Interactions on record — worth a quick check against your medications. Check your meds →
Dietary supplement

Methyl B-12 5,000 mcg Ingredients & Drug Interactions

by NOW

Methyl B-12 5,000 mcg label
See full label image
Capsule Category: Vitamin
Most serious interaction: Minor
Clinical methodology reviewed by · Updated Sep 9, 2026 · Label data from the NIH DSLD
What is this page for?

First and foremost: checking Methyl B-12 5,000 mcg against your medications. The heart of this page is the interaction checker and the full interaction report — how this product’s ingredients may interact with prescription and over-the-counter medicines you may be taking.

Around that, we add a pharmacist’s high-level view of the product as a whole — what’s inside, the evidence for its stated use, how transparent the label is, and what safety data exists — so you can see the full picture in one place. It’s educational information from our licensed clinical databases and the clinical staff at HelloPharmacist — not medical advice — and we don’t sell or endorse products. Our editorial policy

The interaction bottom line Most serious interaction: Minor

Methyl B-12 5,000 mcg is a dietary supplement by NOW with 1 active ingredient. Its ingredients are commonly taken for treating or preventing b12 deficiency, pernicious anemia, low energy and fatigue.Based on those ingredients, 20 medications have a known interaction with it, the most serious rated minor. The ingredients most likely to interact are Vitamin B12. Use the checker below to test your specific medication, or read the full HelloPharmacist Interaction Report.

Jump to a section

Check Your Meds Against Methyl B-12 5,000 mcg by NOW

Ask about any prescription or over-the-counter medication and we check it for interactions with Methyl B-12 5,000 mcg by NOW — and tell you which ingredient is responsible.

Pharmacist-reviewed data Checks every ingredient Answer in seconds
Prefer a human? Send your question to our licensed pharmacists — free, answered by email within 24 hours.

HelloPharmacist Scorecard of Methyl B-12 5,000 mcg by NOW

Our pharmacy team’s full take, with four database checks built into the cards below — a summary of what is known, not a grade of the product itself.

From our pharmacy team — supplement deep dive

Generated from HelloPharmacist’s pharmacist-curated databases and editorial rules · Last generated Aug 20, 2026

What’s inside

Full disclosure
Ingredient Transparency · database check
Full

Every active ingredient lists its own amount on the label.

Why this rating?
  • The label discloses an exact amount for 1 of its 1 active ingredient.
  • No proprietary blends here — you can verify the dose of every single component.

This supplement contains one active ingredient: vitamin B12 (in the methyl form, also called methylcobalamin) at 5,000 micrograms per capsule. B12 is a water-soluble vitamin your body uses for nerve function, red blood cell formation, and DNA synthesis.

The capsule also contains inactive ingredients — rice flour, microcrystalline cellulose, hypromellose, stearic acid, and silicon dioxide — which are binders and fillers.

Does it work?

Strong evidence
Evidence for Intended Use · database check
By FDA rules, dietary supplements can’t claim to treat, cure, or prevent disease — so labels speak in careful marketing language. We discern each product’s intended use from its name, label claims, and label statements, then grade the clinical evidence for that use. How these ratings are computed
Strong

Clinical evidence supports at least one of this product's ingredients for its stated purpose.

Why this rating?
  • The label markets this product for: nervous system health and energy production.
  • We looked for evidence on: Vitamin B12 deficiency, Fatigue, Peripheral neuropathy, Chemotherapy-induced peripheral neuropathy, Diabetic neuropathy, Hyperhomocysteinemia — and 3 related terms.
  • The strongest evidence on file: Vitamin B12 is rated "Effective" for Vitamin B12 deficiency (Natural Medicines).
  • Also on file: Vitamin B12 is rated "Possibly Effective" for Hyperhomocysteinemia.
  • Also on file: Vitamin B12 is rated "Insufficient Reliable Evidence To Rate" for Chemotherapy-induced peripheral neuropathy, Diabetic neuropathy, Fatigue, Peripheral neuropathy.

Vitamin B12 is effective for treating B12 deficiency and Imerslund-Grasbeck disease (a rare genetic disorder affecting B12 absorption). It's also likely effective for cyanide poisoning.

For canker sores and nerve pain after shingles (postherpetic neuralgia), the evidence is less robust — B12 is possibly effective, meaning the research is suggestive but not yet conclusive.

The evidence, ingredient by ingredient Vitamin B12

How safe is it?

Well-documented data
Safety Information · database check
Well characterized

Adverse-effect, pregnancy, and general safety data are on file for most of these ingredients.

Why this rating?
  • We hold adverse-effect (side-effect) data for 1 of the 1 matched ingredient.
  • Pregnancy & breastfeeding safety ratings cover 1 of 1.
  • General safety write-ups exist for 1 of 1.
  • Remember: this measures how much safety information exists. Thin data is not the same as being safe.

Vitamin B12 is generally very well tolerated orally. Because it's water-soluble, your body excretes excess amounts in urine, so there's no established upper limit.

Allergic reactions like rash or hives are rare but possible, especially in people with a cobalt allergy (since cobalt is part of the B12 molecule). B12 is considered safe during pregnancy and breastfeeding at recommended amounts, and it's actually needed during both — follow your provider's guidance on dosing for your situation.

Side effects, ingredient by ingredient Vitamin B12

Meds to double-check

Minor interactions only
Known Interaction Concern · database check
Minor only

Only Minor-severity interactions are documented for these ingredients.

Why this rating?
  • 1 of the 1 matched ingredient can interact with medications — Vitamin B12.
  • The most serious interaction on file is rated Minor.
  • For scale: 20 individual medications appear in the full list. A big number alone doesn't make a product dangerous — what matters is whether YOUR medication is on it, so run yours through the interaction checker on this page.

If you take metformin for diabetes, flag this one with your pharmacist — the supplement may help offset the B12 loss that metformin can cause over time, but your doctor should know you're taking it so they can monitor your levels if needed. No other interactions are documented for the ingredient we could check.

Check your own medication Run your meds through the checker above

The bottom line

Scorecard at a glanceFully disclosed formula with clinical evidence supporting its stated purpose. Only minor medication interactions are documented, and safety information is well characterized.

If you have B12 deficiency or take metformin, this supplement is worth a conversation with your doctor or pharmacist. It's very safe at this dose and unlikely to cause side effects in most people.

Run it through the medication checker on this page to confirm it won't interfere with anything you're taking, and then confirm the dose is right for you.

Educational only — not medical advice; always confirm with your pharmacist. Our editorial policy · How we use AI

Assessment coverage: 1 of 1 active ingredient matched to our full ingredient reviews (monographs). Based on the product label dated Mar 25, 2021.

This Scorecard evaluates available label information, ingredient evidence, and known medication-safety considerations. It does not independently verify product identity, purity, potency, contamination, or manufacturing quality. How these ratings are computed

At a glance

General information

Key facts about Methyl B-12 5,000 mcg, straight from the product label.

Brand NOW
Barcode (UPC) 733739005052
Net contents 90 Veg Capsule(s)
Market status On market
Date entered into DSLD Mar 25, 2021
DSLD ID 245891
Product type Vitamin
Supplement form Capsule
Dietary claims / uses Nutrient, All Other, Structure/Function
Intended target group(s) Vegan, Vegetarian, Adult (18 - 50 Years), Gluten Free, Dairy Free
From the label
Everything in this section is reproduced from the manufacturer’s own product label — it’s the label speaking, not HelloPharmacist. We show it so you can see exactly what the maker states; we don’t verify or endorse those statements.

Supplement Facts

The label details for Methyl B-12 5,000 mcg by NOW, sourced from the NIH Dietary Supplement Label Database.

Supplement Facts

Daily Value (DV) Target Group(s):
Adults and children 4 or more years of age
Minimum serving Sizes:
1 Veg Capsule(s)
Maximum serving Sizes:
1 Veg Capsule(s)
Servings per container
90
UPC/BARCODE
733739005052
IngredientAmount% DV
Vitamin B125 mg208333%

Other ingredients: Rice Flour, Microcrystalline Cellulose, Hypromellose, Stearic Acid, Silicon Dioxide

Tap any ingredient to jump to its full detail below.

Label statements
These statements are the manufacturer’s wording, reproduced from the product label — the label is saying it, not HelloPharmacist. We don’t verify or endorse them.
Suggested/Recommended/Usage/Directions

Suggested Usage: Take 1 capsule daily.

Formula

Vitamin B-12 is necessary for the production of energy from fats and proteins and is well known for its critical role in DNA synthesis, as well as in homocysteine metabolism. Methylcobalamin is the co-enzyme form of vitamin B-12 that has been found to be especially critical in the maintenance of a healthy nervous system. Dietary sources are almost exclusively of animal origin (meat and dairy) and supplementation with B-12 may be especially important for strict vegetarians.

Methylcobalamin

FDA Disclaimer Statement

These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure or prevent any disease.

Precautions

Caution: For adults only.

Consult a physician if pregnant/nursing, taking medication or have a medical condition.

Keep out of reach of children.

Not manufactured with yeast, wheat, gluten, soy, corn, milk, egg, fish, shellfish or tree nut ingredients. Produced in a GMP facility that processes other ingredients containing these allergens.

Formulation

Natural color variation may occur in this product.

Nervous System Health Essential for Energy Production Hypoallergenic

Non-GMO

Vegetarian/Vegan

Not manufactured with yeast, wheat, gluten, soy, corn, milk, egg, fish, shellfish or tree nut ingredients.

NOW Methyl B-12 is vegetarian/vegan (non-animal derived).

FDA Statement of Identity

A Dietary Supplement

General Statements

Vitamins Family owned since 1968.

Storage

Store in a cool, dry place after opening.

Seals/Symbols

GMP Quality Assured

Is this label outdated? Report a formula or label change and our pharmacy team will review it.

See for yourself

Methyl B-12 5,000 mcg by NOW label

The label scan from the NIH Dietary Supplement Label Database. Tap to enlarge.

Methyl B-12 5,000 mcg label

Label images are published by the NIH Dietary Supplement Label Database for the version of this product on file. Always read your actual product label.

View the full label (PDF)
What’s inside

The Ingredients in Methyl B-12 5,000 mcg by NOW

This is the 1 active ingredient this product is made of. Select it to open its full monograph.

Serving size1 Veg Capsule(s) Dosage formCapsule Servings per container90 Amounts shown are per serving.

Vitamin B12

Interacts with
20 drugs
5 mg per serving Form: Methylcobalamin

Vitamin B12 (cobalamin) is an essential nutrient your body needs to make red blood cells, keep nerves healthy, and support DNA. Supplements are very h...

Vitamin B12 monograph & interactions

Other (inactive) ingredients: Rice Flour, Microcrystalline Cellulose, Hypromellose, Stearic Acid, Silicon Dioxide. These complete the product’s ingredient list but are not active constituents.

Interaction report

Methyl B-12 5,000 mcg by NOW Drug Interactions

Want to check YOUR meds against Methyl B-12 5,000 mcg?

Ask about interactions with your drugs in plain English — “Can I take it with lisinopril?” — and we find you the answer in seconds, ingredient by ingredient.

 Go to the checker
20Drugs
20 Minor

Ingredients driving the most interactions

Vitamin B12 20

Individual Drug Interactions

The ingredients in Methyl B-12 5,000 mcg interact with 20 drugs. Click any drug to see the details.

1 of the 1 ingredient in Methyl B-12 5,000 mcg interact with drugs. Each result below shows which ingredient is responsible. Vitamin B12

Each ingredient & the kinds of drugs it affects

For each ingredient in Methyl B-12 5,000 mcg with known interactions, here are the types of medications it can affect. Open any type for the detail — or search your exact drug in the checker above.

Vitamin B121 drug type · 20 drugs

Metformin (Glucophage)

Metformin, a common medication used to manage type 2 diabetes, has been associated with lower vitamin B12 levels in some individuals. Prolonged use of metformin can interfere with the absorption of B12 in the digestive system, potentially leading to a deficiency in this essential vitamin.

Likelihood Possible Evidence A
Vitamin B12 full monograph & interactions
The maker

Brand information

Manufacturer and brand details for Methyl B-12 5,000 mcg, from the product label.

NOW

See all NOW products
Name
NOW Foods
Street Address
395 S. Glen Ellyn Rd.
City
Bloomingdale
State
IL
ZipCode
60108
Web Address
nowfoods.com
Pharmacist Counseling Corner

Methyl B-12 5,000 mcg by NOW: Common Questions

Does Methyl B-12 5,000 mcg by NOW interact with any medications?
Yes. Based on its ingredients, Methyl B-12 5,000 mcg has a known interaction with 20 medications. Use the checker to see how it interacts with a specific drug.
How can one product interact with so many drugs?
Methyl B-12 5,000 mcg contains a single active ingredient, and that one ingredient can interact with many different medications on its own. We check it against each medication and show the mechanism responsible.
Where does this information come from?
The product label data comes from the NIH Dietary Supplement Label Database (DSLD); the interaction data is built on the Natural Medicines database and reviewed by HelloPharmacist pharmacists.
Will this help my vitamin B12 deficiency?
Yes — B12 is effective for treating B12 deficiency. If you've been diagnosed with low B12, this is a straightforward use. Make sure the 5,000 mcg dose matches what your doctor recommends for your situation.
I take metformin for diabetes. Is this supplement safe for me?
There's a Minor interaction: metformin can lower your B12 levels by interfering with absorption, which is actually one reason people on metformin sometimes need B12 supplementation. Talk with your doctor about whether adding B12 makes sense for you and what dose is appropriate.
Can I take this while pregnant or breastfeeding?
Yes. B12 is considered safe during pregnancy and breastfeeding at recommended amounts, and it's actually important during both. Follow your provider's advice on the right dose for you.
What are the side effects?
B12 taken by mouth is generally very well tolerated with few side effects. Allergic reactions like rash or itching are rare but possible, especially if you have a cobalt allergy. Serious side effects are very uncommon.
Will this help with nerve pain or canker sores?
Possibly. The evidence is suggestive but not yet conclusive for canker sores and nerve pain after shingles, so results vary. It's more clearly effective for B12 deficiency.
Is there anything else in the capsule besides B12?
The active ingredient is just B12. The capsule also contains inactive ingredients — rice flour, cellulose, and a few other binders and fillers to hold it together.

Written and reviewed by the HelloPharmacist editorial staff. Our editorial policy

Not sure if Methyl B-12 5,000 mcg is safe with your meds?

Our pharmacists answer your medication & supplement questions — free.

Ask a pharmacist

Label information is sourced from the NIH Dietary Supplement Label Database and reflects the product version on file; always read your actual product label. This page is for education only and is not a substitute for professional medical advice. Confirm with your pharmacist or doctor before combining supplements and medications.

Methyl B-12 5,000 mcg label
Go deeper

The Full Monographs Behind Methyl B-12 5,000 mcg’s Ingredients

Every ingredient we hold a full HelloPharmacist monograph for — uses, evidence, safety, and the complete interaction list.

Herb & supplement monograph

Vitamin B12

Interacts with 20 drugs

Vitamin B12 (cobalamin) is an essential nutrient your body needs to make red blood cells, keep nerves healthy, and support DNA. Supplements are very helpful for people who are deficient — su...

Read the full Vitamin B12 monograph →
Sources

Sources & How We Checked

Methyl B-12 5,000 mcg's label data comes from the NIH Dietary Supplement Label Database; the ingredient interaction data is from the Natural Medicines database, reviewed by our pharmacists.

Content is written and reviewed by licensed HelloPharmacist pharmacists. See our data sources and editorial standards for how this information is built and checked.

The 30 references behind this product’s interaction data

Every citation that drives the interaction findings for this product’s ingredients, from the evidence-graded Natural Medicines (TRC Healthcare) database. Open an ingredient to browse its citations — links open the study on PubMed or the publisher’s site.

Vitamin B12 30 references
  1. Food and Nutrition Board, Institute of Medicine. Dietary Reference Intakes for Thiamin, Riboflavin, Niacin, Vitamin B6, Folate, Vitamin B12, Pantothenic Acid, Biotin, and Choline (2000). Washington, DC: National Academy Press, 2000. Available at: http://b
  2. Hartman TJ, Woodson K, Stolzenberg-Solomon R, et al. Association of the B-vitamins pyridoxal 5'-phosphate (B6), B12, and folate with lung cancer risk in older men. Am J Epidemiol 2001;153:688-94.. DOI
  3. Jansen T, Romiti R, Kreuter A, Altmeyer P. Rosacea fulminans triggered by high-dose vitamins B6 and B12. J Eur Acad Dermatol Venereol 2001;15:484-5..
  4. Lange H, Suryapranata H, De Luca G, et al. Folate therapy and in-stent restenosis after coronary stenting. N Engl J Med 2004;350:2673-81. PubMed
  5. Collin, S. M., Metcalfe, C., Refsum, H., Lewis, S. J., Zuccolo, L., Smith, G. D., Chen, L., Harris, R., Davis, M., Marsden, G., Johnston, C., Lane, J. A., Ebbing, M., Bonaa, K. H., Nygard, O., Ueland, P. M., Grau, M. V., Baron, J. A., Donovan, J. L., Nea
  6. Geissbuhler, P., Mermillod, B., and Rapin, C. H. Elevated serum vitamin B12 levels associated with CRP as a predictive factor of mortality in palliative care cancer patients: a prospective study over five years. J.Pain Symptom.Manage. 2000;20(2):93-103. PubMed
  7. Salles, N., Herrmann, F., Sakbani, K., Rapin, C. H., and Sieber, C. High vitamin B12 level: a strong predictor of mortality in elderly inpatients. J Am Geriatr.Soc 2005;53(5):917-918.
  8. Looker, H. C., Fagot-Campagna, A., Gunter, E. W., Pfeiffer, C. M., Sievers, M. L., Bennett, P. H., Nelson, R. G., Hanson, R. L., and Knowler, W. C. Homocysteine and vitamin B(12) concentrations and mortality rates in type 2 diabetes. Diabetes Metab Res R
  9. Uhl, W., Nolting, A., Golor, G., Rost, K. L., and Kovar, A. Safety of hydroxocobalamin in healthy volunteers in a randomized, placebo-controlled study. Clin Toxicol (Phila) 2006;44 Suppl 1:17-28. PubMed
  10. Borron, S. W., Baud, F. J., Barriot, P., Imbert, M., and Bismuth, C. Prospective study of hydroxocobalamin for acute cyanide poisoning in smoke inhalation. Ann Emerg.Med 2007;49(6):794-801, 801. PubMed
  11. Borron, S. W., Baud, F. J., Megarbane, B., and Bismuth, C. Hydroxocobalamin for severe acute cyanide poisoning by ingestion or inhalation. Am J Emerg.Med 2007;25(5):551-558. PubMed
  12. Lewis, J. G. Gout, Steatorrhoea, and Megaloblastic Anaemia. Ann Rheum.Dis 1962;21(3):284-286. PubMed
  13. Tal, S., Shavit, Y., Stern, F., and Malnick, S. Association between vitamin B12 levels and mortality in hospitalized older adults. J Am Geriatr.Soc 2010;58(3):523-526. PubMed
  14. Baztan, J. J., Gavidia, J. J., Gomez-Pavon, J., Esteve, A., and Ruiperez, I. High vitamin B12 levels and in-hospital mortality. J Am Geriatr.Soc 2010;58(11):2237-2238. PubMed
  15. Omboni, E., Checchini, M., and Longoni, F. [Hypopotassemia and megaloblastic anemia. Presentation of a case]. Minerva Med 8-31-1987;78(16):1255-1257.
  16. Aalfs As, Scholvinck LH, Horvath B. Acneiform eruption in a 5-year old due to vitamin B12 supplementation. Eur J Dermatol 2013;23(5):726-7. PubMed
  17. Balta I, Ozuguz P. Vitamin B12-induced acneiform eruption. Cutan Ocul Toxicol 2014;33(2):94-5. PubMed
  18. Carman KB, Belgemen T, Yis U. Involuntary movements misdiagnosed as seizure during vitamin B12 treatment. Pediatr Emerg Care 2013;29(11):1223-4. PubMed
  19. Djuric V, Bogic M, Popadic AP, et al. Anaphylactic reaction to hydroxycobalamin with tolerance to cyanocobalamin. Ann Allergy Asthma Immunol 2012;108(3):207-8. PubMed
  20. Kartel O, Gulec M, Demirel F, et al. Vitamin B12 allergy and successful desensitization with cyanocobalamin: A case report. Allergol Immunopath (Madr) 2012;40(5):324-5.
  21. Patiroglu T, Unal E, Yildirim S. Infantile tremor syndrome associated with cobalamin therapy: A case report. Clin Neurol Neurosurg 2013;115(9):1903-5. PubMed
  22. Schulte S, Barkema LW, Kardaun SH. Long-lasting atypical acneiform eruption with prominent comedones induced by hydroxocobalamin (vitamin B12). J Dtsch Dermatol Ges 2014;12(6):502-3.
  23. Zanus C, Alberini E, Costa P, et al. Involuntary movements after correction of vitamin B12 deficiency: A video-case report. Epileptic Disord 2012;14(2):174-80. PubMed
  24. Fanidi A, Carreras-Torres R, Larose TL, et al. Is high vitamin B12 status a cause of lung cancer? Int J Cancer. 2019 Sep 15;145(6):1499-1503. PubMed
  25. Fujita Y, Mizukami T, Maya Y, et al. Vitamin B12 allergy manifesting as lymphomatoid contact dermatitis. Eur J Dermatol. 2020;30(3):304-305. PubMed
  26. Dépret F, Hoffmann C, Daoud L, et al. Association between hydroxocobalamin administration and acute kidney injury after smoke inhalation: a multicenter retrospective study. Crit Care. 2019;23(1):421. PubMed
  27. Khairan P, Sobue T, Eshak ES, et al. Association of dietary intakes of vitamin B12, vitamin B6, folate, and methionine with the risk of esophageal cancer: the Japan Public Health Center-based (JPHC) prospective study. BMC Cancer 2021;21(1):982. PubMed
  28. Evans J, Pandya A, Ding Y, Qunibi WY. Hydroxocobalamin-Induced Oxalate Nephropathy in a Patient With Smoke Inhalation. Kidney Int Rep 2021;6(8):2228-2231. PubMed
  29. Lacombe V, Chabrun F, Lacout C, et al. Persistent elevation of plasma vitamin B12 is strongly associated with solid cancer. Sci Rep 2021;11(1):13361. PubMed
  30. Pegalajar-García MD, Cebolla-Verdugo M, Prados-Carmona Á, Llamas-Segura C, Navarro-Triviño FJ. Systemic allergic dermatitis to cobalt present in cyanocobalamin supplementation. Contact Dermatitis 2023;89(3):203-205. PubMed

See these in context on the Vitamin B12 monograph →

Parts of this content are provided by the Therapeutic Research Center, LLC.

DISCLAIMER: Currently this does not check for drug-drug interactions. This is not an all-inclusive comprehensive list of potential interactions and is for informational purposes only. Not all interactions are known or well-reported in the scientific literature, and new interactions are continually being reported. Input is needed from a qualified healthcare provider including a pharmacist before starting any therapy. Application of clinical judgment is necessary.

© 2021 Therapeutic Research Center, LLC

Keep exploring
Supplement interaction checker › Check any supplement or product against your medications Drug–drug interactions › Check two or more of your medications against each other Browse medications A–Z › Every drug we've checked against herbs & supplements NDC & pricing lookup › Find a drug’s NDCs, packaging and costs Ask a pharmacist › Free, personal answer from our licensed team