Thiamin (Vitamin B1)
Also known as Vitamin B1, Thiamine
Thiamin is a water-soluble B vitamin that helps convert the food you eat into energy. It is essential for normal nerve, muscle, and heart function.
Why it matters
What it does in your body
- Energy metabolism of carbohydrates
- Coenzyme for glucose and amino acid breakdown
- Nerve function
- Muscle and heart function
- Production of ATP
By age, sex, and life stage
How much you need
Values are RDAs except for infants, which are Adequate Intakes (AI). Requirements are set in mg/day and rise modestly with age and during pregnancy and lactation.
Recommended intake across life
in mg/dayBars scale to the highest recommendation shown. Where men and women differ, both values are listed.
Full reference table
| Life stage | Male | Female |
|---|---|---|
| Infants 0-6 mo | 0.2 (AI) | 0.2 (AI) |
| Infants 7-12 mo | 0.3 (AI) | 0.3 (AI) |
| Children 1-3 | 0.5 | 0.5 |
| Children 4-8 | 0.6 | 0.6 |
| Children 9-13 | 0.9 | 0.9 |
| Teens 14-18 | 1.2 | 1.0 |
| Adults 19+ | 1.2 | 1.1 |
| Pregnancy | n/a | 1.4 |
| Lactation | n/a | 1.4 |
Values in mg/day. AI marks an Adequate Intake, used when there is not enough evidence for a formal recommendation.
What moves the number
What changes your needs
Age
Needs increase gradually from 0.5 mg/day in early childhood to 1.2 mg/day (men) and 1.1 mg/day (women) in adulthood.
Sex
Adult men need 1.2 mg/day and adult women need 1.1 mg/day.
Body weight / size
Because thiamin supports energy metabolism, needs scale modestly with body size and energy intake.
Pregnancy and lactation
Both pregnancy and lactation raise the requirement to 1.4 mg/day to support the growing baby and milk production.
Alcohol intake
Heavy alcohol use impairs thiamin absorption and use, sharply increasing the risk of deficiency.
Running low
Signs you might not get enough
Most at risk: People with alcohol dependence, older adults, people with HIV/AIDS or diabetes, and those who have had bariatric surgery.
Too much
Can you get too much?
Thiamin is considered non-toxic from food and supplements. Absorption declines rapidly at intakes above about 5 mg and the body excretes any excess in urine, so no UL was established.
Where to get it
Best food sources
The bottom line
Enriched grains, pork, legumes, and fortified cereals make thiamin easy to get. Adults need only 1.1 to 1.2 mg/day, and there is no known risk from getting too much.
Track thiamin (vitamin b1) automatically
Thiamin (Vitamin B1) is one of the 92 nutrients Vora reads from a photo of your meal, so you can see where you stand without weighing or logging by hand.
Sources and method
The recommended intakes, upper limits, and food-source amounts on this page come from the primary references below. Numbers were checked against the current NIH Office of Dietary Supplements fact sheets and the Institute of Medicine (now the National Academies) Dietary Reference Intakes.
- NIH Office of Dietary Supplements, Thiamin Fact Sheet for Health Professionals
- Institute of Medicine (IOM/NASEM), Dietary Reference Intakes for Thiamin, Riboflavin, Niacin, Vitamin B6, Folate, Vitamin B12, Pantothenic Acid, Biotin, and Choline (1998)
This page is for general education, not medical advice. Reference intakes are population averages for healthy people and do not replace guidance from your doctor or a registered dietitian, especially if you are pregnant, managing a health condition, or considering supplements.