Berry extract that grows on a shrub-like tree. The fruit of this plant contains malic and acetic acids (AHA-like ingredients that give the fruit an astringent, acidic taste) as well as beneficial compounds known as flavonoids, plus fatty acids. Sea buckthorn is a rich source of vitamin C, but most of it is lost when the fruit is processed for production (which includes manufacture for use in cosmetics products).
Sea buckthorn is believed to have several topical benefits, and research is bearing this out, but comparative studies are lacking.
References for this information:
Food and Chemical Toxicology, June 2009, pages 1,146-1,153
PLOS One, April 2012, ePublication