Corneocyte maturity plays a crucial role in dermatology and cosmetic science because immature corneocytes in the stratum corneum (SC) can cause impaired barrier properties. This poses a threat to overall health, since it is the outermost layers of the SC that protect the body from invasion by pathogens and viruses.1, 4 Interestingly, studying corneocyte maturity has enabled dermatologists to determine there are no differences in corneocyte maturity across different racial groups. Further, a causal relationship has been found between excessive amounts of immature corneocytes and dry skin in all ethnic groups.2
Since corneocytes act as indicators, they can be used to correlate the age and health of skin. Therefore, the techniques discussed here could be used to determine the efficacy of skin care products. For example, cosmetic scientists have demonstrated that the use of cosmetic moisturizers containing niacinamide and hexamidine help promote the development of mature corneocytes, in turn improving the barrier properties of skin.3 This enhancement of barrier properties is attributed to increased levels of tortuosity and better covalent bonding of the SC to intercellular lipids that protect skin and prevent water loss.