With few exceptions, all steam distilled essential oils have a shelf life of at least 2 years, and even longer when stored properly. Tea Tree, Pine and Fir oils are the above exceptions, and typically have a shelf life of around 12 to 18 months due to certain components in their natural chemical composition.
Cold pressed citrus oils have the shortest shelf life of all essential oils due to a high proportion of components called terpenes which are more prone to oxidization, therefore extra care should be taken to store them safely away from sources of heat. You can expect citrus oils to remain in good condition for 9 to 12 months, and even longer when cared for properly.
Due to their natural chemical makeup, essential oils don’t turn rancid like vegetable oils; they simply degrade gradually into a state where the therapeutic properties become diminished. Your nose will tell you that something is wrong long before the point when the oils become unsuitable for topical use.
*For informational purposes only. These statements have not been evaluated by the Food and Drug Administration. This is not intended to diagnose, treat, cure or prevent any disease.