Corn Starch

Zea mays (corn) starch is quite literally the starch derived from varietals of corn. As a skin care ingredient, it's most famously used as an absorbent that lends mattifying properties (helpful for controlling oily skin) and is also popular in makeup powders where it lends a dry yet silky feel and can be lighter on skin than some grades of talc. Zea mays (corn) starch can also be incorporated to increase the viscosity of cosmetic solutions (similar to how corn starch is used in cooking to thicken food). In additional capacities, it is blended with other ingredients to create film-forming properties on skin.

Zea mays (corn) starch may also be used as an abrasive agent, such as you might find in manual exfoliating products. When formulated in this way, there's potential for skin sensitization due to the abrasiveness and uneven shape of particles. Interestingly, topical starches, such as corn starch, are classified as skin protectants under the U.S. FDA monograph when formulated as an OTC (over the counter) active. This means they serve to protect skin from harmful stimuli and provide relief to compromised skin.

These varying roles demonstrate that how an ingredient is incorporated into a formula plays a major factor in overall efficacy, aesthetics, functions, gentleness, and benefits. In their 2013 report, the Cosmetic Ingredient Review Expert Panel surveyed 278 personal care products containing Zea mays (corn) starch ranging between 0.00002-99% concentration. Based on their analysis, Zea mays (corn) starch is safe in these cosmetic practices of use.