Agarwood oil, or oud, is a complex oil which has many unidentified compounds. Due to its rarity and price, adulteration is common. True, pure oud oil is very uncommon in the market. Several components present in agarwood oil are easily available for purchase, such as benzyl alcohol and benzyl acetone. Solvents may also be added, such as Dipropylene Glycol (DPG). The ease of purchasing these components and solvents makes adulteration even more common.
Oud oil has several sesquiterpenes, so heavier oils may also be added, such as cedarwood and vetiver oil. It has many fatty acids as well, so cooking oil is the most common adulteration. Due to heavier components being present, this oil necessitates a GC-MS test to determine purity. Some fatty acids are naturally present in Agarwood EO, so the addition of carrier oil can make adulteration detection confusing. Like some other oils, consistency is another challenge in agarwood adulteration.