The new guidance updates Health Canada’s "Guidelines for the Use of Synephrine” from 2010, which limited daily intake of p-synephrine to 30 mg, and prohibited products containing both p-synephrine and caffeine without extensive human clinical studies.
The new guidelines now classifies up to 50 mg of p-synephrine per day for healthy adults as a Type III health risk, relating to “a situation in which the use of, or exposure to, a product is not likely to cause any adverse health consequences”.
The same Type III classification applies to products containing a combination of up to 40 mg of p-synephrine in combination with a maximum of 320 mg of caffeine per day.
Products reportedly containing bitter orange or p-synephrine are typically positioned in the weight loss segment, and reports also suggest efficacy in the relief of heartburn, and loss of appetite, as well as skin infections such as ringworm and athlete's foot.
The ingredient’s profile has increased since ephedra was banned by the US Food and Drug Administration (FDA) in 2004 as it contains similar compounds and has been favored by dietary supplements manufacturers as an ephedra substitute. It is most often consumed in pill-form but can also be applied to the skin.
There have been some questions raised over the safety of bitter orange-containing supplements.
However, Dr Sidney Stohs from Creighton University recently reviewed 22 reports submitted to the Center for Food Safety and Applied Nutrition (CFSAN) of the US Food and Drug Administration (FDA) in the Journal of Functional Foods (doi: 10.1016/j.jff.2010.10.003), and concluded that, given the “poly-herbal, poly-alkaloidal composition of the products involved” it was “unwarranted and unjustified” to say that bitter orange and p-synephrine were responsible for adverse events.
This was supported by a toxicology study from scientists at the US Food and Drug Administration (FDA) published in Birth Defects Research Part B: Developmental and Reproductive Toxicology (doi: 10.1002/bdrb.20308).
Health Canada’s report was welcomed by Bob Green, president of Nutratech, Inc., manufacturer of the bitter orange extract product Advantra Z, as “very good news for makers of weight management, sports nutrition, and energy supplements.
“Not only because Health Canada’s report validates the safety of p-synephrine, but also because this government agency has looked past the hype and evaluated the scientific data behind this tried-and-true thermogenic ingredient,” he added.
Health Canada added that cautionary label statements will be required on products containing more than 50 mg p-synephrine, and noted that this dosage should be avoided by children, women who are pregnant and nursing, and people who take blood pressure and/or thyroid medications, sympathomimetics, or monoamine oxidase inhibitiors (MAOIs).
Health Canada’s report is currently available upon request, but will soon reportedly be available via the American Botanical Council website.