Naringin belongs to the group of flavonoids. Pure naringin is a yellowish powder. Naringin is a conjugate of a sugar molecule with naringenin. The structure of naringin is very similar to that of hesperidin. Naringin is mainly found in grapefruits (sweet orange). It is the compound that gives grapefruit its typical bitter flavour. Naringin has antioxidant, anti-carcinogenic and cholesterol lowering activity.

Studies have shown that naringin has a cholesterol-lowering effect, reduces LDL oxidation 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. Naringin (and grapefruit) can interfere with certain drugs including calcium channel blockers, sedatives, cholesterol lowering drugs, caffeine and estrogen. Naringin stimulates the effect of caffeine and could therefore increase its fat burning action.