MTHFR is linked with hair loss for a number of different reasons. The main reason is that MTHFR is responsible for activating folate and active folate is necessary for the growth and reproduction of cells.  Hair growth requires cells to be able to rapidly divide and in a person with low active folate status, that is not possible. MTHFR is also linked with higher levels of inflammation and oxidative stress, both of which are problems for the health of your hair follicles.