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Buy Vitamin B1 Online
(Thiamine Hydrochloride)

What is Vitamin B1?

What is Vitamin B1?

Vitamin B1 (thiamine hydrochloride) is a water-soluble vitamin and micronutrient found in food sources, such as whole grains, lentils, nuts, and meat. Vitamin B1 is used to treat vitamin B1 deficiency (also known as thiamine deficiency), beriberi (severe thiamine deficiency), Wernicke-Korsakoff syndrome, and some nerve disorders. It may also be used for heart failure, but it is possibly ineffective.

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Purchase Vitamin B1 from Universal Drugstore today and save!

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  • 100mg

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Vitamin B1 (generic Vitamin B1)

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Thiamine Hydrochloride 
100mg

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Important information about Vitamin B1

Vitamin B1 or thiamine is an essential nutrient, and the intake of thiamine is required by our bodies to function properly. When taken orally, vitamin B1 gets absorbed through the gastrointestinal tract. There are different forms of thiamine, like free thiamine found in food becomes the active form thiamine pyrophosphate, also known as thiamine diphosphate, once it enters the human body. Thiamine works to ensure proper digestion of carbohydrates and the use of energy. Thiamine pyrophosphate is a coenzyme for the enzyme erythrocyte transketolase, which is part of glucose metabolism. It also helps to ensure our nervous system works correctly. When someone has a low thiamine status, thiamine supplementation works by replacing the low levels. If you have high thiamine levels, it is removed through urine excretion because vitamin B1 is water-soluble.

Follow all directions given to you by your doctor and read all documents provided, including the full Prescribing Information, FDA-Approved Product Labeling, Instructions for Use, and Medication Guide, before using vitamin B1. However, the following is a synopsis of the general guidelines for the use of vitamin B1:

  • The recommended dietary allowance (RDA) of vitamin B1 for adult males is 1.2 mg daily, and for adult females it is 1.1 mg daily. For children, it depends on their age. Ask your healthcare provider what dose is best for you.
  • Vitamin B1 supplements can be taken by mouth, by subcutaneous injection, or intravenously (IV). Your healthcare professional will know what type of vitamin B1 supplement is best for you based on your vitamin B1 levels.
  • Signs and symptoms of vitamin B1 deficiency include memory loss, fatigue, loss of appetite, peripheral neuropathy, and weight loss. If thiamine deficiency is not treated, it may lead to serious complications such as loss of coordination (ataxia), memory loss, muscle weakness, Wernicke encephalopathy, and cognitive impairment.
  • Risk factors for thiamine deficiency include alcohol use disorder (chronic alcoholism), liver disorder, bariatric surgery, high-dose diuretics, poor diet, anorexia, and hemodialysis.

The most common side effects of vitamin B1 include:

  • Nausea.
  • Headache.

Some individuals may experience serious side effects while using vitamin B1. These side effects may require immediate medical attention. If you experience any of the following, contact your healthcare provider or seek emergency medical help:

  • Allergic reaction. Signs include hives, rash, or swelling of the face, lips, or tongue.

These are not all of the possible side effects of vitamin B1. You should always seek medical advice from your healthcare provider for any questions or concerns about your medical condition or treatment. Read all patient information, medication guides, or drug information sheets that come with this medication. You can also report adverse effects to the Food and Drug Administration at www.fda.gov/medwatch or 1-800-FDA-1088.

Before starting vitamin B1, it is crucial to discuss any existing health conditions with your healthcare provider. You should be sure that your healthcare provider is aware of all your medical conditions, including whether you have:

  • Previous allergic reactions to dietary supplements, food, and any medications.

Allergic reaction to any ingredients in vitamin B1 dietary supplements.

You will start to feel better within a couple of weeks of consistently taking vitamin B1 supplements. It’s important to continue taking vitamin B1 even if you don’t notice a difference, or as advised by your healthcare professional.

When vitamin B1 is taken with other prescription drugs, over-the-counter medications, vitamins, and supplements, it may change how they work or increase the frequency or severity of side effects. Make sure that you tell your healthcare professional about anything that you are taking to avoid any negative drug interactions, including:

  • Trimethoprim.
  • Betel nut.
  • Horsetail.

Vitamin B1 is most commonly available as 100 mg per tablet, but other doses are also available, such as 150 mg, 250 mg, 300 mg, and 500 mg per tablet.

Store vitamin B1 at room temperature, keep away from children and pets.

Multiple pharmaceutical companies manufacture vitamin B1 (thiamine) dietary supplements.

Vitamin B1 (thiamine) is the generic version. Vitamin B1 is often taken with other B vitamins like vitamin B2 (riboflavin), and is found in many vitamin B complex and multivitamin products with vitamin C and magnesium.

Although there are no withdrawal effects associated with vitamin B1, it should not be stopped without talking to your healthcare professional, as it may be treating your low levels of vitamin B1.

Vitamin B1 (thiamine) is likely safe in pregnancy when it is part of your normal diet. The RDA during pregnancy is 1.4 mg daily. Talk to your doctor if you are already pregnant or if you have any plans to become pregnant. They will know or recommend what is best for you.

Vitamin B1 (thiamine) is likely safe in breastfeeding when it is part of your normal diet. The RDA during lactation is 1.4 mg daily. Talk to your doctor if you are already breastfeeding or if you have any plans to breastfeed. They will know or recommend what is best for you.

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Important information about buying Vitamin B1 from UniversalDrugstore™

Once you complete your order, we process, verify, and dispatch your medication. You’ll receive email updates at each stage, including tracking details once your order ships. If any additional documentation is needed (such as a valid prescription), we’ll contact you promptly. Once approved, your order is charged and delivered directly to your doorstep.

Orders are typically processed within 1–3 business days once all required documents are received and approved. Standard delivery times range from 10–18 business days, depending on your location.

Yes! Once your medication ships, you will receive an email with tracking information so you can monitor your shipment every step of the way.

Our Customer Care team is available 24/7 to assist with any order-related concerns or questions. If you experience delays, missing items, or need support, contact us using the details provided in your confirmation email.

All orders are shipped in discreet, plain packaging to protect your privacy. Medications are securely packaged to prevent damage and ensure they arrive in top condition.

Yes. We use cold-chain shipping methods to safely transport temperature-sensitive medications, ensuring they maintain proper storage conditions throughout delivery.

Shipping costs vary depending on your location and shipping method. Free shipping promotions may be available—check the checkout page for the latest offers. Orders above $100 going to a US destination will receive free shipping.

Currently, we do not bill Medicare or Medicaid directly. However, we provide detailed receipts and documentation that you can submit to your insurance provider for potential reimbursement.

Universal Drugstore does not bill private health insurance directly, but we provide a detailed invoice that you can submit to your insurer for possible reimbursement. Many insurers will accept Universal Drugstore’s documents, but if you have any questions, check with your insurance company prior to purchasing.

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Universal Drugstore offers many generic alternatives that provide the same active ingredients at a lower cost. Search for your medication and compare pricing for generic vs. brand-name options. Generic availability depends on the medication.

If your medication requires a prescription, you must upload it online, via email, or fax. Over-the-counter (OTC) medications do not require a prescription. All prescription medication purchases require a valid and approved prescription. The Universal Drugstore customer care team can contact your doctor directly to get your prescription, and ensure all information is up to date.

Yes! You can add multiple medications to your cart, including prescription, OTC, and pet medications, and complete your purchase in a single checkout process.

Yes! If your prescription includes refills, you can reorder quickly by logging into your account and selecting your medication for a hassle-free refill process. Always refill your medication proactively and ontime, to ensure you do not run out of important medication.

Yes! We offer:

  • Up to 80% savings on medications
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We offer 24/7 customer support via phone, email, and chat. Visit our Contact Us page for assistance with ordering, shipping, or medication questions.

Medical Disclaimer

The information, including but not limited to, text, graphics, images and other material contained on this website are for informational purposes to increase health awareness only. No material on this site is intended to be a substitute for professional medical advice, diagnosis or treatment. 



Always seek the advice of your physician or other qualified health care provider with any questions you may have regarding a medical condition or treatment and before undertaking a new health care regimen, and never disregard professional medical advice or delay in seeking it because of something you have read on this website.