Thiamin, or vitamin B1, is a water-soluble vitamin with a critical role in energy metabolism, and so in the growth, development and function of cells1.
Its active form, thiamin diphosphate (TDP), is a cofactor for five enzymes in glucose, amino acid and fat metabolism1.
Needed for the growth, development and function of cells1.
Deficiency (beriberi) mainly damages peripheral nerves, impairing sensory, motor and reflex function1.
Early deficiency can bring cardiovascular symptoms such as an enlarged heart1.
Severe deficiency is linked with Wernicke-Korsakoff syndrome, which affects memory and orientation1.
Intestinal phosphatases free thiamin from its phosphorylated food forms, and it is absorbed by active transport at food doses and by passive diffusion at high doses1. In cells, thiamin pyrophosphokinase turns it into TDP, the cofactor of enzymes such as pyruvate dehydrogenase and transketolase2. The body stores only small amounts, mainly in the liver, and excretes the excess in urine1.
| Food and serving | Amount |
|---|---|
| Breakfast cereal, fortified with 100% of the DV, 1 serving | 1.2 mg |
| Egg noodles, enriched, cooked, 1 cup | 0.5 mg |
| Black beans, boiled, ½ cup | 0.4 mg |
| English muffin, plain, enriched, 1 | 0.3 mg |
| Macaroni, whole wheat, cooked, 1 cup | 0.2 mg |
| Acorn squash, baked, ½ cup | 0.2 mg |
| Brown rice, not enriched, cooked, ½ cup | 0.2 mg |
| Sunflower seeds, toasted, 1 oz | 0.1 mg |
| Food and serving | Amount |
|---|---|
| Pork chop, bone in, broiled, 3 oz | 0.4 mg |
| Trout, cooked, 3 oz | 0.4 mg |
| Mussels, blue, cooked, 3 oz | 0.3 mg |
| Tuna, bluefin, cooked, 3 oz | 0.2 mg |
| Beef steak, bottom round, braised, 3 oz | 0.1 mg |
Heat and cooking water cut thiamin: bread has 20–30% less than its raw ingredients, and unless white rice is enriched it has a tenth of the thiamin in brown rice1. Amounts per serving from1.
Breads, cereals and infant formulas are fortified in the U.S. and many other countries, and about half of U.S. thiamin intake comes from added thiamin1.
Multivitamins usually include thiamin, and B-complex and thiamin-only products are also sold1.
The body stores little thiamin, mainly in the liver, and it has a short half-life, so it needs a steady supply from food1.
The same reference table draws the reference lines on your charts in Ayuvo. Needs differ in pregnancy and breastfeeding, which are not covered here.
| Age | Women | Men |
|---|---|---|
| 19–30 | 1.1 mg | 1.2 mg |
| 31–50 | 1.1 mg | 1.2 mg |
| 51–70 | 1.1 mg | 1.2 mg |
| 71+ | 1.1 mg | 1.2 mg |
RDA (Recommended Dietary Allowance) is the daily amount that meets the needs of nearly all healthy people. Per day, for adults1.
Signs like these have many possible causes. They are a reason to talk to a clinician, not to self-treat.
Deficiency can come from low intake or from poor absorption or higher losses, for example with alcohol dependence, some medicines or bariatric surgery1.
No upper limit is set because no adverse effects have been reported from high intakes from food or supplements; the body excretes the excess in urine1.
Blood thiamin levels are not reliable status markers, so status is often measured indirectly by the activity of transketolase, a TDP-dependent enzyme in red blood cells, with and without added TDP1.
| TDP effect | What it may mean |
|---|---|
| 0–15% | Typical in healthy people |
| 15–25% | Marginal deficiency |
| Above 25% | Deficiency |
Labs use different units and ranges. Your clinician reads a result alongside your history and other tests.
Thiamin is in many multivitamins and B-complex products; the most common forms are thiamin mononitrate and thiamin hydrochloride1.
A stable, water-soluble form widely used in supplements1.
Also stable and water soluble, and one of the two most common forms1.
A synthetic derivative that is not water soluble and is converted to thiamin in the body1.
Supplements can interact with medicines. Talk to a clinician or pharmacist before you start one, especially at high doses.
Beriberi is the classic result of thiamin deficiency. It mainly causes nerve damage and muscle wasting, with problems in sensation, movement and reflexes, and in rare cases heart failure. It is rare where breads and cereals are enriched, but it still occurs.
Alcohol reduces how much thiamin the gut absorbs, lowers liver stores and interferes with turning thiamin into its active form, and people with alcohol dependence often eat too little. Chronic alcohol use is the most common cause of thiamin deficiency in industrialized countries.
Yes. Processing lowers thiamin, so unenriched white rice has about a tenth of the thiamin in brown rice. Enriched white rice has thiamin added back, though in U.S. food tables a serving still has less than brown rice.
Food logging does not estimate thiamin, so Ayuvo tracks it from supplements you log in Medications, and from Apple Health on iPhone or Health Connect on Android when another app saves it there. Charts by day, week, month and year use the reference lines from this page, personalised by age and sex where they differ. Free, with no account.
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Facts on this page come from these sources, checked on the dates shown. Intake numbers come from Ayuvo's shared reference table, which cites the sources marked for them.
General information, not medical advice. This guide is for healthy adults and does not cover pregnancy, breastfeeding, children or medical conditions. It cannot diagnose or treat anything. Talk to a clinician before starting high-dose supplements, or if you think you may have too little or too much of a nutrient. Spotted an error? Email us.