I don't see how you are getting that only 5mcg is lost daily: if you have injected say 1000 mcg of B12, most of it is peed out within a few days
Wegovy has been clinically studied for weight management

vomiting The following Vitamin B12 (cyanocobalamin) side effects have also been reported Side effects that you should report to your care team as soon as possible: Allergic reactionsskin rash, itching, hives, swelling of the face, lips, tongue, or throat Side effects that usually do not require medical attention (report to your care team if they continue or are bothersome): Pros and cons of Vitamin B12 (cyanocobalamin) Pros Can help restore vitamin B12 levels if you're not getting enough from your diet Taken by mouth once per day Available over the counter in many different forms (e.g., pill, gummy, liquid) Cons Not labeled for use in children younger than 18 years of age Many different dosages available, which can be confusing Some forms (e.g., liquids, gummies) contain sugar Pharmacist tips for Vitamin B12 (cyanocobalamin) Discuss with your provider whether you're getting enough vitamin B12 from your diet or if you should take a vitamin B12 (cyanocobalamin) supplement

it will not be effective in cases of primary ovarian failure or primary testicular failure where the glands cannot respond
Understanding these differences helps researchers select the appropriate compound for their specific laboratory protocols
10.1097/00003086-199404000-00046 24 DamienC