goldberg A, Brinckmann J, eds. Herbal Medicine: Expanded Commission E Monographs. Newton, MA: Integrative Medicine Communications, 1999.
9. Dr. Duke's Phytochemical and Ethnobotanical Databases. Cited 2003 Jul 11. Available from URL: www.ars-grin.gov, 2002.
10. Blumenthal M, Goldberg A, Brinckmann J, eds. Herbal Medicine: Expanded Commission E Monographs. Newton, MA: Integrative Medicine Communications, 1999.
11. Hou YC, Hsiu SL, Tsao CW, et al. Acute intoxication of cyclosporine caused by coadministration of decoctions of the fruits of Citrus aurantium and the pericarps of Citrus grandis. Planta Med 2000;66:653-5.
12. Guo LQ, Taniguchi M, Chen QY, et al. Inhibitory potential of herbal medicines on human cytochrome P450-mediated oxidation: Properties of umbelliferous or citrus crude drugs and their relative prescriptions. Jpn J Pharmacol 2001;85:399-408.
13. Blumenthal M, Goldberg A, Brinckmann J, eds. Herbal Medicine: Expanded Commission E Monographs. Newton, MA: Integrative Medicine Communications, 1999.
14. McGuffin M, Hobbs C, Upton R, Goldberg A, eds. American Herbal Products Association's Botanical Safety Handbook. Boca Raton, FL: CRC Press, 1998.
15. Bensky D, Gamble A, Kaptchuk T. Chinese Herbal Medicine: Materia Medica, rev ed. Seattle: Eastland Press, Inc., 1993.
16. McGuffin M, Hobbs C, Upton R, Goldberg A, eds. American Herbal Products Association's Botanical Safety Handbook. Boca Raton, FL: CRC Press, 1998.
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Last Review: 05-12-2015
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The information presented by TraceGains is for informational purposes only. It is based on scientific studies (human, animal, or in vitro), clinical experience, or traditional usage as cited in each article. The results reported may not necessarily occur in all individuals. For many of the conditions discussed, treatment with prescription or over the counter medication is also available. Consult your doctor, practitioner, and/or pharmacist for any health problem and before using any supplements or before making any changes in prescribed medications. Information expires December 2023.