b12 injections given where Shots at Home: How, & How Often to Inject Yourself Vitamin B12 Shot | IV

In fact, a 2008 study found that after taking a 1,000 mcg oral supplement, only approximately 1.3% (or 13 mcg) of B12 was absorbed into the bloodstream

You work hard to reduce body fat, achieve your target weight, and then find yourself dealing with sagging skin that obscures your results

So the practical takeaway is not oral is better or SC is better. It is: pick one route, follow the documented per-dose figure for the vial you have, and keep the route constant so that whatever you observe is not confounded by a mid-stream route change

As such, they could serve as deciding factors in comprehensive weight loss plans