A study published in Nutrition and Dietary Supplements found that Advantra Z—a bitter orange extract (p-synephrine)—increased appetite control, as well as energy levels, without adverse effects. It is the first scientific study to focus on Advantra Z's ability to suppress appetite and reduce food intake.

The placebo-controlled, double-blind study had 40 overweight adults consume a chocolate-flavored chew 15 to 30 minutes before their two largest meals of the day for a period of 30 days. The chews contained either placebo or 100 mg of bitter orange extract standardized to 51.5 mg p-synephrine (Advantra Z).  Each day, subjects completed a 13-item questionnaire rating eating control, energy level, and palatability.  

Subjects consuming chews containing Advantra Z reported significantly higher positive scores for eating/appetite control and energy enhancement as compared to placebo. All 40 subjects completed the study.  No adverse effects were reported in either the Advantra Z or placebo groups. The researchers noted that these results are consistent with previous studies associated with Advantra Z. 

Advantra Z, Novel Ingredient Service's proprietary bitter orange extract, is a patented thermogenic ingredient for diet, fitness, and energy. Introduced in 1996, Advantra Z's safety and efficacy is supported by more than 30 research studies. Laboratory analyses confirm that Advantra Z contains only natural p-synephrine, a stable synephrine isomer, and is devoid of m‑synephrine, which can increase blood pressure and heart rate in humans.