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February 27, 2021

Findings about the Effect of Bitter Orange on Weight Loss

Anti-obesity effect of Bitter Orange (C. aurantium) contains synephrine which is a stimulant with similar properties as caffeine and ephedrine. It claims to have similar effects by increasing energy expenditure, increasing metabolism, and suppressing appetite and it has been labeled as the ephedra replacement. (1) Ephedra (ma-huang) is a Chinese shrub that has been known for at least 5,000 years. (2)

Ephedra- and ephedrine containing products may be modestly effective in promoting weight loss. However, the use of ephedra or ephedrine does cause an increase in jitteriness, mood changes, palpitations, nausea, and vomiting. The ephedrine alkaloids are stimulants that can increase heart rate and blood pressure. (3)

Banning of ephedra has paved the way for bitter orange to become a very widely used stimulant in fat burners.

In a clinical review of various studies done on bitter orange, the researchers reviewed numerous available clinical weight loss trials, physiological studies, and case reports of bitter orange.

Some promising evidence showed effect of   synephrine on treatment of obesity, but more rigorous studies are needed to draw adequate conclusions.

Another bitter orange study conducted by the department of physiology, medicine and pathology at the George town university found that bitter orange aided in weight loss and increase thermogenesis. (1)

A study was conducted to determine the effects of Bitter Orange extract, caffeine, and St. John's Wort (Hypericum perforatum) on body composition, metabolic variables, plasma lipid levels, and mood states in overweight healthy adults.

23 subjects were assigned to 1 of 3 groups: Group A received bitter orange extract 975 mg, caffeine 528 mg, and St. John's Wort 900 mg daily; group B received a maltodextrin placebo; and group C received nothing and served as the control group.

For 6 weeks, subjects were instructed by a registered dietitian on how to follow an 1800-kcal/d American Heart Association Step One diet and performed a 3-day/week circuit training exercise program under the supervision of an exercise physiologist.

Compared with subjects in the placebo and control groups, subjects in the treatment group lost a significant amount of body weight (1.4 kg). They also lost a significant amount of body fat (an average change of 2.9%). In terms of actual fat loss, group A lost a significant amount (3.l kg). No significant changes were noted in the results of the Profile of Mood States questionnaire for fatigue or vigor in any of the 3 groups. Group A experienced a decrease of both plasma cholesterol and triglycerides. No significant changes in blood pressure, heart rate or urinalysis findings were noted in any of the groups. Based on these results, it was concluded that the combination of C aurantium extract, caffeine, and St. John's Wort (Hypericum perforatum) is safe and effective when combined with mild caloric restriction and exercise for promoting both body weight and fat loss in healthy overweight adults. (4)




Bitter Orange synephrine has an anti-obesity effect. Bitter Orange is an appropriate alternative for Ephedra; Ephedrine present in Ephedra has side effects such as mood changes, nausea, and vomiting. Also the combination of Bitter Orange extract, caffeine, and St. John's Wort (Hypericum perforatum) is effective in  body weight loss and fat loss.


Key words: Bitter Orange, Promoting Weight Loss



1- A. Saonere Suryawanshi, J. (2011). An Overview of Citrus aurantium Used in Treatment of Various Diseases. African Journal of Plant Science, 5(7), 390-395. Retrieved from 


2- MR Lee, M.R. (2011). The history of Ephedra (ma-huang). The Journal of the Royal College of Physicians of Edinburgh, 41, 78–84. Retrieved from


3- Shekelle, P.G.,Hardy, M.L.,Morton, S.C.,Maglione, M.,Mojica, W.A.,Suttorp, M.J., …Gagné, J. (2003). Efficacy and Safety of Ephedra and Ephedrine for Weight Loss and Athletic Performance: A Meta-Analysis. The Journal of the American Medical Association, 289(12), 1537-45. Abstract retrieved from

4- M. Colker, C.,  S. Kalman, D.,  C. Torina, G.,  Perlis,  T.,  & Chris Street, Ch. (1999). Effects of Citrus aurantium Extract, Caffeine, and St. John's Wort on Body Fat Loss, Lipid Levels, and Mood States in Overweight Healthy Adults. Current Therapeutic Research, 60(3), 145-153. retrieved from


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