Vitamin B1 (thiamin)
Full ranking Dose tool Products (4,416)
Key facts
Sources: https://ods.od.nih.gov/factsheets/Thiamin-HealthProfessional/ · FDA DV 1.2 mg (https://www.fda.gov/food/nutrition-facts-label/daily-value-nutrition-and-supplement-facts-labels); pre-2016 DV [1.5] (https://www.federalregister.gov/documents/2016/05/27/2016-11867/food-labeling-revision-of-the-nutrition-and-supplement-facts-labels); no UL set
Daily dose across products (mg/day)
Label data from official national databases and brand websites, as declared; not lab-verified.
Common forms
| Form | Products | Median | P5–P95 | Elemental fraction |
|---|---|---|---|---|
| Thiamin HCl | 2107 | 10 mg | 0.38 – 125 | — |
| Thiamin mononitrate | 1268 | 2.5 mg | 0.05 – 100 | — |
| Benfotiamine | 142 | 50 mg | 3 – 150 | — |
Common questions
What is the Daily Value for Vitamin B1 (thiamin)?
The US FDA Daily Value for adults and children aged 4 and over is 1.2 mg. It is a labelling reference, not a personal recommendation. [source]
How much Vitamin B1 (thiamin) do products usually contain per day?
As of 2026-11-01, 4,416 products list a comparable daily dose (4,463 dose records; one product can have several). The median is 5 mg per day, and 90% of records fall between 0.14 and 100 mg. Figures come from labels and are not lab-tested. [source]
What are the side effects of Vitamin B1 (thiamin)?
Thiamin (vitamin B1) has not been shown to cause any harm. (Source: NIH ODS) [source]
What happens if you take too much Vitamin B1 (thiamin)?
No UL has been set because no harm from high intakes has been shown. (Source: NIH ODS) [source]
Is Vitamin B1 (thiamin) safe during pregnancy and breastfeeding?
The recommended amount is 1.4 mg a day in both pregnancy and breastfeeding. (Source: NIH ODS) [source]
Does Vitamin B1 (thiamin) interact with medications or other supplements?
Furosemide (Lasix) and the chemotherapy drug fluorouracil can lower thiamin levels in the body. (Source: NIH ODS) [source]
Top ranked
| Rank | Brand | Product | Per day | Score |
|---|---|---|---|---|
| 1 | Swanson | Vitamin B1 100 mg | 100 mg | 100.0 |
| 2 | CVS Health | B1 100 mg | 100 mg | 97.8 |
| 2 | Nature's Bounty | Vitamin B-1 100 mg | 100 mg | 97.8 |
| 2 | The Vitamin Shoppe | Vitamin B1 100 mg | 100 mg | 97.8 |
| 5 | Nature's Way | Vitamin B-1 100 mg Thiamin HCl | 100 mg | 94.4 |