Increased eating control and energy levels associated with consumption of bitter orange (<em>p</em>-synephrine) extract: a randomized placebo-controlled study

Abstract

Using a placebo-controlled double-blinded 30-day protocol, 40 overweight adults were asked to consume a chocolate-flavored chew 15-30 min before their two largest meals of the day. The chews contained either a placebo or an "active" product (100 mg of a bitter orange extract, standardized to 51.5 mg p-synephrine). Subjects completed a 13-item Weight Control Support Scale (WCSS) containing eating control, energy level, and palatability subscales daily throughout the study. All 40 subjects completed the study. No adverse effects were reported in either the placebo or active groups. As compared to placebo, subjects consuming the active product reported statistically more (p≤0.001) positive responses on the WCSS as well as on each of the three subscales. This study suggests that, as compared to a placebo control, consuming a chew containing bitter orange extract (51.5 mg p-synephrine) 15-30 min before the two largest meals of the day resulted in a statistically significant greater and more positive response to eating/appetite control and a weight-control support scale.

Acute cardiovascular effects of bitter orange extract (p‐synephrine) consumed alone and in combination with caffeine in human subjects: A placebo‐controlled, double‐blind study

“…Ma, Bavadekar, Schaneberg, Khan, and Feller () concluded that p ‐synephrine acts as an antagonist rather than an agonist with respect to human α‐2a and α‐2c adrenergic receptors. The actions of p ‐synephrine are thought to be mediated at least in part by β‐3 adrenoreceptor activation leading to increased metabolic rate, lipolysis, and reduced food intake (Carpene et al, ; Stohs & Preuss, ; Kaats, Mrivichin, & Stohs, ). Thus, our data support receptor binding studies that would indicate a lack of cardiovascular effects due to poor adrenergic receptor binding.…”

“…Kaats et al () administered chocolate‐flavored chews containing 50 mg p ‐synephrine in the form of Advantra Z® (100 mg daily) or placebo 15–30 min before the two largest meals of the day for 15 or 30 days and reported no changes in HR or BP, and no adverse effects were reported. Jung et al () examined a pre‐workout dietary supplement with and without 20 mg of p ‐synephrine and reported no significant changes in HR, BP, and ECG within 30 min of consumption.…”

Safety, Efficacy, and Mechanistic Studies Regarding Citrus aurantium (Bitter Orange) Extract and p‐Synephrine

“…No changes in heart rate or blood pressure were noted, and no adverse effects were reported for either the p ‐synephrine‐treated group (103 mg p ‐synephrine per day) or the placebo control group. Statistically significant increases in energy and appetite/eating control were reported with respect to the p ‐synephrine chew as compared with the placebo control chew (Kaats and Stohs, ). This study again demonstrated the absence of cardiovascular effects when consuming up to 103 mg of p ‐synephrine per day.…”

Effects of <em>p</em>-synephrine in combination with caffeine: a review

“…11 As such, subjects consumed 103 mg p-synephrine or placebo daily. No caffeine was given to the participants, although a majority consumed caffeine on a daily basis.…”

“…Various effects on lipid metabolism, 10,24,25,57 metabolic rate, 52,58 sport performance, 4 and energy production 11 have been demonstrated at these doses, as well as higher doses of p-synephrine that do not produce cardiovascular effects. 4,10,11,24,25,52,57,58 Therefore, adequate blood levels are achieved to produce these effects without cardiovascular effects. The question remains whether cardiovascular effects can be attained at doses of p-synephrine >100 mg. To date, doses of up to 100 mg p-synephrine per day for 60 days have been shown to be without adverse effects.…”