Black currant (also known as quinsy berry) is a deciduous bush native to northern regions of Europe and Asia. Categorized in the same genus as gooseberry, red currant, and American currant, black currant grows in moist soils and reaches roughly 2 to 2 1/2 meters in height. The leaves are alternate, with three to five doubly-serrate lobes. Black currant flowers in April and May, bearing clusters of greenish-white blossoms that eventually give way to dark brown, blueberry-sized fruit, which turn black as they ripen. Oil derived from the seeds is used for health purposes.
Although roughly 47 percent of black currant seed oil consists of the omega-6 essential fatty acid linoleic acid, its 17 to 19 percent gamma linolenic acid (GLA) portion is believed to be the oil's most active component. The oil also contains approximately 25 percent alpha linolenic acid and 9 percent stearidonic acid, two omega-3 fatty acids that may contribute to the oil's activity.
Recommended dosages for black currant seed oil vary widely with intended applications. Black currant seed oil has no known toxicity, and as much as 6 grams per day have been used in human trials with no serious adverse effects.