Castor oil is considered the best lash oil for growth. In addition, you should pay attention to olive oil, which also helps eyelashes. Eyelash growth serum with olive oil is a safe and effective way to activate the growth of eyelashes, make them voluminous and healthy. With consistent use (i.e. weeks, and sometimes months)—and the right formula for your needs—you should be able to see positive results. “Lash growth serums work to strengthen, nourish and condition the eyebrow hairs which may give the hairs a thicker and toplash nyk1 lash serum reviews healthier appearance,” Garshick explains. “By improving the health of the lash hair, it may also help make it less susceptible to breakage.” Is castor oil or coconut oil better for eyelash growth?In the battle of the oils, this is the one that has us at the edge of our seats. When they go head to head, coconut and castor oil tend to fight it out to the bitter end with their similarities far out-weighing their differences.