Solgar Ester-C Immune Complex: Contains 7 immune supportive nutrients scientifically shown to support the immune system Vitamin C in the Ester-C form is retained by immune cells for up to 24 hours & is important to immune cell function Provide Vitamin D in the active D3 form Healthy mucous membranes are supported by Vitamin A & Biotin Supports first line defences with Vitamin A & Zinc that support skin barrier function