For most people, the practical approach involves working with a healthcare provider to establish a baseline through blood work, then adjusting session frequency based on symptom improvement and lab results
A board-certified physician will review your answers, and prescribe B12 shots if appropriate
Avoid applying strong vitamin C products, high-concentration retinoids, or low-pH chemical exfoliants at the same time as AHK-Cu
If you have a temporary deficiency or increased requirement (say, after a surgery or during recovery from an acute illness), you might only need a short course, perhaps a few weeks of injections, until your vitamin levels normalize or you can meet your needs by mouth again
Fill the syringe with B12 and remove the cap from the needle