What is Vitamin B1 (Thiamine): Uses, Warnings & Interactions

What is Vitamin B1 (Thiamine): Uses, Warnings & Interactions

Updated May 14, 2025 • Published Dec 30, 2020

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Vitamin B1 (Thiamine) overview

BRAND NAMES:

Optimum Vitamin B-1, Sundown Naturals B1, Sundown Naturals B1, Vitamin B1 AvPak, Sundown Naturals B1

Generic Names:

Thiamine Hcl

Uses:

Thiamine, another name for Vitamin B-1, is used to treat thiamine-deficiency (not enough thiamine in the body).

Therapeutic Classes:

Nutriceutical, Nutritive Agent

Forms:

Tablet, Capsule, Liquid

How it’s taken:

By mouth

What is Vitamin B1 (Thiamine) used for?

What form(s) does Vitamin B1 (Thiamine) come in

Tablet
Capsule
Liquid

What are common Vitamin B1 (Thiamine) doses?

Bottle 100 Tablets
Bottle 110 Tablets

Common Vitamin B1 (Thiamine) prescriptions

B-1
100 tablets bottle
B-1
110 tablets bottle

How to take Vitamin B1 (Thiamine)

Your doctor will tell you how much and when to take your medicine. Keep all medicine away from children.
You may take your medicine with or without food.
Measure your oral liquid medicine using a marked measuring spoon or medicine cup.
Your doctor will tell you how much and when to take your medicine. Keep all medicine away from children.
You may take your medicine with or without food.
Measure your oral liquid medicine using a marked measuring spoon or medicine cup.
Missing a dose is generally not a cause for concern.

What to do if you miss a dose of Vitamin B1 (Thiamine)

Take the missed dose as soon as possible.
Skip the missed dose if it is almost time for your next dose.
Missing a dose is generally not a cause for concern.
You should not use two doses at the same time.

Vitamin B1 (Thiamine) contraindications

You should not use this medicine if you have had an allergic reaction to thiamine (Vitamin B-1).

Vitamin B1 (Thiamine) warnings

Tell your doctor if you are pregnant or breastfeeding, or if you become pregnant.
Swelling of face, lips or eyelids

Vitamin B1 (Thiamine) interactions

Follow your doctor's orders if he or she has given you a special diet.

Vitamin B1 (Thiamine) side effects

Serious Side Effects

Swelling of face, lips or eyelids
Itching or trouble breathing