Are Natural Weight Loss Products Safe? Part 3: Bitter Orange

By Ginger Hultin, MS, RDN, LDN

The active component in Nature’s Way Bitter Orange product has been studied with interest for its role in weight loss, and despite much caution with regards to side effects, has proven relatively safe in some animal and human research. ­­­­The product has shown some efficacy for modest weight loss and has made its way onto the Generally Recognized as Safe (GRAS) list when consumed as a food (peel, flower or leaf). However, when taking the extract which acts like a stimulant to the sympathetic nervous system, or the body’s fight-or-flight system, there are some warnings and it has been labeled “Possibly Unsafe” by Natural Medicine’s Database. Understanding Bitter Orange requires looking at the research that has been done regarding dose, length of use and which medical conditions are contraindicated. ­­­­

The active component of Bitter Orange or Citrus aurantium for weight loss is called synephrine. The amount of synephrine that could be stimulating will come in the form of a concentrated extract that is much more potent than what you could eat through food sources alone. The Nature’s Way bottle contains 6% synephrine from Bitter Orange extract and carries a warning regarding anyone with heart disease, high blood pressure or taking an MAOI (a type of medication). There is 900mg of synephrine in two tablets of this product. Bitter orange contains adrenergic (aka ‘stimulating’), agents synephrine and octopamine and has the potential to increase blood pressure or prove toxic to the heart in some people. Despite the possible dangers, reviews of human clinical studies of synephrine have shown few side effects, especially when taken alone instead of combined with other herbs or stimulants. Studies included observed the use of 132-528mg of synephrine per day for a length ranging from 6-12 weeks. Significant adverse events were not seen in a review of 20 studies including 360 participants. Though studies remain mixed on the safety of synephrine from Bitter Orange, there is a call in the research world for larger, more rigorous clinical trials to better understand the safety and efficacy. As always, communicate with your health care provider and use caution when taking a supplement such as this.

Synephrine stimulates the sympathetic nervous system which can cause blood pressure to rise as the muscles in blood vessels constrict or tighten. It can also stimulate the heart. Synephrine is similar to the compound phenylephrine (also called “neo-synephrine) that exists in some nasal decongestants. In some ways, it also mimics the compound ephedrine contained in the banned herb ephedra. Synephrine has been shown to raise body temperature similarly to ephedrine, but does not have the same stimulating effect on heart rate or blood pressure. The effects of both are compounded by mixing with caffeine. Ephedrine has been shown to cause a stronger reaction and it is not suggested that any person take this compound since it has been banned by the FDA since 2004. Use caution when taking synephrine or Bitter Orange supplements with any other product that could decrease blood sugar, increase blood pressure or is a stimulant, such as caffeine.  There are some moderate to major drug interactions so please meet with your doctor to discuss interactions with medications, before a lab draw or if you have any medical conditions.  Finally, know that bitter orange or synephrine is banned by the National Collegiate Athletic Association (NCAA) as a performance enhancer.

Possible Side Effects/Interactions:

Because the category of weight loss supplements has a tainted past, it is important to use caution when using a product like this. Most importantly of all, mention use of Bitter Orange or synephrine to your doctor or pharmacist for safety with any medical condition or drug interaction. While it may be appropriate for some people and assist in weight loss when combined with healthy eating and exercise, use caution with Bitter Orange if you have any type of heart problem, blood pressure issues or take medications such as MAOI. A doctor can help guide you on the length of time you should take a product like this one and if it is appropriate for you.

Read Part 1 Are Natural Weight Loss Supplements Safe?

Read Part 2 New Products For Weight Loss: Garden of Life Raw

Read Part 4, Do Natural Weight Loss Product Work?: NOW Foods Super Citrimax®

Read Part 5, Weight Loss Products: White Kidney Bean Carb Intercept

Read Part 6:  Garcinia Plus Meratrim® Gold

References (if needed):

Fugh-Berman AMyers A. Citrus aurantium, an ingredient of dietary supplements marketed for weight loss: current status of clinical and basic research. Exp Biol Med. 2004 Sep;229(8):698-704.

Stohn SJ, Preuss HG, Shara M.  A review of the human clinical studies involving Citrus aurantium (bitter orange) extract and its primary protoalkaloid p-synephrine. Int J Med Sci. 2012;9(7):527-38.

Ginger Hultin, MS, RDN, LDN, is a Chicago-based nutrition writer and dietitian at the Block Center for Integrative Cancer Care specializing in integrative health and whole food-based nutrition. Ginger earned her Bachelor of Arts in English from the University of Washington and her Master of Science in Nutrition from naturopathic Bastyr University. She serves as President for the Chicago Academy of Nutrition and Dietetics. Ginger is a plant-based dietitian who has a passion for physical activity and cooking. She believes that an interest in unprocessed foods and natural health will help heal the chronic health problems our country has been facing. Follow Ginger on her blog: ChampagneNutrition (, Twitter (@GingerHultinRD), Instagram (, and Pinterest ( 


About Ginger Hultin

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