Uses

Vitamin B1 is is a water-soluble vitamin needed to process carbohydrates, fat, and protein. Every cell of the body requires vitamin B1 to form the fuel the body runs on—adenosine triphosphate (ATP). Nerve cells require vitamin B1 in order to function normally.

What Are Star Ratings?

Our proprietary “Star-Rating” system was developed to help you easily understand the amount of scientific support behind each supplement in relation to a specific health condition. While there is no way to predict whether a vitamin, mineral, or herb will successfully treat or prevent associated health conditions, our unique ratings tell you how well these supplements are understood by the medical community, and whether studies have found them to be effective for other people.

For over a decade, our team has combed through thousands of research articles published in reputable journals. To help you make educated decisions, and to better understand controversial or confusing supplements, our medical experts have digested the science into these three easy-to-follow ratings. We hope this provides you with a helpful resource to make informed decisions towards your health and well-being.

3 Stars Reliable and relatively consistent scientific data showing a substantial health benefit.

2 Stars Contradictory, insufficient, or preliminary studies suggesting a health benefit or minimal health benefit.

1 Star For an herb, supported by traditional use but minimal or no scientific evidence. For a supplement, little scientific support.

This supplement has been used in connection with the following health conditions:

Used for Why
2 Stars
Alzheimer’s Disease
3 grams daily
Supplementing with vitamin B1 might slow Alzheimer’s disease progression in people whose vitamin B1–dependent enzymes have low activity.

Vitamin B1 is involved in nerve transmission in parts of the brain (called cholinergic neurons) that deteriorate in Alzheimer’s disease. The activity of vitamin B1-dependent enzymes has been found to be lower in the brains of people with Alzheimer’s disease. It has therefore been suggested that vitamin B1 supplementation could slow the progression of Alzheimer’s disease. Two double-blind trials have reported small but significant improvements of mental function in people with Alzheimer’s disease who took 3 grams a day of vitamin B1, compared to those who took placebo. However, another double-blind trial using the same amount for a year found no effect on mental function.

2 Stars
Anemia and Genetic Thiamine-Responsive Anemia
10 to 20 mg daily
Rare genetic disorders can cause anemias that may improve with large amounts of supplements such as vitamin B1.

Deficiencies of iron, vitamin B12, and folic acid are the most common nutritional causes of anemia. Although rare, severe deficiencies of several other vitamins and minerals, including vitamin A,vitamin B2,vitamin B6,vitamin C, and copper, can also cause anemia by various mechanisms. Rare genetic disorders can cause anemias that may improve with large amounts of supplements such as vitamin B1.

2 Stars
Hepatitis
100 mg daily
In a preliminary report, three patients with chronic hepatitis B had an improvement in the severity of their hepatitis after supplementing with thiamine (vitamin B1).

In a preliminary report, three patients with chronic hepatitis B had an improvement in the severity of their hepatitis after taking 100 mg of thiamine (vitamin B1) per day.

2 Stars
Low Back Pain (Vitamin B12, Vitamin B6)
Take under medical supervision: 50 to 100 mg each of vitamins B1 and B6, and 250 to 500 mcg of vitamin B12, all taken three times per day
A combination of vitamin B1, vitamin B6, and vitamin B12 may prevent a common type of back pain linked to vertebral syndromes and may reduce the need for anti-inflammatory medications.

A combination of vitamin B1, vitamin B6, and vitamin B12 has proved useful for preventing a relapse of a common type of back pain linked to vertebral syndromes, as well as reducing the amount of anti-inflammatory medications needed to control back pain, according to double-blind trials. Typical amounts used have been 50–100 mg each of vitamins B1 and B6, and 250–500 mcg of vitamin B12, all taken three times per day. Such high amounts of vitamin B6 require supervision by a doctor.

2 Stars
Neuropathy (Vitamin B6)
25 mg vitamin B1 daily, with 50 mg of vitamin B6 daily
Taking vitamin B1 combined with vitamin B6 may improve symptoms of diabetic neuropathy.

A controlled trial in Africa found that supplementing with both vitamin B1 (25 mg per day) and vitamin B6 (50 mg per day) led to significant improvement of symptoms of diabetic neuropathy after four weeks. However, since this was a trial conducted among people in a vitamin B1–deficient developing country, these improvements might not occur in other people with diabetes. Another trial found that combining vitamin B1 (in a special fat-soluble form) and vitamin B6 plus vitamin B12 in high but variable amounts led to improvement in some aspects of diabetic neuropathy in 12 weeks. As a result, some doctors recommend that people with diabetic neuropathy supplement with vitamin B1, though the optimal level of intake remains unknown.

2 Stars
Neuropathy (Vitamin B12)
Refer to label instructions
Taking vitamin B1 combined with vitamin B12 may improve symptoms of diabetic neuropathy.
A controlled trial in Africa found that supplementing with both vitamin B1 (25 mg per day) and vitamin B6 (50 mg per day) led to significant improvement of symptoms of diabetic neuropathy after four weeks. However, since this was a trial conducted among people in a vitamin B1–deficient developing country, these improvements might not occur in other people with diabetes. Another trial found that combining vitamin B1 (in a special fat-soluble form) and vitamin B6 plus vitamin B12 in high but variable amounts led to improvement in some aspects of diabetic neuropathy in 12 weeks. As a result, some doctors recommend that people with diabetic neuropathy supplement with vitamin B1, though the optimal level of intake remains unknown.
2 Stars
Type 1 Diabetes
25 mg daily, with 50 mg of vitamin B6 daily
People with type 1 diabetes may be deficient in vitamin B1. Supplementing with vitamin B1 may restore levels and improve symptoms of diabetic neuropathy.
Blood levels of vitamin B1 (thiamine) have been found to be low in people with type 1 diabetes. A controlled trial in Africa found that supplementing with both vitamin B1 (25 mg per day) and vitamin B6 (50 mg per day) led to significant improvement of symptoms of diabetic nerve damage (neuropathy) after four weeks. However, since this was a trial conducted among people in a vitamin B1–deficient developing country, these improvements might not occur in other people with diabetes. Another trial found that combining vitamin B1 (in a special fat-soluble form) and vitamin B6 plus vitamin B12 in high but variable amounts led to improvement in some aspects of diabetic neuropathy in 12 weeks. As a result, some doctors recommend that people with diabetic neuropathy supplement with vitamin B1, though the optimal level of intake remains unknown.
2 Stars
Type 2 Diabetes and Diabetic Neuropathy (Vitamin B12)
Refer to label instructions
Taking vitamin B1 combined with vitamin B12 may improve symptoms of diabetic neuropathy.
A controlled trial in Africa found that supplementing with both vitamin B1 (25 mg per day) and vitamin B6 (50 mg per day) led to significant improvement of symptoms of diabetic neuropathy after four weeks. However, since this was a trial conducted among people in a vitamin B1–deficient developing country, these improvements might not occur in other people with diabetes. Another trial found that combining vitamin B1 (in a special fat-soluble form) and vitamin B6 plus vitamin B12 in high but variable amounts led to improvement in some aspects of diabetic neuropathy in 12 weeks. As a result, some doctors recommend that people with diabetic neuropathy supplement with vitamin B1, though the optimal level of intake remains unknown.
2 Stars
Type 2 Diabetes and Diabetic Neuropathy (Vitamin B6)
25 mg of vitamin B1 daily, with 50 mg of vitamin B6 daily
Taking vitamin B1 combined with vitamin B6 may improve symptoms of diabetic neuropathy.

A controlled trial in Africa found that supplementing with both vitamin B1 (25 mg per day) and vitamin B6 (50 mg per day) led to significant improvement of symptoms of diabetic neuropathy after four weeks. However, since this was a trial conducted among people in a vitamin B1–deficient developing country, these improvements might not occur in other people with diabetes. Another trial found that combining vitamin B1 (in a special fat-soluble form) and vitamin B6 plus vitamin B12 in high but variable amounts led to improvement in some aspects of diabetic neuropathy in 12 weeks. As a result, some doctors recommend that people with diabetic neuropathy supplement with vitamin B1, though the optimal level of intake remains unknown.

1 Star
Alcohol Withdrawal
Refer to label instructions
Supplementing with vitamin B1 (thiamine) may prevent brain damage and nerve disorders in people with alcoholism, including those withdrawing from alcohol.
Thiamine deficiency is very common among alcoholics, including those who are withdrawing from alcohol. Even short-term thiamine deficiency can cause irreversible damage to the brain and nervous system.
1 Star
Cardiomyopathy and Wet Beri Beri
Refer to label instructions
People with cardiomyopathy caused by severe vitamin B1 deficiency (known as wet beri beri) generally require intravenous vitamin B1, followed by oral supplementation.

The small proportion of people with cardiomyopathy whose disease is due to severe vitamin B1 (thiamine) deficiency (known as wet beri beri) generally require intravenous vitamin B1, followed by oral supplementation. Vitamin B1 does not appear to be helpful for other types of cardiomyopathy. People requiring vitamin B1 for cardiomyopathy must first be diagnosed as having wet beri beri, and treatment must be supervised by a healthcare professional.

1 Star
Dysmenorrhea
Refer to label instructions
Vitamin B1 appears to relieve dysmenorrheal in cases of vitamin B1 deficiency. It is not known whether supplementing would relieve the condition in women who are not deficient.

In a double-blind trial, adolescents living in India who were suffering from dysmenorrhea took 100 mg of vitamin B1 (thiamine) per day for three months. Eighty-seven percent of those treated experienced marked relief of dysmenorrhea symptoms. However, vitamin B1 deficiency is relatively common in India, whereas it is rare in the Western world, except among alcoholics. It is not known whether vitamin B1 supplementation would relieve dysmenorrhea in women who are not B1 deficient.

1 Star
Fibromyalgia
Refer to label instructions
People with fibromyalgia may be deficient in vitamin B1. Supplementing with the vitamin may correct the deficiency and improve symptoms.

Some studies have found low vitamin B1 (thiamine) levels and reduced activity of some thiamine-dependent enzymes among people with fibromyalgia. The clinical significance of these findings remains unknown.

1 Star
HIV and AIDS Support
Refer to label instructions
People with AIDS often have thiamine (vitamin B1) deficiency, which may contribute to some neurological abnormalities, supplementing with the vitamin may help.

In HIV-positive people with B-vitamin deficiency, the use of B-complex vitamin supplements appears to delay progression to and death from AIDS. Thiamine (vitamin B1) deficiency has been identified in nearly one-quarter of people with AIDS. It has been suggested that a thiamine deficiency may contribute to some of the neurological abnormalities that are associated with AIDS. Vitamin B6 deficiency was found in more than one-third of HIV-positive men; vitamin B6 deficiency was associated with decreased immune function in this group. In a population study of HIV-positive people, intake of vitamin B6 at more than twice the recommended dietary allowance (RDA is 2 mg per day for men and 1.6 mg per day for women) was associated with improved survival. Low blood levels of folic acid and vitamin B12 are also common in HIV-positive people.

1 Star
Multiple Sclerosis
Refer to label instructions
Thiamine (vitamin B1) deficiency may contribute to nerve damage. Researchers have found that injections of thiamine or thiamine combined with niacin may reduce symptoms.

Deficiency of thiamine (vitamin B1) may contribute to nerve damage. Many years ago, researchers found that injecting thiamine into the spinal cord or using intravenous thiamine combined with niacin in people with MS led to a reduction in symptoms. Using injectable vitamins requires medical supervision. No research has yet studied the effects of oral supplementation with B vitamins in people with MS.

1 Star
Pre- and Post-Surgery Health
Refer to label instructions
Vitamin B1, given as intramuscular injections before surgery, resulted in less reduction of immune system activity after surgery in one study.

Vitamin B1, given as intramuscular injections of 120 mg daily for several days before surgery, resulted in less reduction of immune system activity after surgery in a preliminary trial. In a controlled trial, an oral B vitamin combination providing 100 mg of B1, 200 mg of vitamin B6, and 200 mcg of vitamin B12 daily given for five weeks before surgery and for two weeks following surgery also prevented post-surgical reductions in immune activity. However, no research has explored any other benefits of B vitamin supplementation in surgery patients.

How It Works

How to Use It

While the ideal intake is uncertain, one study reported the healthiest people consumed more than 9 mg per day.1 The amount found in many multivitamin supplements (20–25 mg) is more than adequate for most people.

Vitamin B1 is nontoxic, even in very high amounts.

Where to Find It

Wheat germ, whole wheat, peas, beans, enriched flour, fish, peanuts, and meat are all good sources of vitamin B1.

Possible Deficiencies

A decline in vitamin B1 levels occurs with age, irrespective of medical condition.2 Deficiency is most commonly found in alcoholics, people with malabsorption conditions, and those eating a very poor diet. It is also common in children with congenital heart disease.3 People with chronic fatigue syndrome may also be deficient in vitamin B1.4 , 5 Individuals undergoing regular kidney dialysis may develop severe vitamin B1 deficiency, which can result in potentially fatal complications.6 Persons receiving dialysis should discuss the need for vitamin B1 supplementation with their physician.

Best Form to Take

There is no clear evidence to suggest that either thiamine hydrochloride or thiamine nitrate—the two most commonly used supplement forms of thiamine—is preferable to the other. However, lipid-soluble derivatives of thiamine, such as thiamine propyl disulfide, thiamine tetrahydrofurfuryl disulfide, and benfotiamine, are reported to be more bioavailable than water-soluble thiamine, and have been used to treat diabetic neuropathy, myalgia, and some other conditions.7

Interactions

Interactions with Supplements, Foods, & Other Compounds

Vitamin B1 works hand in hand with vitamin B2 and vitamin B3. Therefore, nutritionists usually suggest that vitamin B1 be taken as part of a B-complex vitamin or other multivitamin supplement.

Interactions with Medicines

Certain medicines interact with this supplement.

Types of interactions: Beneficial Adverse Check

Replenish Depleted Nutrients

  • Bumetanide

    People with congestive heart failure (CHF) treated with the loop diuretic furosemide may be at risk for vitamin B1 deficiency due to: 1) the disease, 2) treatment with furosemide, and/or 3) inadequate dietary vitamin B1 intake. In a study of people with CHF, long-term furosemide therapy was associated with clinically significant vitamin B1 deficiency due to urinary losses. This furosemide-induced vitamin B1 deficiency may worsen heart function in patients with CHF and may be prevented or corrected with vitamin B1 supplementation.

  • Desogestrel-Ethinyl Estradiol

    A review of literature suggests that women who use oral contraceptives may experience decreased vitamin B1, B2, B3, B12, C, and zinc levels. Oral contraceptive use has been associated with increased absorption of calcium and copper and with increased blood levels of copper and vitamin A. Oral contraceptives may interfere with manganese absorption. The clinical importance of these actions remains unclear.

  • Ethinyl Estradiol and Levonorgestrel

    A review of literature suggests that women who use oral contraceptives may experience decreased vitamin B1, B2, B3, B12, C, and zinc levels. Oral contraceptive use has been associated with increased absorption of calcium and copper and with increased blood levels of copper and vitamin A.Oral contraceptives may interfere with manganese absorption. The clinical importance of these actions remains unclear.

  • Ethinyl Estradiol and Norethindrone

    A review of literature suggests that women who use OCs may experience decreased vitamin B1, B2, B3, B12, C, and zinc levels. OC use has been associated with increased absorption of calcium and copper and with increased blood levels of copper and vitamin A.OCs may interfere with manganese absorption. The clinical importance of these actions remains unclear.

  • Ethinyl Estradiol and Norgestimate

    A review of literature suggests that women who use OCs may experience decreased vitamin B1, B2, B3, B12, C, and zinc levels. OC use has been associated with increased absorption of calcium and copper and with increased blood levels of copper and vitamin A. OCs may interfere with manganese absorption. The clinical importance of these actions remains unclear.

  • Ethinyl Estradiol and Norgestrel

    A review of literature suggests that women who use oral contraceptives may experience decreased vitamin B1, B2, B3, B12, C, and zinc levels. Oral contraceptive use has been associated with increased absorption of calcium and copper and with increased blood levels of copper and vitamin A. Oral contraceptives may interfere with manganese absorption. The clinical importance of these actions remains unclear.

  • Furosemide

    People with congestive heart failure (CHF) treated with the loop diuretic furosemide may be at risk for vitamin B1 deficiency due to: 1) the disease, 2) treatment with furosemide, and/or 3) inadequate dietary vitamin B1 intake. In a study of people with CHF, long-term furosemide therapy was associated with clinically significant vitamin B1 deficiency due to urinary losses. This furosemide-induced vitamin B1 deficiency may worsen heart function in patients with CHF and may be prevented or corrected with vitamin B1 supplementation.

  • Levonorgestrel

    A review of literature suggests that women who use oral contraceptives may experience decreased vitamin B1, B2, B3, B12, C, and zinc levels. Oral contraceptive use has been associated with increased absorption of calcium and copper and with increased blood levels of copper and vitamin A. Oral contraceptives may interfere with manganese absorption. The clinical importance of these actions remains unclear.

  • Levonorgestrel-Ethinyl Estrad

    A review of literature suggests that women who use oral contraceptives may experience decreased vitamin B1, B2, B3, B12, C, and zinc levels. Oral contraceptive use has been associated with increased absorption of calcium and copper and with increased blood levels of copper and vitamin A. Oral contraceptives may interfere with manganese absorption. The clinical importance of these actions remains unclear.

  • Mestranol and Norethindrone

    A review of literature suggests that women who use oral contraceptives may experience decreased vitamin B1, B2, B3, B12, C, and zinc levels. Oral contraceptive use has been associated with increased absorption of calcium and copper and with increased blood levels of copper and vitamin A. Oral contraceptives may interfere with manganese absorption. The clinical importance of these actions remains unclear.

  • Norgestimate-Ethinyl Estradiol

    A review of literature suggests that women who use oral contraceptives may experience decreased vitamin B1, B2, B3, B12, C, and zinc levels. Oral contraceptive use has been associated with increased absorption of calcium and copper and with increased blood levels of copper and vitamin A. Oral contraceptives may interfere with manganese absorption. The clinical importance of these actions remains unclear.

  • Torsemide

    People with congestive heart failure (CHF) treated with the loop diuretic furosemide may be at risk for vitamin B1 deficiency due to: 1) the disease, 2) treatment with furosemide, and/or 3) inadequate dietary vitamin B1 intake. In a study of people with CHF, long-term furosemide therapy was associated with clinically significant vitamin B1 deficiency due to urinary losses. This furosemide-induced vitamin B1 deficiency may worsen heart function in patients with CHF and may be prevented or corrected with vitamin B1 supplementation.

Reduce Side Effects

  • Stavudine
    A 30-year-old woman who was taking stavudine developed a rare side effect called lactic acidosis, which was successfully treated with intravenous thiamine. Controlled studies are needed to determine whether lactic acidosis might be prevented if people taking stavudine supplement with vitamin B1. Until more information is available, some health practitioners may recommend supplemental vitamin B1 to individuals taking stavudine.

Support Medicine

  • Amitriptyline

    Giving 10 mg per day each of vitamins B1, B2, and B6 to elderly, depressed persons already on tricyclic antidepressants improved their depression and ability to think more than placebo did. The subjects in this study were institutionalized, so it is unclear if these results apply to persons living at home.

  • Clomipramine

    Giving 10 mg per day each of vitamins B1, B2, and B6 to elderly, depressed persons already on tricyclic antidepressants improved their depression and ability to think more than placebo did. The subjects in this study were institutionalized, so it is unclear if these results apply to persons living at home.

  • Desipramine

    Giving 10 mg per day each of vitamins B1, B2, and B6 to elderly, depressed persons already on tricyclic antidepressants improved their depression and ability to think more than placebo did. The subjects in this study were institutionalized, so it is unclear if these results apply to persons living at home.

    Combination of 6 grams per day L-tryptophan and 1,500 mg per day niacinamide (a form of vitamin B3) with imipramine has shown to be more effective than imipramine alone for people with bipolar disorder. These levels did not improve the effects of imipramine in people with depression. Lower amounts (4 grams per day of L-tryptophan and 1,000 mg per day of niacinamide) did show some tendency to enhance the effect of imipramine.

    The importance of the amount of L-tryptophan was confirmed in other studies, suggesting that if too much L-tryptophan (6 grams per day) is used, it is not beneficial, while levels around 4 grams per day may make tricyclic antidepressants work better.

  • Doxepin

    Giving 10 mg per day each of vitamins B1, B2, and B6 to elderly, depressed persons already on tricyclic antidepressants improved their depression and ability to think more than placebo did. The subjects in this study were institutionalized, so it is unclear if these results apply to persons living at home.

  • Imipramine

    Giving 10 mg per day each of vitamins B1, B2, and B6 to elderly, depressed persons already on tricyclic antidepressants improved their depression and ability to think more than placebo did. The subjects in this study were institutionalized, so it is unclear if these results apply to persons living at home.

  • Nortriptyline

    Giving 10 mg per day each of vitamins B1, B2, and B6 to elderly, depressed persons already on tricyclic antidepressants improved their depression and ability to think more than placebo did. The subjects in this study were institutionalized, so it is unclear if these results apply to persons living at home.

  • Protriptyline

    Giving 10 mg per day each of vitamins B1, B2, and B6 to elderly, depressed persons already on tricyclic antidepressants improved their depression and ability to think more than placebo did. The subjects in this study were institutionalized, so it is unclear if these results apply to persons living at home.

  • Trimipramine

    Giving 10 mg per day each of vitamins B1, B2, and B6 to elderly, depressed persons already on tricyclic antidepressants improved their depression and ability to think more than placebo did. The subjects in this study were institutionalized, so it is unclear if these results apply to persons living at home.

Reduces Effectiveness

  • none

Potential Negative Interaction

  • none

Explanation Required

  • none

The Drug-Nutrient Interactions table may not include every possible interaction. Taking medicines with meals, on an empty stomach, or with alcohol may influence their effects. For details, refer to the manufacturers’ package information as these are not covered in this table. If you take medications, always discuss the potential risks and benefits of adding a supplement with your doctor or pharmacist.

Side Effects

Side Effects

At the time of writing, there were no well-known side effects caused by this supplement.

References

1. Cheraskin E, Ringsdorf WM, Medford FH, Hicks BS. The “ideal” daily vitamin B1 intake. J Oral Med 1978; 33:77-9.

2. Wilkinson TJ, Hanger HC, George PM, Sainsbury R. Is thiamine deficiency in elderly people related to age or co-morbidity? Age Ageing 2000;29:111-6.

3. Shamir R, Dagan O, Abramovitch D, et al. Thiamine deficiency in children with congenital heart disease before and after corrective surgery. JPEN J Parenter Enteral Nutr 2000;24:154-8.

4. Heap LC, Peters TJ, Wessely S. Vitamin B status in patients with chronic fatigue syndrome. J R Soc Med 1999;92:183-5.

5. Grant JE, Veldee MS, Buchwald D. Analysis of dietary intake and selected nutrient concentrations in patients with chronic fatigue syndrome. J Am Diet Assoc 1996;96:383-6.

6. Hung SC, Hung SH, Tarng DC, et al. Thiamine deficiency and unexplained encephalopathy in hemodialysis and peritoneal dialysis patients. Am J Kidney Dis 2001;38:941-7.

7. Gaby, AR. Nutritional Medicine. Concord, NH: Friz Perlberg Publishing, 2011.