Common Names: bitter orange, Seville orange, sour orange, zhi shi
Latin Names: Citrus aurantium
- Native to eastern Africa, the Arabian Peninsula, Syria, and Southeast Asia, bitter orange now is grown throughout the Mediterranean region and elsewhere, including California and Florida.
- Bitter orange has been used in traditional Chinese medicine for indigestion, nausea, and constipation.
- Today, people use various bitter orange products as a dietary supplement for heartburn, nasal congestion, weight loss, appetite stimulation or suppression, and athletic performance. Bitter orange is also applied to the skin for pain, bruises, infections, and bed sores. Bitter orange has been used in cooking and for adding flavor to beer and spirits.
- The fruit of bitter orange contains the component p-synephrine and other naturally occurring chemicals. p-Synephrine is structurally similar to ephedrine, the main chemical in the herb ephedra, but p-synephrine has different pharmacologic properties (how the chemical acts). Ephedra is banned from dietary supplements by the U.S. Food and Drug Administration because it raises blood pressure and is linked to heart attack and stroke. Bitter orange is commonly used as a substitute for ephedra in dietary supplements.
- The National Collegiate Athletic Association (NCAA) has placed “synephrine (bitter orange)” on its current list of banned drugs, listing it as a stimulant.
- The fruit, peel, flower, and oil are used and can be taken by mouth in tablets and capsules. Bitter orange oil can be applied to the skin.
How Much Do We Know?
- A small number of studies have investigated the usefulness of bitter orange for health purposes in people.
What Have We Learned?
- Applying bitter orange oil to the skin may help with ringworm, jock itch, and athlete’s foot infections.
- There’s not enough scientific evidence to show whether bitter orange is helpful for other health purposes, such as weight loss.
What Do We Know About Safety?
- Bitter orange is likely safe when used orally in amounts commonly found in foods.
- There is one case report of a woman having a faster-than-normal heart rate at rest after taking a dietary supplement that contained only bitter orange. There are other case reports of healthy people experiencing fainting, angina, heart attack, and stroke after taking bitter orange as part of multicomponent products. However, because these products contained multiple ingredients, it is difficult to know the role that bitter orange played.
- Evidence regarding the effects of bitter orange (alone or combined with other substances, such as caffeine and green tea) on the heart and cardiovascular system are inconclusive. Some studies showed that bitter orange raised blood pressure and heart rate, but other studies showed that bitter orange didn’t have this effect at commonly used doses.
- Some sources list bitter orange as a stimulant whereas other sources say that it’s not a stimulant at commonly used doses.
- Because bitter orange products have not been proven safe and because the effects of using them during pregnancy and breastfeeding are unknown, pregnant women and nursing mothers should avoid these products.
Keep in Mind
- Take charge of your health—talk with your health care providers about any complementary health approaches you use. Together, you can make shared, well-informed decisions.
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ODS seeks to strengthen knowledge and understanding of dietary supplements by evaluating scientific information, supporting research, sharing research results, and educating the public. Its resources include publications (such as Dietary Supplements: What You Need to Know), fact sheets on a variety of specific supplement ingredients and products (such as vitamin D and multivitamin/mineral supplements), and the PubMed Dietary Supplement Subset.
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- Bitter orange. Natural Medicines website. Accessed at naturalmedicines.therapeuticresearch.com/ on October 11, 2018. [Database subscription].
- Bouchard NC, Howland MA, Greller HA, et al. Ischemic stroke associated with use of an ephedra-free dietary supplement containing synephrine. Mayo Clinic Proceedings. 2005;80(4):541-545.
- Firenzuoli F, Gori L, Galapai C. Adverse reaction to an adrenergic herbal extract (Citrus aurantium). Phytomedicine. 2005;12(3):247-248.
- Gange CA, Madias C, Felix-Getzik EM, et al. Variant angina associated with bitter orange in a dietary supplement. Mayo Clinic Proceedings. 2006;81(4):545-548.
- Nykamp DL, Fackih MN, Compton AL. Possible association of acute lateral-wall myocardial infarction and bitter orange supplement. Annals of Pharmacotherapy. 2004;38(5):812-816.
- Orange peel, bitter. In: Blumenthal M, Goldberg A, Brinckmann J, eds. Herbal Medicine: Expanded Commission E Monographs. Newton, MA: Integrative Medicine Communications; 2000:287-289.
- Office of Dietary Supplements website. Dietary Supplements for Weight Loss. Accessed at https://ods.od.nih.gov/factsheets/WeightLoss-HealthProfessional/ on October 10, 2019.
- Rasmussen CB, Glisson JK, Minor DS. Dietary supplements and hypertension: potential benefits and precautions. Journal of Clinical Hypertension. 2012;14(7):467-471.
- Shara M, Stohs SJ, Smadi MM. Safety evaluation of p-synephrine following 15 days of oral administration to healthy subjects: a clinical study. Phytotherapy Research. 2018;32(1);125-131.
- Smith TB, Staub BA, Natarajan GM, et al. Acute myocardial infarction associated with dietary supplements containing 1,3 dimethylamine and Citrus aurantium. Texas Heart Institute Journal. 2014;41(1):70-72.
- Stohs SJ, Badmaev V. A review of natural stimulant and non-stimulant thermogenic agents. Phytotherapy Research. 2016;30(5):732-740.
- Thomas JE, Munir JA, McIntyre PZ, et al. STEMI in a 24-year-old man after use of a synephrine-containing dietary supplement: a case report and review of the literature. Texas Heart Institute Journal. 2009;36(6):586-590.
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