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Dietary supplement

B-1 100 mg Ingredients & Drug Interactions

by Basic Vitamins

B-1 100 mg 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 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 is a dietary supplement by Basic Vitamins 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 by Basic Vitamins

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

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HelloPharmacist Scorecard of B-1 100 mg by Basic Vitamins

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 16, 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.

B-1 100 mg is a straightforward B-vitamin supplement: it contains one active ingredient, thiamine (also called vitamin B1), at 100 milligrams per tablet. Thiamine is an essential nutrient your body needs for converting food into energy and supporting nerve and heart function.

The rest of the tablet is made up of inactive ingredients like microcrystalline cellulose and hypromellose that help hold the pill together.

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

This product doesn't appear to be marketed for a specific use, so we graded Thiamine's overall clinical evidence instead.

Strong

Strong clinical evidence supports Thiamine for:

Why this rating?
  • We looked at the product name, claims, and label statements and couldn't find a stated purpose to grade.
  • Since the label doesn't commit to one use, we graded the ingredient's overall clinical evidence instead.
  • On file: Thiamine deficiency — rated "Effective" (Natural Medicines).
  • On file: Wernicke-Korsakoff syndrome (WKS) — rated "Effective" (Natural Medicines).
  • On file: Dysmenorrhea — rated "Possibly Effective" (Natural Medicines).

Thiamine is effective for treating thiamine deficiency and Wernicke-Korsakoff syndrome (a serious neurological condition caused by severe thiamine lack). It's possibly effective for dysmenorrhea (period pain), though the evidence isn't as strong.

The evidence we hold does not support its use as a mosquito repellent or for heart failure.

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. Allergic reactions like dermatitis are rare; if you're given thiamine by injection (not the case here), serious allergic reactions are also rare but possible.

Thiamine is needed during pregnancy and breastfeeding — if you're pregnant or nursing and considering this supplement, use only the doses your doctor or pharmacist recommends for you.

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 (an antibiotic), mention this supplement to your doctor or pharmacist first — it may raise thiamine blood levels slightly. No other interactions are documented for the ingredients we hold data on.

Check your own medication Run your meds through the checker above

The bottom line

Scorecard at a glanceFully disclosed formula with strong clinical evidence behind its ingredients' uses. Only minor medication interactions are documented, and safety information is well characterized.

This product is useful if you're deficient in thiamine or have Wernicke-Korsakoff syndrome and your provider recommends it. If you take trimethoprim or any other prescription medication, check your exact drugs with your doctor or pharmacist before starting — it's a quick step that keeps you covered.

Talk with them about whether this dose is right for your situation.

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 Jun 22, 2023.

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, straight from the product label.

Brand Basic Vitamins
Barcode (UPC) 307610555204
Net contents 100 Tablet(s)
Market status On market
Date entered into DSLD Jun 22, 2023
DSLD ID 292249
Product type Vitamin
Supplement form Tablet Or Pill
Dietary claims / uses All Other
Intended target group(s) 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 B-1 100 mg by Basic Vitamins, 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)
Servings per container
100
UPC/BARCODE
307610555204
IngredientAmount% DV
Thiamine100 mg8333%

Other ingredients: Microcrystalline Cellulose, Croscarmellose Sodium, Hypromellose, Magnesium Stearate, Silicon Dioxide, Polyethylene Glycol, Hydroxypropyl Cellulose, Carnauba Wax

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.
Precautions

Keep out of the reach of children.

Do not use if inner seal is missing or broken.

Warning: If you are pregnant, nursing, taking any medications, consult your doctor before use.

Discontinue use and consult your doctor if any adverse reactions occur.

Storage

Store in a cool, dry place.

Formulation

Gluten free

High quality basics

Contains no: milk, egg, fish, crustacean shellfish, tree nuts, wheat, peanuts, gluten, soybeans and sodium.

FDA Disclaimer Statement

Dietary Supplement

Suggested/Recommended/Usage/Directions

Directions: For adults, take one (1) tablet daily, preferably with a meal.

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

See for yourself

B-1 100 mg by Basic Vitamins label

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

B-1 100 mg 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 by Basic Vitamins

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 Servings per container100 Amounts shown are per serving.

Thiamine

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

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: Microcrystalline Cellulose, Croscarmellose Sodium, Hypromellose, Magnesium Stearate, Silicon Dioxide, Polyethylene Glycol, Hydroxypropyl Cellulose, Carnauba Wax. These complete the product’s ingredient list but are not active constituents.

Interaction report

B-1 100 mg by Basic Vitamins Drug Interactions

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

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 interact with 3 drugs. Click any drug to see the details.

1 of the 1 ingredient in B-1 100 mg 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 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, from the product label.

Basic Vitamins

See all Basic Vitamins products
Name
Basic Drugs, Inc.
City
Vandalia
State
OH
ZipCode
45377
Phone Number
937-898-4010
Web Address
www.basicvitamins.com
Pharmacist Counseling Corner

B-1 100 mg by Basic Vitamins: Common Questions

Does B-1 100 mg by Basic Vitamins interact with any medications?
Yes. Based on its ingredients, B-1 100 mg 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 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.
Is this safe if I'm pregnant or breastfeeding?
Thiamine is needed during both pregnancy and breastfeeding, so this supplement is considered likely safe in those situations. Use only the dose your doctor or pharmacist advises for you — don't take more than recommended.
What is thiamine actually for?
Thiamine (vitamin B1) helps your body convert food into energy and supports your nerves and heart. It's essential — your body can't make it, so you need to get it from food or supplements.
Can I take this if I'm low on B vitamins?
This product is effective for thiamine deficiency specifically. If you're concerned about low B vitamins in general, talk with your doctor — you may benefit from a B-complex that covers multiple B vitamins, or this one alone if thiamine is your only gap.
Are there any side effects?
Thiamine taken by mouth is very safe in normal amounts. Allergic reactions like rashes are rare; serious reactions would only happen if given by injection, which this product is not.
Will this help with period pain?
Thiamine is possibly effective for dysmenorrhea (menstrual pain), though the evidence isn't as strong as it is for deficiency. Talk with your doctor about whether it might help your situation.

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

Not sure if B-1 100 mg 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 label
Go deeper

The Full Monographs Behind B-1 100 mg’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'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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