In a sick cat, symptoms such as lethargy, loss of appetite, vomiting, diarrhea, and constipation may be partly due to B12 deficiency
Most B12 supplements on the market won't include both and often fail to include methylcobalamin at all, which might present a problem to those who suffer from B12-related polymorphism or other gene-related methylation issues
Elderly Patients Older adults often have reduced stomach acid or atrophic gastritis, leading to poor B12 absorption
Journal of Obstetrics and Gynaecology
The exact mechanism isn't fully mapped out, but it's thought to involve minoxidil sulfate (the active metabolite produced when minoxidil is converted in the body) interacting with follicle cells to delay the transition from anagen to the resting phase
doi:10.1001/jamaoto.2021.4470