Growth factors and supplements are bioactive molecules added to cell culture media to promote cell growth, differentiation, and survival. These include proteins like epidermal growth factor (EGF), insulin, and fibroblast growth factor (FGF), which are crucial for stimulating specific cellular processes. Supplements may also include lipids, amino acids, or vitamins, depending on the cell type and research requirements. They are essential for supporting specialized cellular functions and improving culture outcomes.