Furin is an endoprotease that is found inside the cell, on its surface and in the extracellular space. This may explain its ability to process a large amount of different substrates, such as growth factors and cytokines, hormones, adhesion molecules, collagen, metalloproteinases, clotting factors, receptors, membrane channels, and albumin . SARS-CoV-2, like many other viruses, requires furin to penetrate the host cells . Zahra Sheybani and colleagues demonstrated, using molecular simulation, that folic acid and folinic acid form a complex with furin. However, the binding place of these metabolites is not in the catalytic region of furin , therefore they cannot exert a competitive inhibition. This makes sense since if this binding happened in pregnant women taking FA, it could severely affect the furin physiological processes.