Castor oil is a byproduct of castor oil production. This is a simple, yet efficient, method for increasing the size of your eyebrows naturally. The oil extracted from the coconut. If you want thicker eyebrows, coconut oil should be at the top of your list of ingredients. Extra virgin olive oil is a preferred cooking oil. Another fantastic home remedy for thicker brows is to use olive oil. Onion juice is used in this recipe. The yolks of eggs. Jelly made from petroleum.