With tons of mascara out there, both waterproof and not, I always assumed personal preference was the driving force behind purchases. I have a pal who purposely stocks a water-repellent tube during the cold months (and for sappy movie dates) whereas others wear only waterproof even on happy days. So, what's the big difference?
Well, as I embarked on my latest research mission, I hoped for an easy answer . . . but no dice. It seems likely that what makes makeup waterproof is the presence of fats, oils, or waxes, as all three of those are hydrophobic — that is, resistant to moisture. (It makes sense that cosmetic companies would keep exact mixtures a secret, as competitors would want to include whatever worked best.)
Tackling just the first five ingredients in each product, I found a few differences. In its top five ingredients alone, the waterproof version had three waxes (beeswax, candelilla wax, and carnauba wax), water, and isododecane, a mixture of highly branched isoparaffins. However, the regular Diorshow had only one wax in the top five (beeswax). In this case, speculation proves true: Wax helps this waterproof mascara stand the test of time.