Vitamin
Thiamine (Vitamin B1)
Also known as: vitamin B1, thiamin, thiamine HCl, thiamine pyrophosphate
Water-soluble B vitamin essential for energy metabolism and nervous system function. Acts as a coenzyme in carbohydrate metabolism and neurotransmitter synthesis.
Last reviewed June 2026 · Evidence graded from peer-reviewed research, not editorial opinion. Educational only — not medical advice.
Every Thiamine (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 Thiamine (Vitamin B1) should I take?
The typical range is 1.1 mg daily RDA (women 50+: 1.1 mg); supplements typically 25-100 mg. Safe for long-term daily use. Water-soluble excess is excreted in urine.
When should I take Thiamine (Vitamin B1)?
With meals to enhance absorption. Absorption enhanced with food; may cause GI upset on empty stomach.
Which form of Thiamine (Vitamin B1) is best?
thiamine HCl. Other forms in the catalog: thiamine mononitrate, thiamine pyrophosphate (TTFD).
Is Thiamine (Vitamin B1) safe?
Commonly reported: Rare at recommended doses, Very high doses may cause nausea, headache, or irritability.
Which Thiamine (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 / dayThiamine (Vitamin B1) has an established daily reference intake. See best forms, label synonyms, upper-limit warnings, and top-scoring supplements:
Thiamine (Vitamin B1) dosage reference →Primary uses
- Energy metabolism
- Nervous system function
- Brain health and cognition
- Cardiovascular function
- Muscle function
How it works
- Serves as coenzyme (thiamine pyrophosphate) in carbohydrate metabolism
- Essential for pyruvate dehydrogenase complex function
- Required for transketolase in pentose phosphate pathway
- Supports neurotransmitter synthesis (acetylcholine, GABA)
- Necessary for myelin formation
Dosage
- Typical range
- 1.1 mg daily RDA (women 50+: 1.1 mg); supplements typically 25-100 mg
- Timing
- With meals to enhance absorption
- With food
- Absorption enhanced with food; may cause GI upset on empty stomach
- Duration
- Safe for long-term daily use. Water-soluble excess is excreted in urine.
- Special populations
- Women 50+ have same RDA as younger women. Older adults with poor nutrition, chronic diarrhea, or alcohol use disorder at increased risk of deficiency.
Forms
- thiamine HCl· 70/100
- thiamine mononitrate· 70/100
- thiamine pyrophosphate (TTFD)· 70/100
Safety
Common side effects
- Rare at recommended doses
- Very high doses may cause nausea, headache, or irritability
Contraindications
- None at supplemental doses
Products containing Thiamine (Vitamin B1)
Top-scoring supplements in our catalog that list Thiamine (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
Strong evidence for deficiency correction and energy metabolism support. Well-established essential nutrient with clear clinical evidence for neurological function.
Grade A: Multiple well-designed human trials support the main claims.
Related in Vitamin
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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.