An alternative to traditionally-used vegetable esters, Silybum Marianum (Milk Thistle) Ethyl Ester contains over 50% linoleic acid (from the omega-6 family). And because linoleic acid is naturally present in our skin, applying Milk Thistle to the skin reinforces the skin’s innate ability to protect itself against physical and chemical stressors, dryness and moisture loss.Milk Thistle ethyl ester also contributes to the luxe, soft touch and feel of Story’s bestselling Serum.