Vitamin B-1

Vitamin B-1
Vitamin B-1
Vitamin B-1, also known as thiamine, is an essential vitamin that helps convert food into energy and is important for brain and nervous system function. It plays a crucial role in maintaining overall health and is found in foods like grains, beans, and meat.
Active Ingredient: Thiamine
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Side Effects

This vitamin usually has no side effects. If you have any unusual effects, contact your doctor or pharmacist promptly.

A very serious allergic reaction to this drug is rare. However, get medical help right away if you notice any symptoms of a serious allergic reaction, including: rash, itching/swelling (especially of the face/tongue/throat), severe dizziness, trouble breathing.

This is not a complete list of possible side effects. If you notice other effects not listed above, contact your doctor or pharmacist.

Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088 or at

In Canada – Call your doctor for medical advice about side effects. You may report side effects to Health Canada at 1-866-234-2345.

How long does it take for this medicine to take effect?

The onset of action for thiamine supplementation can vary depending on the individual's nutritional status and the reason for supplementation. For individuals with thiamine deficiency, symptomatic improvements (e.g., reduction in symptoms of beriberi) can be observed within a few days of starting supplementation. However, for general supplementation without significant deficiency, the effects on well-being may be more subtle and gradual.

How long do the effects of this medicine last?

As a water-soluble vitamin, thiamine is not stored in large quantities in the body and is excreted in the urine. This necessitates regular daily intake to maintain adequate levels. The duration of the effects of a single dose of thiamine will vary, but maintaining consistent levels requires daily supplementation or dietary intake.

Is it safe to consume alcohol while taking this medicine?

Alcohol consumption can negatively affect thiamine absorption and utilization and can lead to thiamine deficiency, particularly in individuals with chronic alcoholism. This condition, known as Wernicke-Korsakoff syndrome, is a serious neurological disorder. It is safe to consume alcohol in moderation while taking thiamine supplements, but individuals at risk for or with a history of alcohol abuse should be particularly cautious about their thiamine intake.

Is this a habit forming medicine?

Thiamine is not habit-forming and does not have the potential for abuse or dependence. It is an essential nutrient required for normal bodily function.

Can this medicine be taken during pregnancy?

Thiamine is considered safe and necessary during pregnancy. Adequate thiamine intake is crucial for maternal health and fetal development. Thiamine deficiency during pregnancy can lead to complications, and supplementation is often recommended to ensure that the nutritional needs of the mother and the developing fetus are met.

Can this medicine be taken while breast-feeding?

Thiamine is also safe and important during breastfeeding. It passes into breast milk and is essential for the health and development of the nursing infant. Nursing mothers should ensure they have adequate thiamine intake to support their health and their infant's nutritional needs.


Thiamine (vitamin B1) is used to prevent or treat low levels of vitamin B1 in people who do not get enough of the vitamin from their diets. Most people who eat a normal diet do not need extra vitamin B1. However, some conditions (such as alcoholism, cirrhosis, stomach/intestinal problems) can cause low levels of vitamin B1. Vitamin B1 plays an important role in the body. It is needed to maintain the health of the nerves and the heart. Low levels of vitamin B1 may cause heart failure and mental/nerve problems.

How to use Vitamin B-1

Take this vitamin by mouth with or without food, usually 1 to 3 times daily. Follow all directions on the product package, or take as directed by your doctor. If you have any questions, ask your doctor or pharmacist.

The dosage is based on your medical condition and response to treatment.

Use this vitamin regularly to get the most benefit from it. To help you remember, take it at the same time(s) each day.

Tell your doctor if your condition lasts or gets worse. If you think you may have a serious medical problem, get medical help right away.


Before taking thiamine, tell your doctor or pharmacist if you are allergic to it; or if you have any other allergies. This product may contain inactive ingredients, which can cause allergic reactions or other problems. Talk to your pharmacist for more details.

Before having surgery, tell your doctor or dentist about all the products you use (including prescription drugs, nonprescription drugs, and herbal products).

During pregnancy, this vitamin has been found to be safe when used in recommended doses. Higher doses during pregnancy should be used only when clearly needed. Discuss the risks and benefits with your doctor.

This vitamin passes into breast milk and is considered to be safe during breast-feeding when used in recommended doses. Consult your doctor for more information.


If someone has overdosed and has serious symptoms such as passing out or trouble breathing, call 911. Otherwise, call a poison control center right away. US residents can call their local poison control center at 1-800-222-1222. Canada residents can call a provincial poison control center.

Lab and/or medical tests (such as thiamine levels) may be done while you are using this medication. Keep all medical and lab appointments. Consult your doctor for more details.

This product is not a substitute for a proper diet. It is best to get your vitamins from healthy foods. Thiamine is commonly found in cereal grains, bread, pork, and beans, among others. Consult your doctor, pharmacist, or nutritionist for more details.

If you miss a dose, take it as soon as you remember. If it is near the time of the next dose, skip the missed dose. Take your next dose at the regular time. Do not double the dose to catch up.

Different brands of this vitamin have different storage needs. Check the product package for instructions on how to store your brand, or ask your pharmacist. Do not store in the bathroom. Keep all medications away from children and pets.

Do not flush medications down the toilet or pour them into a drain unless instructed to do so. Properly discard this product when it is expired or no longer needed. Consult your pharmacist or local waste disposal company.


Drug interactions may change how your medications work or increase your risk for serious side effects. This document does not contain all possible drug interactions. Keep a list of all the products you use (including prescription/nonprescription drugs and herbal products) and share it with your doctor and pharmacist. Do not start, stop, or change the dosage of any medicines without your doctor's approval.

This vitamin may interfere with certain lab tests (such as uric acid levels, urobilinogen urine test), possibly causing false test results. Make sure lab personnel and all your doctors know you use this vitamin.

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