Carrier oils are used to dilute and make blends from essential oils. They help the blend extend and last longer. The oils, such as marula and red raspberry, help soften the skin and promote elasticity. Use 10 drops or more of essential oils in 1 ounce of carrier oil. Maximum doses are 20-30 drops of essential oils in 1 ounce of carrier oil. Blends last 6-8 months kept away from heat and light. For more information read Flowers that Heal by Judy Griffin, PhD.