The NHS symptoms list groups them into general anaemia symptoms (tiredness, breathlessness, headaches, loss of appetite, weight loss) and neurological signs (peripheral neuropathy, balance problems, depression, memory and concentration changes, sometimes mood changes or psychosis in advanced cases)
The Honest Answer: B12 Shots Wont Cause Weight Loss on Their Own Vitamin B12 is an essential nutrient
In general, injections are done using a clean, sterile technique: wash hands, clean the skin with an alcohol prep, let it dry fully, and avoid touching the cleaned area before injecting
B12 shots can last as well for people who only need B12