The citrus flavonoids hesperidin and naringin have been suggested to lower blood total (TC) and LDL-cholesterol (LDL-C) both in animal models and humans. However, the evidence from previous studies in humans is not convincing. This study evaluated the LDL-C-lowering efficacy of pure hesperidin and naringin in moderately hypercholesterolemic individuals. A total of 204 healthy men and women with a serum TC concentration of 5.0-8.0 mmol/L participated in a randomized, placebo-controlled, parallel trial with 3 groups. A 4-wk preintervention period during which participants refrained from consuming hesperidin and naringin sources preceded the intervention. During the 4-wk intervention, the participants applied the same dietary restrictions and consumed 4 capsules/d providing either placebo (cellulose) or a daily dose of 800 mg hesperidin or 500 mg naringin. Blood samples to measure serum lipids were taken on 2 consecutive days at the beginning and end of the intervention phase. One hundred ninety-four participants completed the study. They maintained their prestudy body weights (mean changes lt 0.2 kg in all groups). In all groups, the mean consumption of scheduled capsules was gt 99%. Hesperidin and naringin did not affect TC or LDL-C, with endpoint LDL-C concentrations (adjusted for baseline) of 4.00 +/- 0.04, 3.99 +/- 0.04, and 3.99 +/- 0.04 mmol/L for control, hesperidin, and naringin groups, respectively. These citrus flavonoids also did not affect serum HDL-cholesterol and triglyceride concentrations. In conclusion, pure hesperidin and naringin consumed in capsules at mealtime do not lower serum TC and LDL-C concentrations in moderately hypercholesterolemic men and women.