Translation guide
Essential oils are concentrated plant extracts used in aromatherapy, cosmetics, and natural remedies. In Japanese, the term is usually expressed with a direct loanword or a native compound.
The learner wants to refer to essential oils in general, such as in aromatherapy or skincare.
I put lavender essential oil in the aroma diffuser.
A direct loanword from English, common in beauty and wellness contexts.
This essential oil is gentle on the skin.
Often used interchangeably with essential oil, especially in aromatherapy contexts. Note that some products labeled アロマオイル may be synthetic fragrance oils.
You can relax with aroma oils.
The learner wants to name a particular essential oil, like tea tree or peppermint.
Attach の精油 to the plant name. For example, ティーツリーの精油 (tea tree essential oil).
Tea tree essential oil has antibacterial properties.
Also common, especially in product names.
I bought peppermint essential oil.
精油 (seiyu) is the most accurate term for pure essential oils. アロマオイル (aroma oil) often implies a diluted or synthetic product. エッセンシャルオイル is a direct loanword and widely understood, but may sound slightly more commercial or trendy.