Vitamin B12 Injections
Oral B12 doesn't work for everyone.
B12 absorption requires intact stomach acid and a protein called intrinsic factor. For patients with low stomach acid, gut dysfunction, or certain medications, oral B12 supplementation is poorly absorbed — regardless of dose. Intramuscular injection delivers B12 directly.
B12 deficiency is more common than most doctors check for.
Vitamin B12 is essential for nerve function, red blood cell production, DNA synthesis, and neurotransmitter production. Deficiency is associated with fatigue, brain fog, peripheral neuropathy, mood changes, and anemia. The standard lab lower reference limit (200 pg/mL) is too low — most patients feel significantly better above 600–800 pg/mL.
Absorption is the key variable. Patients on proton pump inhibitors (omeprazole, pantoprazole), metformin, or with low stomach acid (common with age) may not absorb oral B12 adequately — even from high-dose supplements. Intramuscular injection bypasses the GI tract entirely.
Our Approach
Methylcobalamin — the active form.
We use methylcobalamin, not cyanocobalamin. Methylcobalamin is the neurologically active form of B12 — it does not require hepatic conversion and is retained in tissues longer.
Intramuscular Injection
Direct delivery to muscle tissue. Absorbed into the bloodstream without GI involvement. Used for patients with confirmed deficiency, poor oral absorption, or rapid repletion needs.
Dosing and Frequency
Loading doses (typically weekly for 4–8 weeks) for patients with significant deficiency, followed by maintenance injections monthly. Frequency adjusted based on how your lab values respond.
Who Benefits
B12 injections are most appropriate for:
Patients on PPIs or metformin
Both medications significantly impair B12 absorption. Patients on long-term PPI therapy are at high risk for B12 deficiency even if their levels appear adequate on standard labs.
Patients with gut dysfunction
Low stomach acid, Crohn's, celiac, or post-surgical GI changes impair the absorption pathway that B12 requires.
Patients with documented deficiency
B12 below 400 pg/mL combined with symptoms warrants more aggressive repletion than oral supplementation can typically achieve.
Patients who have tried oral B12 without results
If oral supplementation (even high-dose sublingual) hasn't moved your levels or symptoms, injection is the appropriate next step.
Common questions.
Does the injection hurt?
It's a small intramuscular injection. Most patients describe minimal discomfort — a brief sting at injection.
How quickly will I feel better?
Many patients notice improved energy within days of their first injection. Full improvement in B12-related fatigue and cognitive symptoms typically develops over 4–8 weeks of loading.
Can I get injections without a full Meliora consultation?
B12 injections are offered to established patients as part of their care plan. New patients begin with a consultation and labs to confirm the level and underlying cause of deficiency.
Questions? Send us a message.
We respond within one business day.
B12 deficiency is fixable — once you know it's there.
Book a consultation. We'll measure your level properly and determine whether injections are the right delivery for you.