Hesperidin is a bioflavonoids glycoside commonly found in citrus fruits (most notoriously oranges) and is a sugar-bound form of the flavonoid hesperitin. Hesperitin is known to mediate the actions of hesperidin in the body, and since hesperidin needs to progress to the colon to be 'released' by intestinal bacteria it acts as a time-release for hesperitin; one serving of hesperidin seems to increased blood levels for over the course of a day or so when consumed in this manner.

Hesperidin has anti free radical activity, promotes blood flow (minorly to moderately) and may have a weak influence on blood pressure while it is pretty much ineffective on cholesterol and triglycerides. Not much other human evidence exists aside from the cardiovascular parameters mentioned above, and it seems pretty weak at improving parameters of diabetes as well (with exception to the eyes, diabetic retinopathy, as preliminary evidence suggests that hesperidin is quite protective of them).