What can I do if low molecular weight proteins are not showing any bands in western blot?

For proteins of low molecular weight (<20 kDa), it is possible for bands to not show in a western blot due to poor retention of the membrane and risk of over-transfer. This can be remedied by reducing the voltage or time for transfer, using a PVDF membrane instead of nitrocellulose, and using a membrane of smaller pore size (0.1-0.2 um). A heat-mediated blotting technique or semi-dry transfer can also be beneficial when working with low molecular weight proteins.