As noted, patchouli is considered a classic cosmetic oil for skin that is oily, blemish-prone, or easily irritated. It is critical to dilute this pure essential oil before applying it to your skin to avoid irritation or sensitization.
A general guideline for facial application is to add a single drop of patchouli oil to about a teaspoon (5 ml) of a carrier oil like jojoba, grapeseed, or rosehip seed oil. This creates a roughly 1% dilution suitable for facial use. After dilution, patch test first: apply a small amount to the inside of your forearm and wait 24 hours to check for any adverse reaction. If none occurs, you can incorporate the diluted blend into your routine. Common methods include using it as the last step in your evening routine, applying a few drops to cleansed skin, or mixing a drop into a dollop of your unscented moisturizer. Since essential oils are potent, consistency with a small amount is better than frequent high-dose use. This product is for external use only; avoid the eye area. If you have a history of very sensitive skin or strong reactions to essential oils, extra caution is advised. It is not a substitute for a balanced diet or medical treatment for skin conditions.