Dosage: Determined by the prescribing healthcare provider on an individual basis based on the indication, severity of deficiency, and patient health profile. Do not adjust your dose without medical guidance.

Active ingredient: Methylcobalamin (Vitamin B12)

Form: Injectable solution

Routes of administration: IM, SubQ, or IV as directed

Prescription: Required

Routes of administration: Intramuscular (IM), Subcutaneous (SubQ), or Intravenous (IV), as directed by your provider. Injectable administration bypasses absorption limitations in the gut — particularly important for patients with pernicious anemia, gastric surgery, or malabsorption conditions where oral B12 cannot be reliably absorbed.

Deficiency in otherwise healthy individuals is uncommon, but certain populations are at significantly elevated risk:

The elderly: Reduced intrinsic factor production

Strict vegans / vegetarians: No dietary animal-source B12

Malabsorption conditions: Crohn's, celiac, gastric bypass

Pernicious anemia patients: Autoimmune loss of intrinsic factor

Long-term metformin users: Drug-induced B12 depletion

If left untreated, B12 deficiency can cause megaloblastic anemia, gastrointestinal disturbances, and — most seriously — irreversible peripheral nerve damage. Early treatment with injectable methylcobalamin can halt and, in many cases, partially reverse neurological damage.

Vitamin B12 is available in several forms, including cyanocobalamin, hydroxocobalamin, and methylcobalamin. Methylcobalamin is the biologically active coenzyme form — it can be used directly by the body without requiring conversion in the liver, unlike cyanocobalamin which must be converted before use.

Methylcobalamin is the only form of B12 that can cross the blood-brain barrier and enter the nervous system directly, making it the preferred form for neurological indications including peripheral neuropathy, nerve repair, and cognitive support.

Before beginning injectable B12 therapy, inform your healthcare provider of all current medications, known allergies — particularly to cobalt or cobalamin compounds — and any existing medical conditions, including Leber's hereditary optic neuropathy (LHON), in which vitamin B12 may accelerate optic nerve atrophy.

Methylcobalamin is generally very well tolerated. Mild and transient side effects may include injection site discomfort, mild itching, or transient diarrhea. Serious hypersensitivity reactions are rare but possible. If you experience rash, difficulty breathing, or swelling, discontinue use and seek medical attention immediately.

Patients with polycythemia vera, hypokalemia, or those undergoing treatment for megaloblastic anemia should be monitored closely during therapy, as rapid red blood cell recovery can shift serum potassium levels.

Store at controlled room temperature, away from direct light. Methylcobalamin is light-sensitive — keep vials protected from exposure to light at all times. Do not refrigerate or freeze unless specifically directed by your compounding pharmacy.

Inspect the vial before each use — the solution should be a clear, deep red. Do not administer if the solution appears cloudy, discolored, or contains visible particles. Keep out of reach of children. Dispose of used needles and unused medication in accordance with your pharmacy's or local authority's guidelines for pharmaceutical and sharps waste.