Media optimization is highly recommended for perfusion processes. Customized media can be designed with the right balance of components appropriate for high cell density cultures. Every process may require a different balance of nutrients for production, but for N-1 perfusion, it is likely that a base media with specific supplementation works well to achieve the goal of increasing cell density while avoiding accumulation of toxic metabolites for the cells. For production perfusion, the optimization may need to include additional supplementation to maintain growth and achieve the desired product quality.