"Neat"application of essential oils simply means applying an oil or blend without using a carrier oil. Typically, this should only be used in acute situations or for short periods of time, but we are seeing more and more that people are applying neat essential oils or blends on a daily basis for a variety of reasons. Many people just pop a roller top on their essential oil bottle and call it a day. But, is it safe?
This is one of those controversial topics within the aromatherapy industry underscored by many safety concerns and the risk of adverse reactions. Personally, I rarely do this save for special circumstances such as blemish spot treatments, minor skin inflammations or small cuts, and burns. Though there are other circumstances when you may desire to apply an oil or blend undiluted -- most aromatherapists and industry experts seem to agree that this should not be the go-to application method for essential oils due to their potency and the risk of adverse reaction by those who are unaware of any known safety issues with a particular oil. Undiluted application should only use 1-2 drops per application in small targeted areas. Robert Tisserand specifically states to never apply essential oils undiluted on the skin. Read more about How to Use Essential Oils Safely and also New Survey Reveals Dangers of Not Diluting Essential Oils
Some people who have sensitive skin or other skin issues should not apply undiluted essential oils to their skin as they may be more prone to having a reaction. Others may never have a reaction to undiluted application. I prefer to err on the side of caution.
There is a reason that the vast majority of essential oils based recipes use some type of carrier oil or blend of oils, butters, waxes, etc. to administer the topical application of essential oils. They are fat soluble and disperse evenly when diluted properly. The fatty oils make oils that are potential dermal irritants or sensitizers safer to use -- this is not to say that you will never have a reaction, but it minimizes the risk. You also need to know proper blending and dilution ratios as using a dermal sensitizer like Lemongrass even with a carrier oil can still cause a dermal reaction.
