Energy metabolism support
Essential cofactor for converting carbs to ATP energy
Vitamin B1 (Thiamine)
Essential B vitamin critical for energy metabolism, nerve function, and carbohydrate utilization
Scientific nameThiamine
FormulaC12H17N4OS
Molecular weight265.35 g/mol
CAS59-43-8
80
absorption score
10
safety / 10
8
USD per month
6
documented interactions
Check it against something
Vitamin B1 (Thiamine) with:
- Amylase
- Ashwagandha
- Avocado Oil
- BCAA (Branched-Chain Amino Acids)
- Beetroot Powder
- Beta-Alanine
- Bifidobacterium lactis
- Bifidobacterium longum
- Bovine Collagen
- Caffeine
- Calcium
- Calcium Bone Formula
- Calcium Carbonate
- Casein Protein
- Chicken Collagen
- Choline (Bitartrate)
- Chondroitin Sulfate
- Coconut Oil
- Collagen Peptides
- Comprehensive Immune Support Complex
- Comprehensive Multivitamin-Mineral Complex
- Creatine HCL
- Creatine Monohydrate
- D-Mannose
- DHA
- Electrolyte Blend
- EPA
- Fish Oil (EPA/DHA)
- Folate (5-MTHF)
- Ginger
- Iron Fumarate
- Iron Sulfate
- Joint Mobility Formula
- Keratin
- Krill Oil
- L-Carnitine
- L-Citrulline
- Lactase
- Lactobacillus acidophilus
- Lactobacillus rhamnosus
- Lipase
- Magnesium Citrate
- Magnesium Glycinate
- Magnesium Oxide
- Marine Collagen
- Melatonin
- Modafinil
- Olive Oil Extract
- Omega-3 + Curcumin + Vitamin D Triple Anti-Inflammatory Formula
- Papain
- Protease
- Saccharomyces boulardii
- Turmeric
- Vitamin B12 (Cyanocobalamin)
- Vitamin B12 (Methylcobalamin)
- Vitamin C (Ascorbic Acid)
- Vitamin C (Sodium Ascorbate)
- Vitamin D3
- Whey Protein
- Zinc Gluconate
Nothing found
99
out of 100
Works better together
Compatible. Timing differs, so follow each supplement's own window.
What it does
mechanism and evidence for each claimBrain and cognitive function
Supports mental clarity, memory, and concentration
Nervous system health
Essential for proper nerve signal transmission
Heart muscle function
Supports healthy cardiovascular function
Mood stabilization
May help with anxiety and mood regulation
Others take these for the same thing
Same goal, different mechanism — check any of them against this one
Ashwagandha
Stress management & energy
300-600mg
A
75%
Vitamin B12 (Cyanocobalamin)
Energy & nerve support
250-1000 mcg
A
70%
Coenzyme Q10 (CoQ10)
Heart health & cellular energy
100-200mg
A
10%
Fish Oil (EPA/DHA)
Heart & brain health
1-2g EPA/DHA
A
85%
Phosphorus
Bone health & energy metabolism
700-1250mg
A
80%
Vitamin B3 (Niacinamide)
Energy & skin health (no flush)
100-1000 mg
A
88%
Every pair we checked
12 combinations scored by the engine
Vitamin B1 (Thiamine) + Caffeine
No documented interaction either way
No known interaction
70
Vitamin B1 (Thiamine) + Creatine Monohydrate
No documented interaction either way
No known interaction
70
Vitamin B1 (Thiamine) + Whey Protein
No documented interaction either way
No known interaction
70
Vitamin B1 (Thiamine) + Turmeric
No documented interaction either way
No known interaction
70
Vitamin B1 (Thiamine) + Alpha-Lipoic Acid (ALA)
High ALA doses may reduce thiamine absorption
Needs attention
78
Vitamin B1 (Thiamine) + Vitamin D3
Prevents arterial calcification from vitamin D
Works better together
78
Vitamin B1 (Thiamine) + Lactase
Improved calcium absorption when consuming dairy
Works better together
82
Vitamin B1 (Thiamine) + Bovine Collagen
Essential for collagen synthesis and cross-linking
Works better together
82
Vitamin B1 (Thiamine) + DHA
Prevents oxidation of DHA and enhances stability
Works better together
82
Vitamin B1 (Thiamine) + Fish Oil (EPA/DHA)
Protects fish oil from oxidation
Works better together
90
Vitamin B1 (Thiamine) + Magnesium Oxide
Required for thiamine-dependent enzyme function
Works better together
94
Vitamin B1 (Thiamine) + Calcium Carbonate
Essential for calcium absorption and utilization
Works better together
94
Dosage
Daily25-100 mg
Maintenance25-50 mg
Therapeutic100-500 mg
MaximumNo established upper limit
Deficiency treatment300-500 mg
Before you take it
VeganYes
When to expect it
First Effects1-2 weeks for energy improvements
Peak Benefits4-6 weeks for cognitive and nervous system benefits
Deficiency Development2-4 weeks with inadequate intake
Toxicity OnsetNo known oral toxicity
How to measure it
MarkerErythrocyte transketolase activity (ETKA)
OptimalActivity coefficient <1.15
FrequencyOnly if deficiency suspected or high-risk groups
What people actually reported to the FDA
CAERS, 4 reports naming it as the suspectMost reported effects
Named as the suspect
4 reports
of 24 that mention it at all
Serious outcome
88%
hospitalisation, emergency room or worse
Other Serious or Important Medical Event4
Visited Emergency Room1
Death1
Reports are voluntary and unverified — they record what someone experienced while taking something, not what the compound caused. Counts skew towards products people take a lot of, and a serious outcome is more likely to be reported than a mild one, so these are not rates. How we filter them →
What actually reaches you
The label counts the carrier, your body does not
Absorption
Very high 80 of 100 · best absorbed form of this compound
Delivered daily
50 mg
Cost per 100 mg delivered
$0.53 comparative — uses the absorption score, not a measured percentage
Works better with
+
Magnesium
Required for thiamine-dependent enzyme function
Cofactor for thiamine pyrophosphate enzymes · level A
+
Other B Vitamins
Work together in energy metabolism
Complementary roles in metabolic pathways · level A
+
Alpha Lipoic Acid
Both involved in mitochondrial energy production
Complementary roles in pyruvate metabolism · level BWhat not to take with Vitamin B1 (Thiamine)
!
Alcohol
Severely depletes thiamine and impairs absorption
Interferes with thiamine transport and phosphorylation · major significance
!
Raw Fish Shellfish
Contains thiaminase enzyme that destroys thiamine
Enzymatic breakdown of thiamine · moderate significance
!
Tannins Tea Coffee
May reduce thiamine absorption
Binding and inactivation · mild significanceMedication interactions
Discuss these with a pharmacist before combiningIncreases thiamine excretion
What to do: Consider thiamine supplementation with long-term use
Thiamine may enhance digoxin effectiveness
What to do: Monitor digoxin levels if starting thiamine
Available forms
Thiamine HCl: Least expensive, Most stable, Most research
Thiamine Mononitrate: Better stability, Good absorption, Less hygroscopic
Benfotiamine: Fat-soluble, Higher bioavailability, Better tissue penetration
Sulbutiamine: Crosses blood-brain barrier better, Nootropic effects
Food sources
Sunflower seeds
1.48 mg/100g · 75
Pork
0.98 mg/100g · 80
Nutritional yeast
11 mg/100g · 85
Brown rice
0.4 mg/100g · 70
Green peas
0.27 mg/100g · 75
Too little
- Fatigue and weakness
- Mental confusion and memory problems
- Muscle weakness and pain
- Cardiovascular problems
- Irritability and depression
- Loss of appetite
- Beriberi (severe): heart failure, nerve damage
Too much
- No known oral toxicity
- Rare allergic reactions (mainly injections)
- Mild digestive upset at very high doses
- No upper limit established
- Excess excreted in urine
Who benefits most
heavy-drinkers
Alcohol significantly depletes thiamine stores
100-300 mg daily
athletes-high-carb
Increased carbohydrate metabolism increases thiamine needs
50-100 mg daily
elderly
Reduced absorption and increased requirements
25-100 mg daily
diabetes-patients
May have increased thiamine requirements
100-300 mg daily
chronic-fatigue
Thiamine deficiency can cause persistent fatigue
100-500 mg dailyWhere to buy it
Look for Vitamin B1 (Thiamine) at 25-100 mg per serving. The form that matters here is Thiamine HCl.
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What else affects it
Beyond other supplements
!
Alcohol
Severely depletes thiamine and impairs absorption
Interferes with thiamine transport and phosphorylation
!
Tannins tea coffee
May reduce thiamine absorption
Binding and inactivationHow it works
- Cofactor for pyruvate dehydrogenase complex (glucose metabolism)
- Required for alpha-ketoglutarate dehydrogenase (Krebs cycle)
- Essential for transketolase (pentose phosphate pathway)
- Required for branched-chain amino acid metabolism
- Supports neurotransmitter synthesis
- Critical for nerve membrane function
Key findings
what the evidence supports- Essential for energy metabolism - established biochemistry
- Prevents beriberi and Wernicke-Korsakoff syndrome
- May improve cognitive function in deficient individuals
- Critical for alcoholics to prevent neurological damage
Sources: NIH Examine.com · data reviewed 2026-08-02
Compiled by Denis, who maintains this database and holds no medical qualification — every figure here is sourced or derived, never asserted. How we calculate it →
Common questions
What are the benefits of Vitamin B1 (Thiamine)?
Documented effects: Energy metabolism support; Brain and cognitive function; Nervous system health; Heart muscle function. Essential cofactor for converting carbs to ATP energy
How much Vitamin B1 (Thiamine) should you take per day?
The common daily range is 25-100 mg. By goal — maintenance: 25-50 mg; therapeutic: 100-500 mg; maximum: No established upper limit; deficiency treatment: 300-500 mg.
When is the best time to take Vitamin B1 (Thiamine)?
Morning with food. First effects are typically reported within 1-2 weeks for energy improvements.
What are the side effects of Vitamin B1 (Thiamine)?
At excessive doses: No known oral toxicity, Rare allergic reactions (mainly injections), Mild digestive upset at very high doses, No upper limit established, Excess excreted in urine. Safety rating at normal doses is 10 out of 10.
What should you not take with Vitamin B1 (Thiamine)?
Separate it from Alcohol, Raw Fish Shellfish, Tannins Tea Coffee by two to four hours. Severely depletes thiamine and impairs absorption
Does Vitamin B1 (Thiamine) interact with medications?
Documented interactions with furosemide-loop-diuretics, digoxin. Discuss these with a pharmacist before combining.
How do you know if you need Vitamin B1 (Thiamine)?
The marker is Erythrocyte transketolase activity (ETKA), optimal range Activity coefficient <1.15. Common deficiency signs: Fatigue and weakness, Mental confusion and memory problems, Muscle weakness and pain, Cardiovascular problems.