Three RCTs (two parallel and one cross-over) were included in the review (208 participants, range 72 to 120). None of the trials reported appropriate randomisation or allocation concealment. No RCTs reported outcome assessors as being blinded; two RCTs, patients and care provider were blinded. One RCT did not have similar characteristics at baseline. None of the RCTs performed an intention-to-treat analysis or reported sample size calculation or attrition.
All three trials reported a statistically significant reduction in body weight with Irvingia gabonensis compared with placebo (12.8kg versus 0.7kg; 4.1kg versus 0.1kg; 11.9kg versus 2.1kg). Significant weight loss continued up to a 10 week period (>5% from baseline). Two RCTs reported significant reductions of body fat with I. gabonensis compared with placebo (6.3% versus 2.0% and 20.1% versus 4.0%), but one RCT did not.
All RCTs reported statistically significant changes in waist circumferences with I. gabonensis (-16.2cm versus -53cm; -6.2cm versus +5.5cm; -21.9cm versus -1.0cm). One RCT reported significant reduction in hip circumference with I. gabonensis (-4.5cm versus -0.7cm) compared with placebo.
All RCTs suggested positive effects of I. gabonensis on the blood lipid profile.
Two RCTs reported adverse events including headache, sleep difficulties, and flatulence. There were no significant differences between Irvingia gabonensis and placebo for adverse events.