Many people notice sleep improvements first, followed by changes in energy, recovery, and body composition over several weeks or months
[DOI] [PubMed] [Google Scholar] 141.lutz ta, geary n, szabady mm, del prete e, scharrer e
[2] For most individuals taking standard B12 supplements as recommended by healthcare professionals, the risk of harmful effects remains extremely low
1,2 Serum vitamin B 12 levels may be artificially elevated in patients with alcoholism, liver disease, or cancer because of decreased hepatic clearance of transport proteins and resultant higher circulating levels of vitamin B 12
You can use B12 injections as a supplement if you feel you are not getting enough vitamin B12 through your food
The only way to know if you have one is by checking in with a healthcare pro to get your vitamin levels tested