Naringin is a flavanone glycoside. It is a major flavonoid in grapefruit and gives the grapefruit juice its bitter taste. It is metabolized to the flavanone naringenin in humans. Both naringenin and hesperetin, which are the aglyconesof naringin and hesperidin, occur naturally in citrus fruits.

Studies have shown that naringin has a cholesterol-lowering effect, reduces LDL oxiation and can help to prevent hypercholesterolemia. Gorinstein S et al of the The Hebrew University-Hadassah Medical School, Jerusalem, studied the changes in plasma lipid and antioxidant activity in rats as a result of naringin and red grapefruit supplementation. They found that diets supplemented with red grapefruit juice and to a lesser degree with naringin improved the plasma lipid levels mainly in rats fed cholesterol and increased the plasma antioxidant activity. They concluded that naringin has plasma lipid lowering and plasma antioxidant activity increasing activity.

Naringin is an aldose reductase inhibitor which means that it can help to fight retinal disease linked to diabetics.