Some protocols use an extended break matching the cycle length (8 weeks on, 8 weeks off)
There is no accumulation concern with either formulation at standard injectable doses
1 2 BMJ
Patients who typically benefit from vitamin B12 injections include individuals diagnosed with vitamin B12 deficiency, those experiencing difficulties absorbing nutrients through their digestive tract, or patients who follow restrictive dietary patterns, such as strict vegetarians or vegans
Furthermore, as hormones can also affect hair growth [60], serum T and E2 levels in the mice were measured using ELISA kits, and the results indicated no significant variations in the T/E2 ratios in mice treated with CaT-ME or CaT, implying that these systems did not alter hormonal homeostasis in mice (Figure S10 and 11)
Medical News Today reports that vitamin B12 injections are only available by prescription and must be administered by a licensed medical professional