Although some essential oils oxidize and/or lose their beneficial properties in as short as six to twelve months (eg. most citrus oils), others can actually mature and improve with age and their therapeutic properties can remain intact over a period of many years (eg. myrrh, sandalwood).
Aromatherapy oils do not become 'rancid' like their plant and nut based carrier oil cousins, however they do deteriorate and lose their aromatic qualities and, hence, therapeutic value over time.
Regardless of how long any given essential oil is expected to remain stable, it will achieve its maximum shelf life and maintain its therapeutic value from correct storage and handling.
The basic rules for correctly storing essential oils are as follows:
Store essential oils out of direct sunlight in a cool, dark place, preferably in amber glass bottles.
For maximum life, essential oils can be stored in the refrigerator.
Do not expose essential oils to heat or light, or they will very quickly deteriorate.
Larger quantities of essential oils should be decanted into smaller quantities for immediate use, storing the remainder in a closed glass bottle in the refrigerator.
Do not store essential oils in plastic containers as they may react and melt the plastic and/or cause toxins or impurities to seep from the plastic into the oil.
Ensure an orifice reducer is fitted to the bottle to minimize your aromatherapy oil's exposure to air.
Rubber dropper bulbs should not be stored on essential oil bottles. Essential oils are highly concentrated and may 'cook' the rubber, causing impurities to leach into and spoil the essential oil.
FDA Statement: These statements have not been evaluated or approved by the FDA. Our products are not intended to diagnose, treat, cure, or prevent any disease and are not to be used as an alternative to appropriate medical advice. Consult a health care professional if you are pregnant or have a serious medical condition. This information is for educational purposes and no claims are hereby made as to the medicinal value of these products.