What is B1? Uses, warnings & side effects

Updated May 14, 2025  •  Published Apr 8, 2021

B1 overview

BRAND NAMES:

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

Generic Names:

  • B1

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 B1 used for?

What form(s) does B1 come in?

  • Tablet

  • Capsule

  • Liquid

What are common B1 dosages?

  • Bottle 100 Tablets

B1 images - What does B1 look like?

  • B1
    100 tablets bottle

How to take B1

  • 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 B1

  • You should not use two doses at the same time.

  • 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.

B1 contraindications - Who shouldn't take B1?

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

B1 warnings

  • Tell your doctor if you are pregnant or breastfeeding, or if you become pregnant.

  • Swelling of face, lips or eyelids

B1 interactions & what to avoid when taking B1

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

B1 side effects - How does B1 make you feel?

Serious Side Effects

  • Swelling of face, lips or eyelids

  • Itching or trouble breathing