The challenges of incorporating retinol in cosmetics.

• Insoluble in water: Being a fat-soluble vitamin, it is not soluble in water.

• Sensitivity to inactivation: Highly active, extremely sensitive to light, temperature, oxygen, etc., making it prone to losing its activity.

• Inconvenient handling: Handling is inconvenient due to the need for inert protection.

• Irritating: High concentrations of Vitamin A can cause skin irritation.

• Prone to yellowing products: The application of retinol in products can lead to yellowing.

• Poor penetration and absorption: With a large molecular weight, it is not easily absorbed through the skin, resulting in low bioavailability.