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Methylcobalamin (B12)

Methylcobalamin is the bioactive coenzyme form of vitamin B12, a cofactor in methionine synthase (methylation), red blood cell formation, and neurological function.

Dr. Jonathan Snipes, MDMedically reviewed by Dr. Jonathan Snipes, MD. Last reviewed May 6, 2026.
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Methylcobalamin B12 injectable vial compounded by a licensed U.S. 503A compounding pharmacy for Rx Peps Direct

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Active B12 FormEnergy SupportMethylationSelf-Inject

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.

Ready to add Methylcobalamin (B12)?

A licensed provider reviews every order.

Protocol & Pricing

Pharmacy Price

$30/10ml

You pay pharmacy price. No markup.

Starting Dose

1mg (0.2mL) once weekly

Form

Injectable vial (10mL, 5mg/mL methylcobalamin)

Dosing Protocol

1mg (0.2mL at 5mg/mL) intramuscular or subcutaneous once weekly, or per provider. Single 10mL vial ($30).

Beyond Use Date

60 Days from compounding (USP <797>)

A licensed U.S. 503A compounding pharmacy assigns this date and prints it on your vial label. Always follow the label.

Ready to add Methylcobalamin (B12)?

A licensed provider reviews every order.

Stacking Guide

Stacks Well With

Lipo-B (Cyanocobalamin/MIC)Lipo-C (Cyanocobalamin/MIC/L-Carnitine)Vitamin B-Complex

Ready to add Methylcobalamin (B12)?

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Related Peptides

Lipo-B (Cyanocobalamin/MIC)

A lipotropic injection combining cyanocobalamin (B12) with methionine, inositol, and choline for fat metabolism.

From $30/10ml

Lipo-C (Cyanocobalamin/MIC/L-Carnitine)

Enhanced lipotropic injection adding L-carnitine to cyanocobalamin and MIC for improved energy and fat transport.

From $35/10ml

Vitamin B-Complex

Injectable B-complex (B1, B2, B3, B6) for energy metabolism and nervous system support.

$40/30ml

Independently tested

Methylcobalamin (B12) certificate of analysis

All 2 Methylcobalamin (B12) samples tested for sterility and endotoxin passed both. Latest sample received by the lab Oct 12, 2026.

Every Methylcobalamin (B12) batch dispensed by a licensed U.S. 503A compounding pharmacy is independently tested by Eagle Analytical Services (FDA-registered, A2LA ISO 17025 accredited). Sterility testing checks that nothing grows in the sample; the USP <85> endotoxin test checks for bacterial toxins that can cause fever. Below is the lab's own report for each of the 2 most recent lots.

Lot LG342011208, received Oct 12, 2026

Sterility
PassScanRDI Sterility Test. Started Oct 12, 2026, completed Oct 14, 2026. Method suitability ETX-250924-0204
Bacterial endotoxin
PassUSP <85>. Measured <2 EU/mL, limit 700 EU/mL. Started Oct 13, 2026, completed Oct 13, 2026
Sample, as printed
METHYLCOBALAMIN 5 MG/ML (10 ML) Injection
Lot #
LG342011208
Storage
Refrigerated
Received by lab
Oct 12, 2026
Laboratory
Eagle Analytical Services Inc., Houston, TX
Submission #
ETX-261010-0051
Signed
Alison Eng, Quality Control Manager
Scan of Eagle Analytical report ETX-261010-0051 for lot LG342011208. Opens the original PDF.
Eagle Analytical report ETX-261010-0051. Open the original PDF (opens in a new tab)

Eagle Analytical Services is an independent FDA-registered laboratory, A2LA accredited to ISO 17025, based in Houston, Texas. They have no commercial relationship with Rx Peps Direct. Rx Peps Direct prescribes; the pharmacy compounds and dispenses; Eagle tests every batch. Three separate companies. Results apply only to the tested sample as received. Browse our full quality program on the quality page.

Ready to add Methylcobalamin (B12)?

A licensed provider reviews every order.

How to get Methylcobalamin (B12) prescribed online

Methylcobalamin (B12) is available by prescription after an online medical review and dispensed for human use by a licensed 503A pharmacy. That is what separates it from research-use-only vials sold without a prescription. There is no membership, just a medical review fee per order, and automatic refills are optional.

  1. 1

    Complete a $39 medical review. Answer a short intake about your health history and your goals for Methylcobalamin (B12). The $39 fee is the only charge Rx Peps Direct collects, paid once, not a recurring subscription.

  2. 2

    A licensed provider reviews it. A US-licensed clinician 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. 3

    The pharmacy compounds and ships it. A licensed 503A compounding 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, 5mg/mL methylcobalamin), and you pay the pharmacy $30/10ml at wholesale, with no clinic markup, plus a $15 flat FedEx overnight shipping fee charged by the pharmacy.

Rx Peps Direct prescribes Methylcobalamin (B12) in the 28 states plus Washington, DC where its medical team is licensed. Start your $39 medical review or browse the full Vitamins & Injectables range. Comparing services first? See how Rx Peps Direct stacks up against seven other providers in our best telehealth for compounded peptides comparison.

Ready to add Methylcobalamin (B12)?

A licensed provider reviews every order.

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 $30/10ml from a licensed U.S. 503A compounding pharmacy at wholesale, with a flat $39 medical review from Rx Peps Direct. The form is Injectable vial (10mL, 5mg/mL methylcobalamin).
What is the Beyond Use Date for Methylcobalamin (B12)?
A licensed U.S. 503A compounding pharmacy assigns the Beyond Use Date for Methylcobalamin (B12) and prints it on the vial label. The listed figure is 60 Days from compounding (USP <797>). Always follow the date on your own label.

Ready to add Methylcobalamin (B12)?

A licensed provider reviews every order.