According to the ingredient’s supplier Nutratech Inc., the study is the longest and highest-dose trial on bitter orange extract to date.
A new study finding weight-management ingredient Advantra Z bitter orange extract (Citrus arantium) without adverse effects when taken up to a twice daily at a dose of 49 mg will be published in Food and Chemistry Toxicology in May. According to the ingredient’s supplier Nutratech Inc. (West Caldwell, NJ), the study is the longest and highest-dose trial on bitter orange extract to date. (The study was available online in February.)
The study assessed the safety of 49 mg of bitter orange extract given to 75 healthy subjects twice daily for 60 days. Researchers observed no adverse cardiovascular, hepatic, renal, or hemopoietic effects. Additionally, they found no significant changes in systolic or diastolic blood pressure, blood chemistries, or blood cell counts in control or in the p-synephrine groups. (P-synephrine is the dominant amine in bitter orange extract.)
On the historical safety consensus for different p-synephrine doses, Nutratech says:
Guidelines from Health Canada support up to 50 mg of p-synephrine per day-or 40 mg of p-synephrine in combination with up to 320 mg of caffeine (October 2011). Intertek Cantox supported p-synephrine dosages up to 60 mg in 2012. However, after reexamining the scientific data in February 2013, the organization concluded that single p-synephrine dosages of up to 70 mg–100 mg-if taken as divided doses over the course of the day-are “not likely to cause adverse effects.” Prior to 2011, most authorities limited daily intake of p-synephrine to 20 and 30 mg.