Methylcobalamin (B12)
Methylcobalamin is the bioactive coenzyme form of vitamin B12, a cofactor in methionine synthase (methylation), red blood cell formation, and neurological function.
Medically reviewed by Dr. Jonathan Snipes, MD. Last reviewed May 6, 2026.
What It Is
An injectable form of vitamin B12 as methylcobalamin, the pre-activated coenzyme the body uses directly without converting from cyanocobalamin. Self-administered intramuscular or subcutaneous.
How It Works
Methylcobalamin donates methyl groups in the methionine and folate cycles, supporting homocysteine metabolism, red blood cell production, and nerve myelination. Injection bypasses gut absorption, useful for patients with low B12 despite oral supplements.
Who It's For
Patients with low B12, fatigue, or malabsorption (including those on GLP-1 therapy), and anyone wanting the active methyl form rather than cyanocobalamin.
Who Should Avoid It
Known cobalt or cobalamin allergy. Use caution with Leber's hereditary optic neuropathy. Generally very well tolerated.
Protocol & Pricing
OBP Pharmacy Price
From $30/10ml
You pay pharmacy price. No markup.
Starting Dose
1mg (0.2mL) once weekly
Form
Injectable vial (10mL or 30mL, 5mg/mL methylcobalamin)
Dosing Protocol
1mg (0.2mL at 5mg/mL) intramuscular or subcutaneous once weekly, or per provider. Two vial sizes: 10mL ($30) and 30mL ($65).
Beyond Use Date
90 Days from compounding (USP <797>)
Optimal Balance Pharmacy assigns this date and prints it on your vial label. Always follow the label. Once a multi-dose vial is punctured, the in-use date on the label is shorter than the compounding date shown here.
Stacking Guide
Stacks Well With
Related Peptides
Lipo-B (Cyanocobalamin/MIC)
A lipotropic injection combining cyanocobalamin (B12) with methionine, inositol, and choline for fat metabolism.
From $30/10mlLipo-C (Cyanocobalamin/MIC/L-Carnitine)
Enhanced lipotropic injection adding L-carnitine to cyanocobalamin and MIC for improved energy and fat transport.
From $35/10mlVitamin B-Complex
Injectable B-complex (B1, B2, B3, B6) for energy metabolism and nervous system support.
$40/30mlHow to get Methylcobalamin (B12) prescribed online
Methylcobalamin (B12) is available by prescription through a licensed telehealth visit and dispensed for human use by a named 503A pharmacy. That is what separates it from research-use-only vials sold without a prescription. There is no subscription and no membership, just a one-time visit fee.
- 1
Complete a $39 medical visit. Answer a short intake about your health history and your goals for Methylcobalamin (B12). The $39 fee is the only charge RxPepsDirect collects, paid once, not a recurring subscription.
- 2
A licensed provider reviews it. A US-licensed nurse practitioner or physician reviews your intake and, if Methylcobalamin (B12) is appropriate for you, writes a patient-specific prescription. The starting dose is typically 1mg (0.2mL) once weekly.
- 3
The pharmacy compounds and ships it. Optimal Balance Pharmacy, a 503A pharmacy in Texas, compounds Methylcobalamin (B12) and ships it pre-reconstituted by FedEx overnight in a reusable cooled case. Your fill is Injectable vial (10mL or 30mL, 5mg/mL methylcobalamin), and you pay the pharmacy From $30/10ml at wholesale, with no clinic markup, plus a $15 flat FedEx overnight shipping fee charged by the pharmacy.
RxPepsDirect prescribes Methylcobalamin (B12) in the 29 jurisdictions its medical team is licensed in. Start a $39 visit or browse the full Vitamins & Injectables range. Comparing services first? See how RxPepsDirect stacks up against seven other providers in our best telehealth for compounded peptides comparison.
Common questions about Methylcobalamin (B12)
- What is Methylcobalamin (B12)?
- An injectable form of vitamin B12 as methylcobalamin, the pre-activated coenzyme the body uses directly without converting from cyanocobalamin. Self-administered intramuscular or subcutaneous.
- How does Methylcobalamin (B12) work?
- Methylcobalamin donates methyl groups in the methionine and folate cycles, supporting homocysteine metabolism, red blood cell production, and nerve myelination. Injection bypasses gut absorption, useful for patients with low B12 despite oral supplements.
- Who is Methylcobalamin (B12) for?
- Patients with low B12, fatigue, or malabsorption (including those on GLP-1 therapy), and anyone wanting the active methyl form rather than cyanocobalamin.
- How much does Methylcobalamin (B12) cost?
- Methylcobalamin (B12) costs From $30/10ml from Optimal Balance Pharmacy at wholesale, with a flat $39 medical visit fee from RxPepsDirect. The form is Injectable vial (10mL or 30mL, 5mg/mL methylcobalamin).
- What is the Beyond Use Date for Methylcobalamin (B12)?
- Optimal Balance Pharmacy assigns the Beyond Use Date for Methylcobalamin (B12) and prints it on the vial label. The listed figure is 90 Days from compounding (USP <797>). Always follow the date on your own label, and note that once a multi-dose vial is punctured, the in-use date on the label is shorter than the compounding BUD.