Vitamin B1 (Thiamine) | Deficiencies, Excesses and Recommendations

vitamin b1 thiamine supplement

Vitamin B1, also known as thiamine, is essential for the normal functioning of the nervous system, and is needed to metabolize carbohydrates, proteins, and fats.

A shortage of thiamine can impact the function of multiple organ systems.

Thiamine is water soluble, meaning that it is able to be dissolved in water. This means that thiamine doesn’t need to be consumed with a fatty meal in order for it to be available for the body to use.

Vitamin B1 is the only vitamin to contain sulfur. According to a popular educational website:

Sulfur helps the body resist bacteria, cleanses the blood, and protects the protoplasm of cells.

There are many other nutrients that contain sulfur, such as amino acids, and biotin, but these chemicals are not officially classified as vitamins.

Although Vitamin B1 in its natural form is water soluble, thiamine does have a synthetic, fat soluble counterpart named benfotiamine. This is marketed as a drug in some countries, and as a dietary supplement in the United States.

Sulbutiamine is another fat soluble version of the vitamin, designed to increase thiamine levels in the brain. More information about sulbutiamine and benfotiamine is available at the end of this article.

What Could Happen If I Don’t Get Enough Vitamin B1?

  • Fatigue. Thiamine is involved in converting food to energy.
  • Irritability. Vitamin B1 is necessary in order to produce a specific neurotransmitter.
  • Loss of appetite. Thiamine may be involved in the regulation of satiety.
  • Neurological symptoms. Symptoms may include tingling, muscle weakness, difficulty walking, etc.
  • Beriberi. Beriberi is a specific disease of extreme thiamine deficiency that affects the cardiovascular and nervous systems, and produces symptoms ranging from shortness of breath, to difficulty walking and speaking.

Consistently low levels of thiamine over time are associated with impaired glucose control and cognitive dysfunction.

The above symptoms may be signs of other vitamin deficiencies or health issues. Talk to your doctor before purchasing a supplement to address symptoms above.

A thiamine deficiency can occur for reasons other than inadequate intake of the nutrient in the diet. For example, those who have had gastric surgery may be at greater risk. The primary cause of thiamine deficiency in industrialized nations is chronic alcohol consumption.

What Will Happen If I Get Too Much Vitamin B1?

  • Thiamine is relatively non-toxic when obtained through diet and supplements. Most adverse reactions from thiamine happened when using an injectable form of the vitamin.
  • Little information is available regarding the safety of high doses of the fat soluble forms of this vitamin.
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Get plenty of thiamine from your diet by regularly eating beans, peas, lentils, and grains, specifically brown rice. Avoid regular alcohol consumption, which can cause a thiamine deficiency unrelated to dietary intake.

If you choose to take a supplement, we generally recommend using a brand that submits to independent, third-party testing, or has been independently tested and approved by Consumer Labs.

Now Foods Vitamin B-1
Thiamine is involved in numerous body functions, including nervous system and muscle functioning, the flow of electrolytes in and out of nerve and muscle cells, carbohydrate metabolism, and the production of hydrochloric acid, which is necessary for proper digestion.*
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Life Extension Mega Benfotiamine
Benfotiamine supports healthy blood sugar metabolism and may help protect against advanced glycation end products, oxidative stress, and help inhibit inflammatory responses.*
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Potential Life Enhancements


  • May support healthy cognition.
  • May support healthy blood sugar levels.
  • May reduce the risk of developing cataracts when used in combination with a healthy diet and other nutrients. (R)


  • Increases levels of Vitamin B1.
  • May support healthy cognition.
  • May provide protection from harmful effects of smoking cigarettes.
  • May provide comfort during diabetic complications such as neuropathy.


  • May support healthy energy levels
  • May promote wakefulness and reduce fatigue.
  • May support health cognition, and improve concentration.
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