injections of vitamin b12 are used successfully to treat The Truth About Injections: Benefits, Cost & How They Work Vitamin B12 Deficiency in Aging:

Typical Dosage Range Most men with low vitamin B12 levels receive around 1,000 mcg per injection, depending on their blood levels and health goals.( 9 ) However higher doses, as much as 2,000 mcg can also be safe in some cases

doi:10.1053/j.gastro.2012.01.035 79Plevris N, Lyons M, Jenkinson PW, et al

Dietary management becomes essential on tirzepatide, not optional

Many studies show that people dealing with depression could benefit significantly from vitamin B12 supplements in combination with anti-depressants

Oral supplements might work for some, however, as we age, our ability to break down oral supplements often decreases