Most B12 deficiency is due to malabsorption, not lack of B12 in the diet.

But a person who absorbs normally will develop a deficiency if no animal products are eaten (unless supplements are taken) for many years.

I have not yet looked into the patch, but I know from much research and experience that a reputable brand of oral B12 will work (even for those who malabsorb severely if at least 1000 mcg doses of immediate-release B12 are taken).

Those who are certain they absorb normally can take a much smaller dose.

rose