Equilenin impurities refer to the various by-products or contaminants that can be found in equilenin, a steroid hormone commonly used in hormone replacement therapy. These impurities can affect the efficacy and safety of equilenin-based medications, and therefore must be carefully monitored and controlled during the manufacturing process. Analyzing and removing equilenin impurities is essential to ensure that patients receive the highest quality and most effective treatment possible.