Get it from the health food store. You can get it online if you cannot find it at your local health food store.

My favorite brand is Lily of the Desert. I have not purchased it from the web site I and referring to below. I just wanted to show you the picture of the product.

Blueduck

http://www.kalyx.com/store/proddetail.cfm/ItemID/28919.0/CategoryID/12500.0/S...