This is a lot of mis-information on this topic around and some very strange claims too! It is true that pure essential oils do not go rancid, but they will, however degrade in their therapeutic benefit over time. The rate of degradation varies by the type of oil, but generally the lighter citrus oils will oxidise faster than the thicker and more resinous oils, like sandalwood or frankincense.

The producers and distributers from whom we source our essential oils all supply great products that are GC (Gas Chromatography) and MS (mass spectrometry) tested to ensure that the products are 100% pure and contain the constituents expected in a particular oil, but they all have expiry dates for each batch they produce.

A lot of our essential oils are used on the skin and some are taken internally - using old essential oils could potentially cause skin irritation and in most countries, anything that is sold as a product that can be consumed must contain a use by date. We would never chance our customers health by not giving an indication of when the oil should be used by.

There are a number of informative websites on this, I have attached links to a couple below (the first talks about lots of EO myths, including why EO’s need expiry dates):

It would be much easier for us not to use expiry dates, but we believe that this is wrong as people cannot guarantee the effectiveness of the essential oil if they don't know how long it has been sitting in someone’s warehouse for!

I hope that helps. Please let us know if you have any questions!