Serum is the blood component that is obtained after coagulation and removal of cellular components. Besides serum proteins, it contains, e.g. growth factors, amino acids, and hormones. This complex mixture makes serum one of the most important supplements supporting the cells growth and proliferation for in vitro cell culture. Of special interest is the Fetal Bovine Serum (FBS). It is especially rich in growth factors and is particularly low in antibodies, which may negatively influence the cell culture work. It supports most cell lines and undergoes strict quality controls. Fetal Bovine Serum Charcoal Stripped is produced by filtering FBS through an activated carbon absorbent filter, resulting in reduced concentrations of steroid hormones, such as estradiol, progesterone, cortisol, testosterone, T3 and T4 without unspecific loss of other serum components. This product is useful for studying processes influenced by steroid hormones (estrogen stimulation, obesity process) and other research topics that benefit from reduced hormone levels, such as certain types of viral infections.