are b12 injections given im or subq Sublingual vs. B12 Injections: Which Option Is Right for You? – WhyNotNatural Best Vitamin B12 Injection Site:

The exact timing is completely personalit all depends on your bodys unique response, any underlying health issues, and how quickly you use and store Vitamin B12

Vitamin B12 shot side effects Most people tolerate vitamin B12 injections well, but possible side effects include: Mild: soreness or redness at injection site, mild diarrhea, nausea, headache, itching Rare but serious: allergic reactions (rash, swelling, difficulty breathing), low potassium (hypokalemia), dizziness or heart rate changes Get emergency medical help if you have signs of an allergic reaction to Vitamin B12: hives

A mild, short reaction is common and recognised

How long does a vitamin B12 injection last

Nanomedicine 11 , 235247 (2016)

Hill, T