The best mascara for long eyelashes have less dense formulas. They also have wands with shorter bristles that are packed more tightly than most wands.
The formula is important for lengthening eyelashes because the mascara needs to go on smoothly and cover the eyelashes evenly from the root all the way to the tip. Building eyelashes at the tip is the most important factor in long eyelashes.
The wand is important for making sure that the eyelashes are thoroughly and evenly covered. The wands of the best mascaras for long eyelashes have bristles that are designed specifically for completely covering each lash in mascara.