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Methylcobalamin (Active B12) (Injectable)
Supplements

Methylcobalamin (Active B12) (Injectable)

Active B12 for energy & cognition

All-in monthly price

$229

No membership fee · this is the full price · free shipping · avg 4-week supply

Medication, provider care, labs & dose adjustments — all in one price.
~28-day supply. Your provider sets your exact dose, so yours may vary — your refill arrives as you finish the last one.
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This treatment requires licensed provider review and approval. Treatment is not guaranteed. If prescribed, medication is fulfilled by a licensed U.S. pharmacy where permitted by law. Compounded medications are not FDA-approved or FDA-cleared.

Dr. Gene
Physician Reviewed

Reviewed by Dr. Gene, MD · Board-certified Family Medicine

Every Pepti prescription is reviewed by a licensed U.S. physician before it's dispensed — and only provided if clinically appropriate.

About

Methylcobalamin (Active B12) (Injectable)

Methylcobalamin is the most active and bioavailable form of vitamin B12 — far more effective than oral B12 supplements. Supports energy, cognitive function, and nerve health. Weekly self-injection.

Benefits
Most bioavailable form of B12
Energy & cognitive support
Better than oral B12
Weekly injection
Supply per fill
28-day

About a 4-week supply supply at the standard prescribed dose — your physician confirms exact dosing.

Physician review
24 hrs

A licensed US physician reviews your intake and prescribes when appropriate.

FDA-registered pharmacy
503A

Compounded fresh at a US pharmacy and shipped cold-chain to your door.

Shipping, always
Free

Every order ships free — medication, physician care and refills, one all-in price.

Formulation
Injectable vial5 mL · 2 mg/mL
Methylcobalamin (B12)10 mg

Amounts shown are per unit. Compounded fresh at a US FDA-registered pharmacy.

Quality

Every batch independently tested

Every medication batch dispensed through Pepti is independently tested by a qualified third-party laboratory for applicable quality and safety standards before the pharmacy releases it. Batches are tested to the same standard used by 503B outsourcing facilities.

USP <71>
Sterility

Confirms the finished preparation is free of viable microorganisms.

USP <85>
Bacterial endotoxins

Screens for endotoxins that can cause fever or inflammatory reactions.

Assay
Potency

Verifies the labeled concentration of the active peptide is what is in the vial.

HPLC
Purity

Checks the active peptide against impurities and degradation products.

Mass spectrometry
Identity

Confirms the peptide in the vial is the correct molecule.

USP <791>
pH

Confirms the solution sits within the range specified for injection.

USP <788>
Particulate matter

Checks the finished vial for visible and sub-visible particles.

USP <1207>
Container closure integrity

Confirms the vial seal holds so sterility is maintained through the beyond-use date.

Compounded by licensed U.S. pharmacies. Prescribed by licensed medical providers. Shipped directly to patients.Documentation available upon request →View lab results by lot →
Your protocol

How Methylcobalamin is prescribed.

Who it's for
  • Adults who feel tired all the time and want to rule out low B12
  • People on metformin, acid reducers or a plant-based diet, which all lower B12
  • Anyone with tingling or numbness their physician has linked to B12
  • Patients who want the active form rather than the cheaper cyanocobalamin

Your physician decides whether Methylcobalamin is appropriate for you after reviewing your intake and labs.

Directions & duration

Inject 1.25 mL (125 units) intramuscularly once weekly.

Cycle. One injection into the muscle once a week. Ongoing monthly treatment.
Directions shown are the pharmacy's standard for this preparation. Your prescription label is the final word.
What's included
  • Licensed physician review of your intake, history, and labs
  • Medication compounded to your prescription by a PCAB-accredited, FDA-registered pharmacy
  • Every batch independently tested before release
  • Sterile syringes and alcohol prep pads for injectables
  • Tracked delivery to your door, refills on schedule
  • Message your physician anytime; dose changes without an appointment
Storage & handling
  • Store refrigerated (36–46°F / 2–8°C) at all times, including before first use.
  • One vial is your monthly supply. A fresh vial ships every 28 days on your refill schedule, so you're always well inside the beyond-use date on your label.
  • Protect from light. Wipe the stopper with an alcohol pad before every draw.
  • Dispose of syringes in the sharps container per the included instructions.
What to expect

A typical course of Methylcobalamin.

TimeframeWhat patients commonly report
Weeks 1–2More energy is the first thing patients who were low report, often within the first two weeks.
Weeks 3–8Nerve and mood changes, where reported, build more slowly.
OngoingLong-term treatment. Refills ship every 28 days, and your physician adjusts the dose over time as your goals evolve.
Individual results vary. Compounded medications are not FDA-approved; a licensed physician determines whether treatment is appropriate and monitors your progress.
The full reference

Everything published
about Methylcobalamin (Active B12).

How it is described to work, pathway by pathway. What the research shows and what it does not. Where it stands with the FDA, dated and sourced.

Read the reference
12
References

peer-reviewed, each verified on PubMed

14
Sections

mechanism, evidence, dosing, safety, FAQ

Sep 24
FDA status verified

2026 · checked against fda.gov, not memory

The science

How Methylcobalamin works, and what the research shows.

How it works

Methylcobalamin is the active form of vitamin B12 your body uses directly, needed for energy production, red blood cells and the coating on nerves.

As a weekly injection it bypasses the gut entirely.

Clinical evidence
  • B12 injection is standard care for deficiency.

  • In people with normal levels the energy effect is modest and is reported mostly by those who were running low.

Full references with PubMed links are listed further down the page.

References

  1. Stabler SP. Clinical practice. Vitamin B12 deficiency · N Engl J Med (2013) · PMID 23301732
  2. Devalia V, Hamilton MS, Molloy AM. Guidelines for the diagnosis and treatment of cobalamin and folate disorders · Br J Haematol (2014) · PMID 24942828
  3. Wolffenbuttel BHR, Wouters HJCM, Heiner-Fokkema MR, van der Klauw MM. The Many Faces of Cobalamin (Vitamin B12) Deficiency · Mayo Clin Proc Innov Qual Outcomes (2019) · PMID 31193945
  4. Kuzminski AM, Del Giacco EJ, Allen RH, Stabler SP, Lindenbaum J. Effective treatment of cobalamin deficiency with oral cobalamin · Blood (1998) · PMID 9694707
  5. Obeid R, Fedosov SN, Nexo E. Cobalamin coenzyme forms are not likely to be superior to cyano- and hydroxyl-cobalamin in prevention or treatment of cobalamin deficiency · Mol Nutr Food Res (2015) · PMID 25820384
  6. Aroda VR, Edelstein SL, Goldberg RB, et al.. Long-term Metformin Use and Vitamin B12 Deficiency in the Diabetes Prevention Program Outcomes Study · J Clin Endocrinol Metab (2016) · PMID 26900641
  7. Pawlak R, Parrott SJ, Raj S, Cullum-Dugan D, Lucus D. How prevalent is vitamin B12 deficiency among vegetarians? · Nutr Rev (2013) · PMID 23356638
  8. Pawlak R, Lester SE, Babatunde T. The prevalence of cobalamin deficiency among vegetarians assessed by serum vitamin B12: a review of literature · Eur J Clin Nutr (2014) · PMID 24667752
  9. Ellis FR, Nasser S. A pilot study of vitamin B12 in the treatment of tiredness · Br J Nutr (1973) · PMID 4583554
  10. Mandra EV, Parfenov VA, Stupin VA, Silina EV. Vitamin B Supplementation for Diabetic Peripheral Neuropathy: A Review and Meta-Analysis · J Clin Med (2026) · PMID 42452619
  11. Vaucher P, Druais PL, Waldvogel S, Favrat B. Effect of iron supplementation on fatigue in nonanemic menstruating women with low ferritin: a randomized controlled trial · CMAJ (2012) · PMID 22777991
  12. Stuber MJ, Moutzouri E, Feller M, et al.. Effect of Thyroid Hormone Therapy on Fatigability in Older Adults With Subclinical Hypothyroidism: A Nested Study Within a Randomized Placebo-Controlled Trial · The Journals of Gerontology. Series A, Biological Sciences and Medical Sciences (2020) · PMID 32577745

Citations are provided for educational purposes. They do not constitute medical advice. Always discuss any peptide protocol with your prescribing physician.

Important safety information

+

Possible side effects

• Mild redness or swelling at injection site
• Temporary fatigue or headache
• Mild nausea (uncommon)

Do not use if you have

• Active cancer or history of cancer (unless approved by oncologist)
• Pregnancy or breastfeeding
• Severe kidney or liver disease
• Known allergy to the peptide or excipients

If you experience severe side effects, call 911 or go to your nearest emergency room.

How supplied

vial — Methylcobalamin B12 10mg/5mL 2mg/mL (5mL)

Common questions

Frequently asked
about Methylcobalamin (Active B12) (Injectable).

Methylcobalamin is the most active and bioavailable form of vitamin B12 — far more effective than oral B12 supplements. Supports energy, cognitive function, and nerve health. Weekly self-injection. Methylcobalamin (Active B12) is prescription-only at Pepti: a licensed physician reviews your assessment and, if appropriate, prescribes it to be compounded by a state-licensed, FDA-registered pharmacy.

33 more questions about Pepti, answered.

One vial is your monthly supply at the dose your physician prescribes. A fresh vial ships about every 28 days, and the date moves if your physician changes your dose. Store it as the pharmacy label directs, refrigerated.

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Pharmacy network accreditation

PCAB-accredited pharmacies on every order.

Every fulfillment runs through a PCAB-accredited pharmacy.

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PCAB — Pharmacy Compounding Accreditation Board · Accredited
  • Rigorous third-party quality & safety inspections
  • Cleanliness and sterile processes
  • Proper ingredient sourcing
  • Accurate dosing and formulation
  • Staff training and procedures
  • Accredited by NABP & ACHC