Do Essential Oils Expire? - Naturally Blended

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Naturally Blended

Do Essential Oils Expire?

By: Retha Nesmith, Certified Aromatherapist

I recently read a post about whether or not essential oils expire. In the post I read, the author stated that pure essential oils do not expire. They said that essential oils don’t grow mold, mildew or yeast because they do not contain water and have antiviral and antibacterial properties. All of this information is true. What the author left out is how outside properties can indeed affect essential oils.  Proper storage is imperative.

There have been many studies done on this subject. It turns out that there are three main things that can change an essential oil. But before we talk about those things I just want to make sure everyone knows exactly what an essential oil is.  An essential oil is a concentrated hydrophobic liquid containing volatile aroma compounds from plants. These volatile aroma compounds are chemical constituents that make up the essential oil. These chemical constituents are the therapeutic properties of the oil. For example, Peppermint is very high in the chemical menthol. Menthol has a ‘cooling effect’. It also has analgesic properties or pain relieving properties. If Peppermint didn’t have menthol in it then it no longer would be one of the top oils for reducing fevers and relieving discomfort. 

So what are these three outside forces that can change essential oils? They are oxygen, heat and light.

Oxygen!oxygen can change the chemical composition of an essential oil by reacting with some of the constituents.”-Essential Oil Safety. If oxygen is changing the chemical composition of an essential oil, then we no longer know what chemicals are in that oil unless the oil gets another test. Just like the example I gave with Peppermint, some oils might no longer be good for what they were originally good for. This oil maybe hasn’t “expired” but we might want to be aware of this so we don’t continue to use it for a purpose that won’t do any good. One study showed that the “monoterpene content of Lemon essential oil decreased from 97.1% to 30.7% in 12 months when the oil was stored at 77 degrees F with the cap removed for three minutes every day. However, storage at 41 degrees F, with the cap removed for three minutes once a month results in minimal degradation.”- Essential Oil Safety.  So Lemon had not expired because it was still a great oil, just a completely different oil then what it was probably originally purchased for.


Heat! Not enough research has been done on heat causing degradation as much as oxygen. However,  there have been a few studies showing that extreme heat can change the chemical make up of an essential oil.


Light!Light will promote the formation of oxygen free radicals, which are highly reactive.” One study done on Orange Sweet shows that when it was exposed to UV light at 68 degrees F for 50 minutes it’s composition changed dramatically. Multiple chemicals increased, many chemicals decreased and there were even 12 NEW chemical constituents found within the oil.


Maybe essential oils don’t “expire” but they should have a shelf life. This is to make sure you are getting the most out of your essential oils. Maybe they don’t mold or grow mildew but they do change. If you are not aware of these extreme changes and store the essential oils incorrectly, then you might be using an oil that is not what you really think it is.


Download: Plant Therapy Shelf Life Charts


*For more information on how to store your oils and how long Plant Therapy guarantees our oils, please check out our FAQ section.

22 thoughts on “Do Essential Oils Expire?”

  1. Thanks! So if I have peppermint oil in pills (they have an enteric coating) and they are kept in a bottle, are those protected enough from oxygen and light not to degrade?

  2. So if I bought an oil from a company ( it wasn’t plant therapy bytheway) and testing shows my particular bottle was tested two years ago should I return the oil? Is it normal to sell bottles of oil that are 1-2 years old already? Do you think it’s still therapeutic?

    1. Honestly, you would need to ask the company you purchased the oils from as there are many factors that would contribute. It would also depend on the oils in question, as different essential oils have different shelf lives.

  3. Hi. I’ve been hesitating on getting a diffuser for a long time. I know I don’t want a water humidifier one because of the mold issues in this house. But I wonder if a glass one with a candle underneath it will work ok.. I used a butter warmer with a tea candle and the oils evaporated extremely fast.. Does the heat make the oils unsafe in any way? I’m ill and care about the safety aspect. I could save up and get a more expensive diffuser made of glass and wood that doesn’t hold water, but the candle one is sooo pretty.

  4. i just got a lavender small dark bottle so i guess that will protect it form the light?
    one thing i noticed is that it said that it expires on feb 2017…
    i read above it says that the shelf life of lavender is 3-4 years, so does that mean that after I open it i have 3-4 years to use it or the product was made 3-4 years ago since the expiration date is 2/2017?

    1. Thank you for your question…we don’t put an expiration date on our bottles, as variances in storage from person to person can vary greatly, so can shelf life. There is a batch code, which can help in determining information about the oil. We do guarantee quality of oil for at least 1 year from time of purchase, if stored properly. If you have further questions please contact our customer service, who will be happy to help. thanks!

  5. I’m blending some essential oils for anti aging. Is is okay to put the mixture in a bottle with a pumpt dispenser or should I put is in a bottle with a dropper cap? I dont know if air will get into the pump dispensing bottle.

    1. If you’re wanting to store it long term I would recommend using a cap, if you’ll use it relatively quickly I think that a pump is perfectly fine.

  6. was planning to diffuse some sweet orange in my car until I read this article. Since the car will be subjected to sunlight and heat in the day, is it a good idea to use sweet orange in the car? I live in a place that is summer all year long and the car does get heated up quite a bit when we park outdoor. Thanks!

    1. I think you’re fine to use the orange in the car – however I wouldn’t recommend keeping the bottle in the car all day, or for long periods of time. Instead carry it with you in your bag or purse.

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