The first thing you're often told when beginning to work with essential oils is that they must always be diluted. This is generally true, and for good reason. Essential oils are highly concentrated substances that can irritate or sensitize the skin if used improperly. However, there are cases, both in natural perfumery and aromatherapy, where undiluted (or “neat”) application is appropriate and even desirable.
This brief guide is meant to offer clarity on when and why neat application may be used, and how to approach it safely and thoughtfully.
When Is Neat Application Appropriate?
Not all essential oils are suitable for undiluted use. If you wish to apply oils directly to the skin, choose the gentlest and safest ones, those known for their skin compatibility and, ideally, GRAS (Generally Recognized as Safe) status. Oils such as lavender, petitgrain, chamomile, vetiver, patchouli, sweet marjoram, coriander, cypress, clary sage, and geranium are among the more forgiving options. Yet even with these, it’s essential to perform a patch test, especially if you have sensitive skin, allergies, or are unsure how your body might react.
Keep in mind that phototoxic oils, like many cold-pressed citrus oils, should never be used undiluted before sun exposure, and that some essential oils are entirely contraindicated for children, pets, or during pregnancy and breastfeeding. The familiar and “safe” oils may still trigger unexpected responses, because skin is personal, and reactivity varies from person to person.
In aromatherapy, a common instance of neat application is spot treatment, when a single drop is applied to a very small, localized area of the skin, such as a blemish, a cold sore, or a sore muscle. This method must never involve application to mucous membranes, broken skin, or any inflamed area where the oil could worsen the condition. The logic behind spot application is that the quantity is very small and the exposure highly targeted, minimizing risk while offering a concentrated effect.
In natural perfumery, you may also work with undiluted oils to create attars or oil-based perfumes that contain no carrier oils or alcohol. These are typically made with precious ingredients like sandalwood, rose, or jasmine, and are dabbed lightly on pulse points in minuscule amounts. Their purity enhances both their aromatic clarity and ritual elegance.
Similarly, in spiritual and ritual practices, neat or lightly diluted oils may be used for anointing or palm inhalation. This might involve placing a single drop on your palm, rubbing the hands together, and gently cupping them over your nose to breathe in the aroma. This can be done for therapeutic, emotional, or symbolic purposes. When the session is complete, simply washing your hands is enough to remove the scent, which is especially helpful for those with sensitive noses or a low tolerance for lingering aromas.
How to Perform a Patch Test
Before using any new essential oil or blend, apply a small amount (properly diluted) to the inside of your elbow or wrist and wait 24 hours. If no irritation or redness occurs, it’s likely safe for topical use.
Understanding the Type of Reaction
It’s important to distinguish between irritation (an immediate burning or stinging sensation), sensitization (a delayed allergic response), and phototoxicity (a reaction triggered by UV light after applying certain oils). Understanding the type of reaction helps guide the appropriate response, for example, removing the oil with a carrier instead of water, or avoiding sun exposure.
How to Respond to a Reaction