Vitamin
Thiamin (Vitamin B1)
Also known as: Thiamine, Thiamine Mononitrate, Vitamin B1
Thiamin is an essential B vitamin required for carbohydrate metabolism, nerve function, and energy production. It plays a critical role in converting glucose into usable cellular energy.
Last reviewed June 2026 · Evidence graded from peer-reviewed research, not editorial opinion. Educational only — not medical advice.
Every Thiamin (Vitamin B1) product we have scored
| # | Product | Score | Per serving |
|---|---|---|---|
| 1 | Thorne Craving and Stress Support | 93 A | $1.33 |
| 2 | Pure Encapsulations B-Complex liquid | 91 A | $1.34 |
| 3 | Nature Made B-Complex with C Caplets | 90 A | $0.11 |
| 4 | Complement Gut Nurture | 89 A | $1.93 |
| 5 | Nutricost Pre-Workout For Women Powder | 89 A | $0.73 |
| 6 | Nutricost Pre-Workout Complex | 89 A | $0.83 |
| 7 | Garden of Life Vitamin Code Raw B-Complex | 89 A | $0.50 |
| 8 | Thorne Advanced Nutrients | 88 A | $2.40 |
| 9 | Thorne Basic Nutrients 2/Day | 88 A | $0.60 |
| 10 | Thorne Basic Prenatal | 88 A | $1.23 |
| 11 | Thorne Men's Multi 50+ | 88 A | $1.87 |
| 12 | Garden of Life Vitamin Code 50 & Wiser Women | 87 A | $1.01 |
Scored on dose accuracy, form, label transparency and third-party testing. Per-serving cost is list price divided by servings per container. No brand pays to be listed or ranked.
Common questions
How much Thiamin (Vitamin B1) should I take?
The typical range is 1.1–1.2 mg daily (RDA for adults). Daily supplementation for chronic support; therapeutic doses may vary
When should I take Thiamin (Vitamin B1)?
With meals preferred. May be taken with or without food; absorption enhanced with food.
Which form of Thiamin (Vitamin B1) is best?
Thiamine Mononitrate. Other forms in the catalog: Thiamine Hydrochloride, Thiamine Pyrophosphate.
Is Thiamin (Vitamin B1) safe?
Commonly reported: Very rare; occasional skin reactions at high doses.
Which Thiamin (Vitamin B1) supplement scores highest?
Thorne Craving and Stress Support, at 93/100. Scored on dose accuracy, form, label transparency and third-party testing — no brand pays to be listed or ranked.
Daily target & upper limit
1.2 mg / dayThiamin (Vitamin B1) has an established daily reference intake. See best forms, label synonyms, upper-limit warnings, and top-scoring supplements:
Thiamin (Vitamin B1) dosage reference →Primary uses
- Energy metabolism support
- Nervous system function
- Carbohydrate metabolism
- Thiamin deficiency prevention
What systematic reviews concluded
Outcomes that systematic reviews of Thiamin (Vitamin B1) reached a verdict on: 6 with a benefit, 2 with no effect, 8 unclear. Each is quoted from a review and linked to it on PubMed. How these were read.
Reviews found a benefit (6)
“Thiamin was associated with a reduction in in-hospital mortality and the use of renal replacement therapy in patients with septic shock.” PMID 41277404
“Supplementation of septic and septic shock patients with HAT therapy has significant beneficial effects on SOFA score over 72 hours, duration of exogenous vasopressor infusion and procalcitonin clearance.” PMID 38265393
“insufficient thiamine (B1) intake yielded a 33% higher likelihood of severe periodontitis (p < 0.05)” PMID 40218924
“Additionally, studies have demonstrated that thiamine supplementation in AUD patients, even in the absence of thiamine deficit, leads to improvements in cognitive function.” PMID 39818490
“supplementation with thiamine has been shown to improve cardiac function, urine output, weight loss, and signs and symptoms of HF.” PMID 23910704
“Timely treatment with high doses of thiamine can adequately treat Wericke's Encephalopathy.” PMID 32957818
Reviews found no effect (2)
“Our meta-analysis indicates that thiamine supplementation does not have a direct therapeutic effect on CHF, except for correcting TD.” PMID 38940395
“but that they have no clear effect on mortality.” PMID 27898998
Not enough to say: diabetes and cardiovascular complications; stuttering symptoms; alcohol-related peripheral neuropathy; peripheral neuropathy symptoms; tumor growth; dysmenorrhoea symptoms; premenstrual syndrome psychological symptoms; dry eye disease symptoms.
5 findings from reviews in specific patient groups (such as cancer, pregnancy or surgery) are not shown here.
How it works
- Cofactor in pyruvate dehydrogenase complex for energy metabolism
- Essential for transketolase in pentose phosphate pathway
- Required for myelin formation in nervous system
Dosage
- Typical range
- 1.1–1.2 mg daily (RDA for adults)
- Timing
- With meals preferred
- With food
- May be taken with or without food; absorption enhanced with food
- Duration
- Daily supplementation for chronic support; therapeutic doses may vary
- Special populations
- Pregnant/lactating women: 1.4 mg daily; higher doses used therapeutically for Wernicke-Korsakoff syndrome
Forms
- Thiamine Mononitrate· 70/100
- Thiamine Hydrochloride· 70/100
- Thiamine Pyrophosphate· 70/100
Safety
Common side effects
- Very rare; occasional skin reactions at high doses
Contraindications
- None at nutritional doses; use cautiously in those with known thiamin allergy
Products containing Thiamin (Vitamin B1)
Top-scoring supplements in our catalog that list Thiamin (Vitamin B1) on the label. Each product is graded on Formulate's ingredient-level rubric — dose accuracy, form, transparency, and third-party testing.
Evidence notes
Thiamin is an essential micronutrient with extensive clinical evidence supporting its role in metabolism and neurological function. Deficiency prevention and treatment are well-established.
Grade A: Multiple well-designed human trials support the main claims.
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Medical disclaimer. This page is educational and does not replace advice from a qualified healthcare provider. Individual needs and risks vary — consult a professional before starting, stopping, or combining supplements, especially if you are pregnant or nursing, taking medication, or managing a health condition.