Essential oils don't spoil like food does, but they do change over time. Because it's hard to determine what the oils have changed into, it's also hard to determine whether or not they're safe to use. The bottom line is, don't inhale expired essential oils or use them on your skin after they have expired.

How many years do essential oils last?

Most will last at least two years before starting to degrade, unless they contain one of the unstable carrier oils mentioned earlier. And some can last for as long as 15 years without losing their effectiveness. Many experts advise replacing essential oils every three years to be safe.

How long are essential oils good for once opened?

Essential oils expire anywhere from one to eight years from when they were first opened before expiring.