These larger oils that come from the fatty part of the plant can increase the length of time the essential oils stay on your skin and also prolong the aromatherapy effects.
Some people mistakenly think using carrier oils reduces the effectiveness of the oil but really it can be the opposite. Dilution increases the surface area of absorption and with certain oils can prevent sensitivities.
Common carrier oils include:
Pomegranate seed oil
For most people, I recommend 10 percent dilution, which is five drops of oil per half-teaspoon.
Source: Dr. Josh Axe