Most researchers report initial changes between two and three months, with more substantial improvements visible at four to six months
Additional at-risk groups include: Vegans and strict vegetarians , who may have low dietary B12 intake People with autoimmune conditions , including pernicious anaemia or type 1 diabetes Individuals with gastrointestinal conditions such as Crohn's disease or coeliac disease, which impair nutrient absorption People who have undergone bariatric surgery , which can significantly reduce B12 absorption Long-term users of proton pump inhibitors (PPIs) or H2-receptor antagonists , which reduce gastric acid and impair B12 release from food Those with a family history of either pernicious anaemia or diabetes For these groups, simultaneous monitoring of B12 status and glycaemic markers is particularly important to avoid diagnostic errors
It is not approved for therapeutic use and is intended strictly for laboratory and investigative research purposes
Wilsons disease or copper overload
Here are the best vitamin B12 injection sites for each method: Subcutaneous B12 injection sites Usually, the best places to give yourself a B12 shot subcutaneously are the abdomen, thigh, and upper arm, as you can see in this illustration: Although not shown above, the buttock is another good site for B12 shots
A very rare but serious allergic reaction that causes swelling of the face, tongue, and throat can occur