There are two types of oils to consider in formulations: essential and carrier. You cannot really formulate a spray from 100% oil unless perhaps you're just interested in a massage oil. When you combine them with purified water, you face a problem, which is called 'emulsion'. An emulsion is not only important for combining water and oil, it is essential for allowing the carrier oils to protect the volatile EO's from almost instant oxidization as a result of exposure to oxygen. So we see, an emulsion can not only slow the oxidization of the EO's, it can facilitate the homogeneous dispersion of the product on the skin. If a product is not emulsified and the ingredients are temporarily mixed by vigorous shaking prior to spraying it, then they separate again as soon as they are dispersed on the skin, and the EO's begin rapid oxidization while leaving the carrier oils to pool in their own demographics. In this state, the product's effectiveness, no matter what the inherent properties of the individual EO's may posses, is rapidly diminished. The proprietary formula our Herbal Spray emulsion, which is made in Canada, has been evolving for fifteen years, and is still being fine tuned. For example, due to the publication of recent research papers, 2014 saw the addition of Evening Primrose Oil. White Tea extract was also recently added to the formula. Use the 'Ingredients' link on the left sidebar for more information about each ingredient.