Red blood cells carry oxygen to every part of the body
Because absorption is limited, raising serum B12 with pills is a gradual, cumulative process that can take weeks or months of consistent daily use
Importantly, serum B12 levels can be misleadingly normal or even elevated in chronic liver disease due to increased levels of binding proteins (such as haptocorrin) and reduced clearance, meaning that total B12 measurements may not accurately reflect tissue B12 status or functional deficiency
If youre also dealing with low testosterone symptoms alongside B12 deficiency, this guide can help you identify what to watch for
The 2024 NICE NG239 guideline on vitamin B12 deficiency in over-16s lists the main groups who need injections: Autoimmune gastritis (pernicious anaemia)
Slower titration is worth considering if: Nausea persists beyond 2 weeks at your current dose You experience significant GI symptoms that interfere with daily function Your body aches or muscle pain are severe You are losing weight faster than 1 to 2 percent of body weight per week (too-rapid weight loss increases muscle loss risk) Some researchers use a 6 or 8-week interval between dose increases instead of the standard 4 weeks
