It is a great emollient that makes the skin smooth and nice and helps to keep it hydrated. It also protects the surface of the skin and enhances the damaged or irritated skin barrier. According to Leslie Bauman in Cosmetic Dermatology, one application of sunflower oil dramatically speeds up the regeneration of the skin barrier within an hour and maintains the effects for 5 hours.

Helianthus Annuus Seed Oil is also high in fatty acids (linoleic (50%-74%) and oleic (14%-35%)). The unrefined version is particularly high in linoleic acid, which is beneficial even to acne-prone skin. It is non-comedogenic which means it is suitable for all skin types.

See also:
Emollient Fatty Acid
Linoleic Acid
Oleic Acid