Thiamine is a vitamin, also called vitamin B1. Vitamin B1 is found in many foods including yeast, cereal grains, beans, nuts, and meat. It is often used in combination with other B vitamins, and found in many vitamin B complex products. Vitamin B complexes generally include vitamin B1 (thiamine), vitamin B2 (riboflavin), vitamin B3 (niacin/niacinamide), vitamin B5 (pantothenic acid), vitamin B6 (pyridoxine), vitamin B12 (cyanocobalamin), and folic acid. However, some products do not contain all of these ingredients and some may include others, such as biotin, para-aminobenzoic acid (PABA), choline bitartrate, and inositol.
Vitamin B1, also called thiamine, is a B complex vitamin. It is found in many foods and is vitally important to keeping a body operating properly.
“Thiamine is involved in many body functions including the nervous system, heart and muscles,” said Dr. Sherry Ross, gynecologist and Women’sHealth Expert at Providence Saint John’s Health Center in Santa Monica, California. “It is also important in the flow of electrolytes in and out of nerve and muscle cells, enzymatic processes and carbohydrate metabolism.”
According to the University of Maryland Medical Center (UMM), thiamine was named B1 because it was the first B complex vitamin to be discovered. According to the Mayo Clinic, it was also one of the first vitamins of any kind ever be classified.
People take thiamine for conditions related to low levels of thiamine (thiamine deficiency syndromes), including beriberi and inflammation of the nerves (neuritis) associated with pellagra or pregnancy.
Thiamine is also used for digestive problems including poor appetite, ulcerative colitis, and ongoing diarrhea.
Thiamine is also used for AIDS and boosting the immune system, diabetic pain, heart disease, alcoholism, aging, a type of brain damage called cerebellar syndrome, canker sores, vision problems such as cataracts and glaucoma, motion sickness, and improving athletic performance. Other uses include preventing cervical cancer and progression of kidney disease in patients with type 2 diabetes.
Some people use thiamine for maintaining a positive mental attitude; enhancing learning abilities; increasing energy; fighting stress; and preventing memory loss, including Alzheimer’s disease.
Healthcare providers give thiamine shots for a memory disorder called Wernicke’s encephalopathy syndrome, other thiamine deficiency syndromes in critically ill people, alcohol withdrawal, and coma.
How effective is it?
Natural Medicines Comprehensive Database rates effectiveness based on scientific evidence according to the following scale: Effective, Likely Effective, Possibly Effective, Possibly Ineffective, Likely Ineffective, Ineffective, and Insufficient Evidence to Rate.
The effectiveness ratings for THIAMINE (VITAMIN B1) are as follows:
- Metabolic disorders. Taking thiamine by mouth helps correct metabolic disorders associated with genetic diseases, including Leigh’s disease, maple syrup urine disease, and others.
- Thiamine deficiency. Taking thiamine by mouth helps prevent and treat thiamine deficiency.
- Brain disorder due to thiamine deficiency (Wernicke-Korsakoff syndrome). Thiamine helps decrease the risk and symptoms of a specific brain disorder called Wernicke-Korsakoff syndrome (WKS). This brain disorder is related to low levels of thiamine (thiamine deficiency) and is often seen in alcoholics. Between 30% and 80% of alcoholics are believed to have thiamine deficiency. Giving thiamine shots seems to help decrease the risk of developing WKS and decrease symptoms of WKS during alcohol withdrawal.
Possibly effective for…
- Cataracts. High thiamine intake as part of the diet is associated with a reduced risk of developing cataracts.
- Kidney disease in people with diabetes. Early research shows that taking high-dose thiamine (100 mg three times daily) for 3 months decreases the amount of albumin in the urine in people with type 2 diabetes. Albumin in the urine is an indication of kidney damage.
- Painful menstruation (dysmenorrhea). Early research suggests that taking thiamine for 90 days stops pain associated with menstruation in girls 12-21 years-old.
Possibly ineffective for…
- Repelling mosquitos. Some research shows that taking B vitamins, including thiamine, does not help repel mosquitos.
Insufficient evidence to rate effectiveness for…
- Athletic performance. Some research suggests that taking thiamine together with pantethine and pantothenic acid (vitamin B5) does not improve muscle strength or endurance in athletes.
- Preventing cervical cancer. Some research suggests that increasing intake of thiamine from dietary and supplement sources, along with other folic acid, riboflavin, and vitamin B12, might decrease the risk of precancerous spots on the cervix.
- Poor appetite.
- Ulcerative colitis.
- Chronic diarrhea.
- Stomach problems.
- Brain conditions.
- Heart disease.
- Canker sores.
- Other conditions.
More evidence is needed to rate thiamine for these uses.
How does it work?
Are there safety concerns?
Thiamine might not properly enter the body in some people who have liver problems, drink a lot of alcohol, or have other conditions.
Special precautions & warnings:
Pregnancy and breast-feeding: Thiamine is LIKELY SAFE for pregnant or breast-feeding women when taken in the recommended amount of 1.4 mg daily. Not enough is known about the safety of using larger amounts during pregnancy or breast-feeding.
Are there interactions with medications?
- It is not known if this product interacts with any medicines.
Before taking this product, talk with your health professional if you take any medications.
Are there interactions with herbs and supplements?
- Areca (betel) nuts change thiamine chemically so it doesn’t work as well. Regular, long-term chewing of betel nuts may contribute to thiamine deficiency.
- Horsetail (Equisetum) contains a chemical that can destroy thiamine in the stomach, possibly leading to thiamine deficiency. The Canadian government requires that equisetum-containing products be certified free of this chemical. Stay on the safe side, and don’t use horsetail if you are at risk for thiamine deficiency.
Are there interactions with foods?
- Coffee and tea
- Chemicals in coffee and tea called tannins can react with thiamine, converting it to a form that is difficult for the body to take in. This could lead to thiamine deficiency. Interestingly, thiamine deficiency has been found in a group of people in rural Thailand who drink large amounts of tea (>1 liter per day) or chew fermented tea leaves long-term. However, this effect hasn’t been found in Western populations, despite regular tea use. Researchers think the interaction between coffee and tea and thiamine may not be important unless the diet is low in thiamine or vitamin C. Vitamin C seems to prevent the interaction between thiamine and the tannins in coffee and tea.
- Raw freshwater fish and shellfish contain chemicals that destroy thiamine. Eating a lot of raw fish or shellfish can contribute to thiamine deficiency. However, cooked fish and seafood are OK. They don’t have any effect on thiamine, since cooking destroys the chemicals that harm thiamine.
What dose is used?
- 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.
- For reducing the risk of getting cataracts: a daily dietary intake of approximately 10 mg of thiamine.
As a dietary supplement in adults, 1-2 mg of thiamine per day is commonly used. The daily recommended dietary allowances (RDAs) of thiamine are: Infants 0-6 months, 0.2 mg; infants 7-12 months, 0.3 mg; children 1-3 years, 0.5 mg; children 4-8 years, 0.6 mg; boys 9-13 years, 0.9 mg; men 14 years and older, 1.2 mg; girls 9-13 years, 0.9 mg; women 14-18 years, 1 mg; women over 18 years, 1.1 mg; pregnant women, 1.4 mg; and breast-feeding women, 1.5 mg.
- Healthcare providers give thiamine shots for treating and preventing symptoms of alcohol withdrawal (Wernicke-Korsakoff syndrome).
To learn more about how this article was written, please see the Natural Medicines Comprehensive Database methodology.