Thiamine (Vitamin B1) Uses, Benefits, Dosages & Side Effects,

Thiamine (Thiamin, Vitamin B1) is a B-complex vitamin with many important health roles.

This vitamin helps the body to produce energy, metabolize fats and proteins. It is used in the body in the metabolically active form of thiamin diphosphate (TDP, thiamin pyrophosphate).

Thiamine is also important for liver health, helps to facilitate nervous system function, helps the body handle stress, resist disease, and supports brain health. Thiamine also helps us to maintain eye/vision health, as well as healthy nails, skin and hair.

Like other B vitamins, thiamine is water soluble; meaning that it is not stored inside fat cells in the body. Small amounts of this vitamin are stored in the liver, but it has a short half-life.

We must continuously acquire this essential micronutrient from the foods we eat each day, or by taking a thiamine or B-vitamin complex supplement. [1][2]

This article will review what thiamine is, what it does in the body, its health benefits, supplemental uses, dosages and safety.

Different types of thiamine supplements are also discussed as well as recommended daily intakes, food sources, and possible side effects and interactions of taking Vitamin B1 supplements.

Thiamine

Vitamin B1 Supplement

Energy

Brain Health

Well-Being

How It Works:

• Supports energy production
• Supports healthy nerve function
• Precursor to thiamin diphosphate for glucose metabolism

Dosage:

Between 100 - 500 mg per day

Safety:

Rated Likely Safe

Top Vitamin B1 Products* ❯

View User Ratings* ❯

What is Thiamine?

Thiamine is a water-soluble B vitamin that is also sometimes called aneurine. Thiamine may also be spelled as “thiamin”.

Thiamine is most commonly called vitamin B1 because it was the first B-complex vitamin to be discovered. It was first discovered in the late 1890s and was later the first vitamin to be isolated in 1926. In 1936, it was first produced synthetically. [1]

Thiamine’s scientific name is 3-((4-Amino-2-methyl-5-pyrimidinyl)methyl)-5-(2- hydroxyethyl)-4-methylthiazolium chloride. It has a chemical formula of C12H17N4OS+. [2]

According to the Linus Pauling Institute (LPI), this vitamin occurs in the body as free thiamine, but is more prevalent in phosphorylated forms such as:

• thiamin monophosphate (TMP)
• thiamin triphosphate (TTP)
• thiamin pyrophosphate (TPP) or thiamin diphosphate [2]

Thiamine is an essential nutrient meaning that it is not produced in the body and must be obtained through the diet or supplements. Although the body does not store significant amounts, it is concentrated in muscle tissues after intestinal absorption. [2]

Thiamine deficiency is rare in developed countries today because of food quality and quantity, as well as the fact that many foods are fortified with this vitamin. Deficiency is most commonly seen developing countries.

Japan was previously reported to have high rates of deficiency, which may be linked to high consumption of polished white rice. Use of germ rice has since resulted in improved thiamine status in the Japanese population.

Mild thiamine deficiency can cause symptoms such as weight loss, irritability, poor memory, confusion, fatigue, and general malaise (feeling of being unwell).

More severe deficiency can cause many different disorders including beriberi and Wernicke-Korsakoff syndrome. [3] Serious cases of beriberi have resulted in mortality.

Uses for Thiamine

The Natural Medicines Comprehensive Database (NMCD) states that thiamine is used orally for preventing and treating syndromes associated with thiamine deficiency including beriberi, peripheral neuritis associated with pellagra, and neuritis of pregnancy. [4]

According to NMCD, thiamine supplements are also taken orally for: [4]

• Diabetic neuropathy
• Enhancing learning abilities
• Increasing energy
• Maintaining a positive mental attitude
• Memory loss including Alzheimer’s disease
• Postherpetic neuralgia (nerve pain) and itch
• Preventing cervical cancer
• Prevention of West Nile virus
• Slowing progression of nephropathy in patients with type 2 diabetes
• Vision problems such as cataracts and glaucoma

Thiamine is also used orally for AIDS, heart disease, chronic diarrhea, GI disorders, poor appetite, alcoholism, stress and aging. Other oral uses include canker sores, motion sickness, and repelling mosquitoes. [4]

Sometimes doctors administer thiamine intramuscularly or intravenously for a severe neurological disease called Wernicke’s encephalopathy syndrome caused by deficiency of this vitamin. [4]

Thiamine can also be injected for thiamine deficiency in critically-ill patients, acute alcohol withdrawal, and hypothermia or coma from unknown origin. [4]

Note that common uses for thiamine are not the same as proven health benefits. Evidence for thiamine in specific health conditions will be discussed in the “Benefits” section below.

How Does Thiamine Work in the Body?

According to the LPI, “Thiamine plays an important role in helping the body convert carbohydrates and fat into energy. It is essential for normal growth and development and helps to maintain proper functioning of the heart and the nervous and digestive systems.” [2]

ATP (adenosine triphosphate) is a complex organic chemical that is used as the body’s main energy source. Thiamine and ATP react to form an active coenzyme called TPP (thiamine pyrophosphate). [5]

LPI states that, “Thiamin pyrophosphate (TPP), the active form of thiamin, is involved in several enzyme functions associated with the metabolism of carbohydrates, branched-chain amino acids, and fatty acids.” [2]

The Office of Dietary Supplements at the Natural Institutes of Health in the United States further explains that this compound is an essential cofactor for five different enzymes that are responsible for glucose, fat, and amino acid metabolism.

According to PubChem, Thiamine pyrophosphate is required for carbohydrate metabolism, specifically for converting glucose (sugar) found in the blood into a usable form of energy in the cells.

This compound is necessary for the actions of pyruvate dehydrogenase and alpha-ketoglutarate as well as for transketolase, an enzyme involved in the pentose phosphate pathway. [5]

Effects & Mechanisms

According to the Linus Pauling Institute (LPI), in research studies Thiamine has demonstrated glucose-regulating, mood-modulating, antioxidant (works against free radicals), and erythropoietic (stimulates red blood cell production) properties. [2]

According to the Open Chemistry Database on PubChem, thiamine also has anti-atherosclerotic (prevents formation of plaque in blood vessels) and detoxification activities.

It is also commonly proposed to have some ergogenic effects (enhances physical performance, stamina, or recovery in exercise or sports). [5]

Researchers are beginning to investigate the effects of supplementing with this vitamin for cardiovascular health. Thiamine has been shown to inhibit damaging effects of glucose and insulin on smooth muscle endothelial cells in arteries.

It is hypothesized that by inhibiting endothelial cell proliferation, this vitamin might help to reduce the risk for developing atherosclerosis (“clogged” arteries caused by plaque buildup). More research is needed to understand this mechanism. [5]

In rats, thiamine has been shown to protect liver and kidney cells from lead-induced lipid (fat) peroxidation (oxidative degradation). It is not clear whether it can protect kidney and liver cells in humans yet. [5]

Thiamine Deficiency

Although rare in developed countries, thiamine deficiency can result from:

• Excessive thiamine loss
• Inadequate dietary intake
• Inadequate provision in parenteral nutrition
• Increased metabolic requirements
• Reduced gastrointestinal absorption [5]

In industrialized countries, alcohol consumption is a major contributor to thiamine deficiency. The NMCD states that about 55% of alcoholics are believed to be deficient. [4]

Severe deficiency can cause beriberi, a disease that affects multiple organs, as well as the central nervous system (CNS) and peripheral nervous system (PNS). [5]

In some cases, thiamine deficiency can cause a secondary disorder called Wernicke-Korsakoff syndrome (WKS). WKS is marked by various neurological symptoms that present in two phases.

Initially, a person with WKS may experience ocular disturbances (ophthalmoplegia), unsteady stance/gait (ataxia), and/or confusion. [4]

In advanced stages, WKS can cause anterograde amnesia, and variable presentation of retrograde amnesia. This can lead to severe memory impairment without necessarily causing a change in intellectual capacities. [4]

Dietary deficiency and decreased levels of activity in thiamine-dependent enzymes may contribute to Alzheimer’s disease. [5]

However, LPI states, “Although thiamin supplementation markedly reverses cognitive impairment in animal models of thiamin deficiency, the effect of thiamin supplementation in Alzheimer’s disease patients is not yet known.” [2]

The NMCD reports that the elderly may be at higher risk for developing subclinical thiamine deficiency, however this has not yet been demonstrated in research trials. [2]

Thiamine Health Benefits

The NMCD rates Thiamine as Effective for preventing and treating thiamine deficiency, treating certain metabolic disorders, and preventing Wernicke-Korsakoff syndrome. [4]

Injectable thiamine that is used for severe nutrient deficiencies is an FDA approved prescription medication.

Additionally, the NMCD rates Thiamine as Possibly Effective for preventing cataracts, dysmenorrhea (painful menstruation), and diabetic nephropathy (kidney disease related to diabetes). [4]

There have been some clinical trials conducted using thiamine supplements for these conditions showing positive results. More research is still needed to confirm the therapeutic efficacy of this vitamin for these conditions.

Thiamine Deficiency

NMCD states that use of an oral thiamine supplement can prevent and treat thiamine deficiency syndromes. This can include beriberi as well as peripheral neuritis associated with pellagra pregnancy. [4]

Neuritis is more commonly known as neuropathy. It refers to inflammation of peripheral nerves, which can result in pain and a loss of functionality.

Metabolic Disorders

Oral administration of Vitamin B1 supplements helps to temporarily normalize certain metabolic disorders.

These include genetic diseases like SNE (subacute necrotizing encephalopathy), branched-chain aminoacidopathy (maple syrup urine disease), lactic acidosis linked to hyperalaninemia (high serum alanine), and hepatic (liver) pyruvate carboxylase deficiency. [4]

Wernicke-Korsakoff Syndrome

Wernicke-Korsakoff syndrome (WKS) is a condition that results from thiamine deficiency. It consists of Wernicke encephalopathy and Korsakoff syndrome, two separate conditions that commonly occur together.

The LPI states that these conditions cause brain damage, psychosis, and impaired thalamus and hypothalamus function resulting permanent memory issues. [2]

Symptoms of this condition can include loss of mental activity, confusion, visual impairment, ataxia (loss of muscle coordination), loss of memory, hallucinations, alcohol withdrawal and confabulation.

WKS is most commonly seen in alcoholics, with research estimating that between 30-80% of alcohol abusers have some biochemical signs or clinical symptoms of the condition. It may also occur following a chronic illness or after bariatric surgery for weight loss.

The NMCD reports that parenteral (outside mouth and alimentary canal, ex. injections) administration of thiamine seems to reduce the risk of developing WKS and to improve symptoms of WKS in cases of acute alcohol withdrawal. [4]

Dysmenorrhea

Dysmenorrhea refers to very painful, “crampy” menstruation cycles. While most women experience some pain and discomfort during their menstrual cycle, it is often worse in women with dysmenorrhea, and typically not relieved by non-steroidal anti-inflammatory drug (NSAID) pain relievers.

The NMCD states, “Preliminary clinical research suggests that taking thiamine hydrochloride 100 mg daily for 90 days eliminates pain in 87% of adolescent and adult women with moderate to severe primary dysmenorrhea.” [4]

In another preliminary human study, 100 mg thiamine, alone or with 500 mg fish oil, daily for sixty days moderately reduced pain intensity and duration in adolescent females with dysmenorrhea relative to placebo controls. [4]

These results are promising, but more research is still needed to determine the therapeutic efficacy of thiamine for dysmenorrhea.

Speak with your doctor if you have dysmenorrhea and are interested in learning more about thiamine products.

Cataracts

Cataracts refer to clouding of the eye lens, which can result in decreased visual ability. Data from population research associates high daily intake of thiamine from food sources with a 40% lower chance for developing nuclear cataracts.

Other population research associated high dietary thiamine with modestly-decreased risk for age-related lens opacification. [4] These epidemiological studies establish correlation, but not causation.

Research is limited at this time, and more studies are needed to determine the effect of thiamine supplementation on eye health.

Diabetic Nephropathy

Preliminary clinical research suggests that thiamine may help to avoid diabetic nephropathy, which is a general term for kidney deterioration or diabetic kidney disease.

Albumin is a blood protein that serves as a marker for organ damage. Increases in urinary albumin can be an early sign of vascular or kidney damage.

The NMCD reports that taking 100 mg thiamine, 3 times daily for 3 months, “significantly decreases urinary albumin excretion in patients with type 2 diabetes compared to placebo.” [4]

Further study is still needed to fully understand the effects of thiamine supplementation on diabetics for nephropathy and other conditions.

Additional Health Benefits

Thiamine supplements are sometimes used for prediabetes (impaired glucose tolerance), cervical cancer, and herpes zoster virus (shingles). [4]

At this time, there is very limited clinical research available to evaluate the use of vitamin B1 for these conditions. More research is still needed to determine the therapeutic efficacy of supplementation for these conditions.

Impaired Glucose Tolerance

In one preliminary clinical study, taking 100 mg thiamine three times daily for 6 weeks modestly decreased plasma glucose levels two hours after eating meals compared to baseline levels in people with impaired glucose tolerance (prediabetes). [4]

Cervical Cancer

According to the NMCD, “Epidemiological evidence suggests that increasing intake of thiamine from dietary and supplement sources, along with folic acid, riboflavin, and vitamin B12, is associated with a lower odds of precancerous cervical lesions.” [4]

Shingles

In one human trial, 100 mg injected under the skin 6 times weekly for 4 weeks reduced itchiness by at least 30%, in more than 65% of tested patients with herpes zoster. However, this vitamin seems to have no effect on herpes zoster pain. [4]

The FDA has not approved thiamine as a drug for the prevention or treatment of any of these medical conditions. More research is needed to determine whether this supplement works or not.

Thiamine Dosage Guidelines

The recommended dietary intake for this vitamin varies depending on age, weight, sex, health status, dietary intake of other nutrients, activity levels and more.

MedLine reports the following RDAs (recommended dietary allowances) for thiamine intake in the diet:

• 0.2 mg/day for infants between 0-6 months of age
• 0.3 mg/day for infants 7-12 months
• 0.5 mg/day for children between 1-5 years
• 0.6 mg/day for children between 4-8 years
• 0.9 mg/day for children between 9-13 years
• 1 mg/day for females 14-18 years
• 1.1 mg/day for women over 18
• 1.2 mg/day for males over 14 years
• 1.4 mg/day for pregnant women
• 1.5 mg/day for breastfeeding women [5]

According to MedLine, “For adults with somewhat low levels of thiamine in their body (mild thiamine deficiency): the usual dose of thiamine is 5-30 mg daily in either a single dose or divided doses for one month. The typical dose for severe deficiency can be up to 300 mg per day.” [6]

Daily dietary intake of at least 10 mg is recommended by some doctors for preventing nuclear cataracts. [6]

When taken as a dietary supplement, 100 mg of thiamine is the most common dosage of many single ingredient products available. When included in a multivitamin, levels are typically lower, often between 25-50 mg per dosage.

In research studies, vitamin B1 has been used in varying dosages for different conditions:

• Cataracts: 10 mg per day
• Diabetic neuropathy: 100 mg 3 times per day for 3 months
• Dysmenorrhea: 100 mg per day for 2-3 months
• Impaired glucose tolerance: 100 mg 3 times per day for 6 weeks [4]

The Linus Pauling Institute states that consuming a varied daily diet will provide most people with enough thiamine for their physiological needs. [5]

Thiamine Foods and Supplements

The LPI reports that whole grain foods, yeast, lean pork, beans, nuts, and legumes are some of the richest sources of this vitamin. [2]

Some good food sources and their respective Vitamin B1 content include: [5]

• ½-cup boiled spinach: 0.09 mg
• ½-cup boiled lentils: 0.17 mg
• 1 cup long-grain brown rice, cooked: 0.19 mg
• 1-ounce pecans, raw: 0.19 mg
• 1 cup fortified puffed wheat breakfast cereal: 0.31 mg
• 3 oz lean roasted pork tenderloin: 0.81 mg
• 1 cup toasted, plain wheat germ: 1.88 mg

When possible, it is recommended to get your nutrients from food sources and by eating a rich and varied diet. In some cases, this is not possible and use of supplements will be necessary.

Supplements should be used to enrich a healthy diet, not to replace a healthy diet.

The University of Maryland Medical Center (UMM) states that thiamine is sold alone, in B-complex vitamin supplements, and in multivitamin products.

Vitamin B1 is available in softgels, gelcaps, chewable tablets, liquid drops, tablets, and lozenges. In supplements, this ingredient is normally listed as thiamine mononitrate or thiamine hydrochloride. [1]

As a single ingredient, thiamine is most commonly found in 100 mg formulations, although larger 300 mg and 500 mg formulations are available. In B-complex multivitamins, it is normally provided in smaller amounts, typically between 25-50 mg per dosage.

NMCD reports there are more than 7500 dietary supplement products that contain thiamine as a sole or combination ingredient. Look for non-GMO, organic, and certified toxin-free supplements. [4]

PubChem states that thiamine is highly susceptible to atmospheric oxidation, and heat degradation. Therefore, it is recommended to store supplements in a dark, cool location, in a tightly-sealed container. Do not freeze this product. [5]

Sulbutiamine

Sulbutiamine is a modified form of thiamine that is purported to have better absorption in the body and greater ability to penetrate the blood-brain barrier.

It is a synthetic compound that is composed of two Vitamin B1 molecules bound together by a sulfur group. Due to this modification, it is fat-soluble and is well absorbed from the intestines into the bloodstream.

This supplement is commonly used as a nootropic due to its purported ability to enhance energy levels, support memory, mood and cognitive performance.

Sulbutiamine (Arcalion, Ereon, isobutyryl thiamine disulfide) was initially developed in Japan as a drug to combat thiamine deficiency.

It has also been used clinically in France for the treatment of asthenia, which involves symptoms of weakness and fatigue. However, research did not demonstrate significant results and it is no longer widely used.

Thiamine Safety and Side Effects

The NMCD rates thiamine as Likely Safe when used orally or intravenously and appropriately. Oral use for women during pregnancy and lactation is also rated as Likely Safe. [4]

Thiamine is generally well tolerated and does not usually cause adverse reactions. Large dosages may cause dermatitis, stomach upset, or allergic reactions. [1]

The UMM states, “Taking any one of the B vitamins for a long period of time can result in an imbalance of other important B vitamins. For this reason, you may want to take a B-complex vitamin, which includes all the B vitamins.” [1]

It is always recommended that you speak with your doctor before beginning any new supplements. Your doctor will be able to help determine an appropriate dosage for your needs and give suggestions to help avoid side effects.

Supplement and Drug Interactions

The following herbs and foods can affect thiamine levels and/or activities in the body: [2]

• Areca (betel) nuts
• Coffee and tea
• Horsetail (Equisetum)
• Raw seafood

Some medications that can affect thiamine levels include: [4]

• Adrucil (fluorouracil)
• Antibiotic drugs
• Contraceptive drugs
• Dilantin (phenytoin)
• Diuretic drugs
• Glucophage (metformin)

Use of this supplement might affect lab tests that measure levels of serum theophylline, uric acid, and urobilinogen. [4]

Ask your doctor if thiamine is safe for you if you have liver cirrhosis, alcoholism, critical illness, or a nutrient malabsorption disorder. [4] Those receiving hemodialysis may need to take a Vitamin B1 supplement to avoid deficiency. [4]

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