Methylcobalamin is one of the naturally occurring, bioactive coenzyme forms of vitamin B12. It plays crucial roles in:

DNA synthesis

Red blood cell formation

Neurological function

Myelin sheath formation and maintenance

Route of administration: Intramuscular (IM) or subcutaneous (SC)

Form: Injectable solution (usually 500 mcg/ml to 2500 mcg/ml)

Available as: Single or multi-dose vials, pre-filled syringes

Prescription required: Yes (in most countries)

Vitamin B12 deficiency

Peripheral neuropathy (especially diabetic neuropathy)

Megaloblastic anemia

Amyotrophic lateral sclerosis (ALS) (investigational)

Chronic fatigue syndrome

Alzheimer's disease (supportive use, under research)

Bell’s palsy, trigeminal neuralgia

Sciatica, neuralgia, and neuritis

Methylcobalamin serves as a coenzyme in the methionine synthase pathway, which:

Converts homocysteine to methionine (important for methylation processes)

Aids in synthesis of SAMe (S-adenosyl methionine), crucial for neurotransmitter synthesis and mood regulation

Supports myelin sheath maintenance, essential for nerve signal conduction

Dosage varies depending on the condition:

Typical adult dose:

For deficiency: 1000 mcg IM daily for 1 week, then weekly for 1 month, then monthly as maintenance

For neuropathy: 500 mcg to 1500 mcg IM 2–3 times/week

In Japan, high-dose therapy (up to 25,000 mcg/day) is used in some neurological conditions (investigational)

Note: Always follow physician’s recommendations.

Generally well-tolerated. Possible side effects include:

Mild pain/redness at injection site

Headache

Dizziness

Nausea

Rare: allergic reaction, rash, itching, anaphylaxis

Known allergy to cobalamin or cobalt

Leber’s disease (hereditary optic nerve atrophy): can cause optic nerve damage

Caution in patients with:

Polycythemia vera

Renal dysfunction

Hypokalemia (vitamin B12 Therapy can unmask this)

Storage

Store at room temperature (15–30°C), away from moisture and heat:

Keep out of reach of children

Important Notes

Use lowest effective dose for the shortest possible duration

Not for use as a first-line analgesic in general pain or fever

Always take under medical advice