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Dietary supplement

B-1 100 mg Thiamin Ingredients & Drug Interactions

by Carlson

B-1 100 mg Thiamin label
See full label image
Tablet Or Pill Category: Vitamin
Most serious interaction: Minor
Clinical methodology reviewed by · Updated Sep 16, 2026 · Label data from the NIH DSLD
What is this page for?

First and foremost: checking B-1 100 mg Thiamin 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

B-1 100 mg Thiamin is a dietary supplement by Carlson with 1 active ingredient. Its ingredients are commonly taken for preventing or treating thiamine deficiency, beriberi, wernicke-korsakoff syndrome (alcohol-related).Based on those ingredients, 3 medications have a known interaction with it, the most serious rated minor. The ingredients most likely to interact are Thiamine. Use the checker below to test your specific medication, or read the full HelloPharmacist Interaction Report.

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Check Your Meds Against B-1 100 mg Thiamin by Carlson

Ask about any prescription or over-the-counter medication and we check it for interactions with B-1 100 mg Thiamin by Carlson — and tell you which ingredient is responsible.

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HelloPharmacist Scorecard of B-1 100 mg Thiamin by Carlson

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 Jul 11, 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 product contains one active ingredient: thiamine (vitamin B-1) at 100 mg per tablet. Thiamine is an essential B vitamin your body needs to convert food into energy and support nerve and heart function.

The tablet also contains inactive ingredients — dicalcium phosphate, microcrystalline cellulose, croscarmellose sodium, stearic acid, magnesium stearate, silicon dioxide, methylcellulose, and ethylcellulose — which help form and stabilize the pill.

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: energy production and nervous system health.
  • We looked for evidence on: Thiamine deficiency, Wernicke-Korsakoff syndrome (WKS), Fatigue, Cognitive function, Delirium, Dementia — and 3 related terms.
  • The strongest evidence on file: Thiamine is rated "Effective" for Thiamine deficiency (Natural Medicines).
  • Also on file: Thiamine is rated "Effective" for Wernicke-Korsakoff syndrome (WKS).
  • Also on file: Thiamine is rated "Insufficient Reliable Evidence To Rate" for Cognitive function, Dementia, Diabetic neuropathy, Fatigue, and more.

Thiamine is effective for treating thiamine deficiency and Wernicke-Korsakoff syndrome (a serious brain condition caused by severe thiamine lack, often related to heavy alcohol use). It's possibly effective for menstrual cramps (dysmenorrhea).

For mosquito repellent and heart failure, the evidence we hold suggests it's possibly ineffective, so don't count on it for those uses.

The evidence, ingredient by ingredient Thiamine

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.

Thiamine is generally very well tolerated when taken by mouth in normal amounts. Rarely, oral thiamine may cause skin inflammation (dermatitis) or allergic reactions; injected thiamine carries a small risk of severe allergic reactions, but that's not relevant to this tablet form.

Thiamine is needed in pregnancy and while breastfeeding — if you're pregnant or nursing and want to supplement, use only the amount your doctor or midwife recommends.

Side effects, ingredient by ingredient Thiamine

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 — Thiamine.
  • The most serious interaction on file is rated Minor.
  • For scale: 3 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 trimethoprim (Proloprim), let your pharmacist know you're taking this thiamine supplement — it may raise thiamine levels slightly. No other interactions are documented in our data for the thiamine in this product, but check your exact medications with the search tool on this page to be sure.

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.

This is a straightforward thiamine supplement useful if you have a deficiency or Wernicke-Korsakoff syndrome. If you take trimethoprim (an antibiotic), mention this supplement to your pharmacist — it's a minor interaction but worth a quick check.

Anyone pregnant or breastfeeding should talk to their provider before supplementing.

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 Dec 22, 2019.

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 B-1 100 mg Thiamin, straight from the product label.

Brand Carlson
Barcode (UPC) 088395021114
Net contents 100 Tablet(s)
Market status On market
Date entered into DSLD Dec 22, 2019
DSLD ID 209362
Product type Vitamin
Supplement form Tablet Or Pill
Dietary claims / uses Nutrient, All Other, Structure/Function
Intended target group(s) Vegetarian, Adult (18 - 50 Years), Gluten Free, Sugar 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 B-1 100 mg Thiamin by Carlson, 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 Tablet(s)
Maximum serving Sizes:
1 Tablet(s)
UPC/BARCODE
088395021114
IngredientAmount% DV
Thiamine100 mg6667%

Other ingredients: Dicalcium Phosphate, Microcrystalline Cellulose, Croscarmellose Sodium, Stearic Acid, Magnesium Stearate, Silicon Dioxide, Methylcellulose, Ethylcellulose

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.
FDA Statement of Identity

Dietary Supplement

Formulation

Promotes Energy Production & Nervous System Health

Gluten-free Sugar-free

Vegetarian

Suggested/Recommended/Usage/Directions

Directions: Take one tablet daily.

Storage

Keep bottle tightly closed. Store away from heat and moisture.

Formula

B-1 (thiamin) is essential for energy production and nerve health and function.

FDA Disclaimer Statement

This statement has not been evaluated by the FDA. This product is not intended to diagnose, treat, cure, or prevent any disease.

General Statements

Potency & Quality Guaranteed

An FDA Regulated Facility

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

See for yourself

B-1 100 mg Thiamin by Carlson label

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

B-1 100 mg Thiamin 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 B-1 100 mg Thiamin by Carlson

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

Serving size1 Tablet(s) Dosage formTablet Or Pill Amounts shown are per serving.

Thiamine

Interacts with
3 drugs
100 mg per serving Form: Thiamine Hydrochloride, Vitamin B1

Thiamine (vitamin B1) is an essential nutrient your body needs to turn food into energy and to keep your nerves and heart healthy. Most people get eno...

Thiamine monograph & interactions

Other (inactive) ingredients: Dicalcium Phosphate, Microcrystalline Cellulose, Croscarmellose Sodium, Stearic Acid, Magnesium Stearate, Silicon Dioxide, Methylcellulose, Ethylcellulose. These complete the product’s ingredient list but are not active constituents.

Interaction report

B-1 100 mg Thiamin by Carlson Drug Interactions

Want to check YOUR meds against B-1 100 mg Thiamin?

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
3Drugs
3 Minor

Ingredients driving the most interactions

Thiamine 3

Individual Drug Interactions

The ingredients in B-1 100 mg Thiamin interact with 3 drugs. Click any drug to see the details.

1 of the 1 ingredient in B-1 100 mg Thiamin interact with drugs. Each result below shows which ingredient is responsible. Thiamine

Each ingredient & the kinds of drugs it affects

For each ingredient in B-1 100 mg Thiamin 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.

Thiamine1 drug type · 3 drugs

Trimethoprim (Proloprim)

Trimethoprim might increase blood levels of thiamine.
In vitro, animal, and clinical research suggest that trimethoprim inhibits intestinal thiamine transporter ThTR-2, hepatic transporter OCT1, and renal transporters OCT2, MATE1, and MATE2, resulting in paradoxically increased thiamine plasma concentrations.

Likelihood Probable Evidence B
Thiamine full monograph & interactions
The maker

Brand information

Manufacturer and brand details for B-1 100 mg Thiamin, from the product label.

Carlson

See all Carlson products
Name
Carlson Division of J.R. Carlson Laboratories, Inc.
City
Arlington Heights
State
IL
ZipCode
60004
Phone Number
888-234-5656
Web Address
www.carlsonlabs.com
Pharmacist Counseling Corner

B-1 100 mg Thiamin by Carlson: Common Questions

Does B-1 100 mg Thiamin by Carlson interact with any medications?
Yes. Based on its ingredients, B-1 100 mg Thiamin has a known interaction with 3 medications. Use the checker to see how it interacts with a specific drug.
How can one product interact with so many drugs?
B-1 100 mg Thiamin 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 if I'm low on B vitamins?
This product contains only thiamine (B-1), not a full B-complex. It's effective for thiamine deficiency specifically. If you need other B vitamins, you'd need a different product or a multivitamin.
Is thiamine safe to take every day?
Yes, thiamine is generally very safe when taken by mouth in normal amounts like this 100 mg dose. It's a water-soluble vitamin, so your body excretes excess amounts.
Can I take this if I'm pregnant or breastfeeding?
Thiamine is needed in pregnancy and while breastfeeding. The safety rating is Likely Safe, but use only the supplement amount your doctor or midwife advises rather than megadoses.
What is Wernicke-Korsakoff syndrome and why is thiamine effective for it?
Wernicke-Korsakoff syndrome is a serious brain condition caused by severe thiamine deficiency, often from heavy alcohol use. Thiamine replacement is proven effective for treating it.
Will this repel mosquitoes?
No — the evidence we hold suggests thiamine is possibly ineffective as a mosquito repellent, so don't count on it for that.

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

Not sure if B-1 100 mg Thiamin is safe with your meds?

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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.

B-1 100 mg Thiamin label
Go deeper

The Full Monographs Behind B-1 100 mg Thiamin’s Ingredients

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

Herb & supplement monograph

Thiamine

Interacts with 3 drugs

Thiamine (vitamin B1) is an essential nutrient your body needs to turn food into energy and to keep your nerves and heart healthy. Most people get enough from food, but supplements are clear...

Read the full Thiamine monograph →
Sources

Sources & How We Checked

B-1 100 mg Thiamin'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 7 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.

Thiamine 7 references
  1. McEvoy GK, ed. AHFS Drug Information. Bethesda, MD: American Society of Health-System Pharmacists, 1998.
  2. Yates AA, Schlicker SA, Suitor CW. Dietary reference intakes: The new basis for recommendations for calcium and related nutrients, B vitamins, and choline. J Am Diet Assoc 1998;98:699-706. PubMed
  3. 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
  4. Rogovik, A. L., Vohra, S., and Goldman, R. D. Safety considerations and potential interactions of vitamins: should vitamins be considered drugs? Ann.Pharmacother. 2010;44(2):311-324. PubMed
  5. Arruti N, Bernedo N, Audicana MT, Villarreal O, Uriel O, Muñoz D. Systemic allergic dermatitis caused by thiamine after iontophoresis. Contact Dermatitis. 2013 Dec;69(6):375-6. PubMed
  6. Thiamine hydrochloride injection package insert. Lake Zurich, IL: Fresenius Kabi, LLC; September 2019.
  7. Vora B, Wen A, Yee SW, et al. The Effect of Trimethoprim on Thiamine Absorption: A Transporter-Mediated Drug-Nutrient Interaction. Clin Pharmacol Ther 2023;114(2):381-392.

See these in context on the Thiamine 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

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