Biotin is a kind of natural pill that helps to increase the growth rate of the hair, thus, it is also very effective in lengthening your eyelashes. This natural ingredient is part of the Vitamin B family and the pill will not only make your lashes grow longer but it helps to make your hair, nails and skin to be healthy as well. You can purchase this pill from any drug store in your area. It is packaged in a bottle which contains directions on the proper usage of the pill. Or, biotin can be found in nuts, eggs, and avocados. Tip from The Cherry Share.