Moro blood-orange extract and weight loss Original paper

In this randomized controlled trial in healthy adults with overweight who were on a calorie-controlled diet and exercise program, the participants who supplemented with a proprietary Moro blood-orange extract lost more weight than those who took a placebo.

This Study Summary was published on June 28, 2022.

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Blood oranges have a reddish flesh and juice colored by anthocyanins, a class of bioflavonoid pigments with red, purple, blue, or black colors. Moro is a particularly pigmented cultivar of blood orange. In vitro (cell culture) evidence suggests that anthocyanins may affect fat cell function and accumulation, and a previous study found that Moro orange inhibited fat accumulation in mice.[1] This study assessed the efficacy of a proprietary extract of Moro oranges on weight loss in adults with overweight.

The study

In this 6-month randomized controlled trial, healthy Australian adults (ages 20–65) with BMIs in the overweight range (25 < BMI < 35; the range specified by the study authors) were assigned to take either capsules containing 400 milligrams of dried Moro orange extract (65 participants) or a placebo (71 participants) daily with breakfast for 6 months. All of the participants were asked to walk for 30 minutes three times per week, follow a calorie-controlled diet, and keep physical activity and food diaries. The researchers monitored participant adherence to the study protocol throughout the 6-month period.

At baseline and study completion, the researchers measured dietary intake, anthropomorphic measurements (i.e., body dimensions), blood parameters, and body composition (as assessed by DXA). At monthly follow-up visits, the participants repeated the body measurements, reported their dietary intakes, and completed a tolerance assessment, with an additional DXA scan at 3 months.

The primary outcomes were weight loss and body composition.

The results

Both groups had reduced weight, waist circumference, and hip circumference at 4 and 6 months, but the Moro group had significantly greater reductions than the placebo group.

At 6 months, the Moro group had lost an average of 4.2% of their starting weight, compared with 2.2.% in the placebo group. Weight loss in both groups was modest due to low diet and exercise adherence.

Additionally, the DXA scan found greater decreases in total fat mass and abdominal fat mass in the Moro group versus the placebo group.


Study dropouts occurred at several points during the study. Of the 180 initial participants, 44 dropped out before baseline measurements were completed. After adjusting for the number of participants who withdrew or were lost to follow-up, 45 participants in the Moro group and 53 in the placebo group eventually completed the study.

This study was funded by the company that produces the proprietary Moro orange extract. The authors don’t appear to have statistically corrected for multiple outcomes.

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This Study Summary was published on June 28, 2022.