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Dietary supplement

Thiamin Vitamin B-1 100 mg Ingredients & Drug Interactions

by Geri-Care

Thiamin Vitamin 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 Thiamin Vitamin 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

Thiamin Vitamin B-1 100 mg is a dietary supplement by Geri-Care 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 Thiamin Vitamin B-1 100 mg by Geri-Care

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

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HelloPharmacist Scorecard of Thiamin Vitamin B-1 100 mg by Geri-Care

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 (also called vitamin B-1), at 100 mg per tablet. Thiamine is an essential B vitamin your body needs to turn food into energy and support your nervous system.

The tablet also contains several inactive ingredients—cellulose, croscarmellose sodium, hypromellose, magnesium stearate, silica, dicalcium phosphate, and stearic acid—which are fillers and binders that help form and stabilize the tablet.

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 (WKS), a serious brain condition caused by severe thiamine lack. It's possibly effective for dysmenorrhea (painful periods).

For heart failure and mosquito repellent uses, the evidence suggests it's possibly ineffective. If you're taking this for a specific condition, talk with your pharmacist about whether the evidence supports your reason.

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 safe when taken by mouth in normal amounts. Allergic reactions like dermatitis are rare when taken orally, though injected thiamine can rarely cause more serious allergic responses.

Thiamine is needed in pregnancy and while breastfeeding, but you should use supplement doses only as your doctor or midwife advises—don't exceed recommended amounts without guidance.

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—it's a Minor interaction that can raise your thiamine blood levels. Check your other medications with the search tool on this page before starting, even though we have documented information only for trimethoprim.

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 straightforward for replacing low thiamine or treating deficiency-related conditions. If you take trimethoprim (an antibiotic), mention this supplement to your pharmacist so they can monitor your thiamine levels.

For any other prescription medications, check them with the tool on this page first.

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

Brand Geri-Care
Barcode (UPC) 357896851019
Net contents 100 Tablet(s)
Market status On market
Date entered into DSLD Jun 22, 2023
DSLD ID 291968
Product type Vitamin
Supplement form Tablet Or Pill
Dietary claims / uses All Other
Intended target group(s) Adult (18 - 50 Years)
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 Thiamin Vitamin B-1 100 mg by Geri-Care, 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
357896851019
IngredientAmount% DV
Thiamine100 mg8333%

Other ingredients: Cellulose, Croscarmellose Sodium, Hypromellose, Magnesium Stearate, Silica, Dicalcium Phosphate, Stearic Acid

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

Suggested/Recommended/Usage/Directions

Suggested Use: Adults-One tablet daily as a dietary supplement, preferably with a meal, or as recommended by your health professional.

Precautions

As with any supplement, if you are pregnant, nursing, or taking medication, ask a health professional before use.

Tamper Evident: Do not use if imprinted seal under cap is missing or broken.

Keep out of reach of children Package not child resistant

Storage

Store at room temperature

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

See for yourself

Thiamin Vitamin B-1 100 mg by Geri-Care label

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

Thiamin Vitamin 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 Thiamin Vitamin B-1 100 mg by Geri-Care

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: 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: Cellulose, Croscarmellose Sodium, Hypromellose, Magnesium Stearate, Silica, Dicalcium Phosphate, Stearic Acid. These complete the product’s ingredient list but are not active constituents.

Interaction report

Thiamin Vitamin B-1 100 mg by Geri-Care Drug Interactions

Want to check YOUR meds against Thiamin Vitamin 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 Thiamin Vitamin B-1 100 mg interact with 3 drugs. Click any drug to see the details.

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

Geri-Care

See all Geri-Care products
Name
Geri-Care Pharmaceuticals Corp.
Street Address
1650 63rd Street
City
Brooklyn
State
NY
ZipCode
11204
Pharmacist Counseling Corner

Thiamin Vitamin B-1 100 mg by Geri-Care: Common Questions

Does Thiamin Vitamin B-1 100 mg by Geri-Care interact with any medications?
Yes. Based on its ingredients, Thiamin Vitamin 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?
Thiamin Vitamin 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 thiamine safe to take during pregnancy or while breastfeeding?
Thiamine is likely safe and actually needed during both pregnancy and breastfeeding. Use only the supplement dose your doctor or midwife recommends—don't go above that without asking them first.
What is thiamine actually used for?
It's effective for treating thiamine deficiency and Wernicke-Korsakoff syndrome, a serious brain condition. It's possibly effective for painful periods. For other uses like heart failure, the evidence doesn't support it.
Can thiamine cause allergic reactions?
Allergic reactions when you take thiamine by mouth are rare, though dermatitis and other skin reactions occasionally happen. Injectable thiamine is more likely to cause serious allergic reactions, but those are also uncommon.
I take trimethoprim for a urinary tract infection. Is this supplement safe with it?
It's a Minor interaction—trimethoprim can raise your thiamine blood levels. Your pharmacist should know you're taking both so they can keep an eye on your levels if needed.

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

Not sure if Thiamin Vitamin 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.

Thiamin Vitamin B-1 100 mg label
Go deeper

The Full Monographs Behind Thiamin Vitamin 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

Thiamin Vitamin 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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