Effectiveness of Estee Essence After Being Left Open

Leaving the cap off your Estee essence for about 2 hours is unlikely to significantly reduce its effectiveness. Most cosmetic products are formulated to be stable under normal conditions, and a short period of exposure to air should not cause major degradation. However, it is always best practice to keep cosmetic product lids tightly closed when not in use to prevent potential contamination, evaporation of volatile ingredients, and degradation from prolonged exposure to air and light. For future use, ensure the cap is closed properly to maintain the product's quality over its shelf life.