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Understanding the difference between an essential oil and an extract is an important first step in building your knowledge of homeopathy, herbs, cosmetics and any other field dealing with natural ingredients. An herb used for many centuries, rosemary is commonly found in both forms. The difference between the two is the manufacturing process and the way each is used.

Rosemary Extract

Rosemary extract is created when rosemary leaves are soaked in a compound, perhaps alcohol, which separates active ingredients from plant matter. The resulting solution can be used as a tonic or tincture for teas and other heath aids. Some people prefer liquid extracts over supplements in powder or capsule form because, according to folklore, they are more effective. Those who ingest rosemary as a dietary supplement do so in hope of a health benefit. A 1999 abstract from a study on the pharmacology of rosemary identified caffeic acid and antioxidants as substances that might deliver healing or cancer-preventing effects.

Rosemary Essential Oil

According to the Natural Ingredient Resource Center, the most common method of producing an essential oil is through steam distillation. In this process, rosemary is placed into a steam chamber that causes the oil to sweat out of the plant. The oil travels from the chamber into a condenser that turns it into a solution of water and oil. The oil strained from the formula is called essential oil. Essential oils from many sources are packaged and sold in stores.

Distillation maximizes rosemary's woodsy, invigorating scent. For that reason, it is commonly used in shampoos, soaps and lotions, and is a staple among aromatherapists. Like most distilled oils, rosemary essential oil should not be ingested; however, it can be used to gain therapeutic benefits. According to the Natural Medicines Comprehensive Database, rosemary is used topically to prevent baldness, improve circulation, ease eczema, heal wounds, repel insects and -- through massage -- relieve pain in the joints.

Differences

Rosemary extract is primarily used as a health aid. Those who believe that this liquid form of rosemary is more helpful than its capsule form add it to teas and tonics, or ingest it alone as a medicinal tincture. In essential oil form, rosemary's primary role is as an aromatherapeutic agent in skincare products. It is also used in massage oils and inhalers to address specific health conditions, such as stress, or to enliven the memory and senses.

Precautions

Both essential oils and extracts are highly concentrated, and users should exercise caution when using them for any purpose. Rosemary in any form might affect you in ways unknown, such as with an allergic reaction. Never swallow essential oil or apply directly to the skin. Use a recipe from a certified aesthetician or qualified aromatherapist when creating homemade products with rosemary.