Essential oils are volatile aromatic compounds.   They may react to light, temperature, air and time.

Essential oils are non-greasy and inflammable.  They are volatile at room temperature, thus in use they evaporate leaving no trace.  Essential oils are insoluble in water but soluble in oil or alcohol and need to be diluted in carrier oil to be applied to the skin.   Like an aspirin, they have quick power and know-how to go where  needed.  They have healing properties; assist in the re-balancing of the system; re-enforce the immune system; some are tonics to organs; hormone balancers and excellent skin rejuvenators.

An essential oils has many properties (ie anti-bacterial, anti-inflammatory)  and chemical components (ie alcohol, phenol, ester).

As essential oils are highly concentrated they can irritate the skin when used in undiluted form, as such they should be diluted in a carrier oil prior to topical use.  On average, it takes approximately 20-70 minutes for the essential oils to enter the blood stream.