Vitamin B1
Vitamin B1, also called thiamine, in tablets, capsules, liquid drops and as benfotiamine. We explain how these forms differ, which dosage makes sense next to a B complex, and how to take thiamine day to day.Read more →
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Thiamine supplements: forms, dosage and daily use
Vitamin B1 is better known as thiamine. It is water-soluble, so it dissolves in water and your body keeps only a small store. What you do not use leaves in your urine. A steady daily intake therefore matters more than one large dose. Thiamine contributes to normal energy-yielding metabolism, to the normal functioning of the nervous system, to normal psychological function and to the normal function of the heart. In the UK, thiamine is added to bread flour by law, and pork, wholegrains, pulses, nuts and seeds add more. If you would rather cover several nutrients at once, start with the wider B vitamin group.
The form on the label changes what you are buying
Most tablets in this collection use thiamine hydrochloride or thiamine mononitrate. Both give you plain thiamine. Mononitrate is the more stable form in tablets and fortified foods, while hydrochloride dissolves faster. At the strengths sold here, usually 50 mg to 100 mg, the practical difference is small. Benfotiamine works differently: it is a fat-soluble derivative of thiamine, taken up by a different route, and it raises blood thiamine higher than the same amount of plain thiamine. That makes it a specific choice, not a general upgrade. Your body also needs Magnesium to switch thiamine into its active form, so B1 always works inside your whole intake.
- Thiamine mononitrate: stable, the standard in tablets
- Thiamine hydrochloride: dissolves quickly, common in capsules
- Benfotiamine: fat-soluble derivative, higher blood levels
- Liquid thiamine: small doses, easy to adjust
The percentages on B1 labels confuse many buyers. A 100 mg tablet shows roughly 9,000% of the Nutrient Reference Value, simply because that reference sits around 1 mg. The figure says nothing about how good the product is. Read the milligrams and the form, then compare the cost per day.
How we choose the vitamin B1 we stock
We keep this collection deliberately small. Three things decide what goes in: the form, the amount per tablet or capsule, and whether the combination makes sense. We carry plain thiamine around 100 mg, the level the NHS names as unlikely to cause harm from supplements, and benfotiamine for people who specifically want that form. We leave out products that bury a token amount of B1 in a long list of extras, because you cannot tell what you are taking. We buy directly from the brands, our compliance team checks every label, and we test batches ourselves alongside independent labs. Read how we select our brands.
Who a single B1 supplement suits
Most people in the UK get enough thiamine from food, so this is a targeted product rather than a daily default. It makes sense if your diet is low in wholegrains and pulses, if you eat little variety, or if a doctor or dietitian has told you your level is low. If you feel tired without knowing why, a B complex or a daily multivitamin is usually the more logical start, since a shortfall in one single B vitamin is uncommon. Take thiamine in the morning, with or without food. Any change you notice is gradual, so judge after two to three weeks of consistent use.
Frequently asked questions
What is vitamin B1 and what does it do?
Vitamin B1 is the vitamin thiamine, sometimes written thiamin. It was the first B vitamin discovered, hence the number. It is water-soluble, which means it dissolves in water and your body stores very little of it, so you need it regularly from food or a supplement.
Approved statements are limited and specific: thiamine contributes to normal energy-yielding metabolism, to the normal functioning of the nervous system, to normal psychological function and to the normal function of the heart.
Where do I get vitamin B1 from in food?
In the UK, thiamine is added to white and brown bread flour by law, so bread and fortified breakfast cereals already contribute. Beyond that, pork, wholegrains, brown rice, oats, pulses, nuts, seeds and yeast extract are everyday sources.
One practical detail: thiamine leaks into cooking water and breaks down with heat. If you boil vegetables and pour the water away, you lose some. That is one reason diets built on refined, heavily cooked foods deliver less than the label maths suggests.
How much vitamin B1 do adults need each day?
The daily amounts below are the reference intakes the NHS gives for adults. They are small, because the body uses thiamine in modest quantities.
| Group | Thiamin per day |
|---|---|
| Men, 19 to 64 | 1 mg |
| Women, 19 to 64 | 0.8 mg |
Supplements sold in the UK usually contain 50 mg to 100 mg, far above these figures. That is normal for a water-soluble vitamin, but it is worth knowing that the reference intake and the tablet strength answer different questions.
Source: NHS
Should I take vitamin B1 on its own or in a B complex?
A shortage of one single B vitamin on its own is uncommon, because the B vitamins largely come from the same foods. If your diet has been narrow for a while, a B complex covers more ground for a similar price.
A separate B1 product makes sense when you want a specific amount of thiamine, for example alongside a B complex that only carries a few milligrams, or when you have been advised to take more. If your reason is general tiredness, browse supplements for energy first and choose from there.
Which form of vitamin B1 should I choose?
Start with what you want the product to do, then match the form.
| Form | Character | Suits |
|---|---|---|
| Thiamine mononitrate | Stable, tablet standard | Simple daily use |
| Thiamine hydrochloride | Dissolves quickly | Capsules, higher strengths |
| Benfotiamine | Fat-soluble derivative | Those wanting this form |
| Liquid drops | Flexible amounts | Trouble swallowing tablets |
For most people the two plain forms are interchangeable. Benfotiamine costs more and is absorbed differently, so choose it deliberately, not by default.
When is the best time to take thiamine?
Morning, with or without food. Thiamine is water-soluble and does not need dietary fat, so absorption is not the issue. Two practical reasons favour the morning: it fits the part of the day when you are eating and moving most, and some people find B vitamins taken late leave them feeling alert at bedtime.
Consistency beats timing. Taking the same dose at the same moment each day is what keeps your intake steady, since the body clears the excess quickly.
Can you take too much vitamin B1?
Thiamine has a good safety record and no tolerable upper level has been set in the EU, because there is not enough evidence of harm from high intakes to define one. The NHS gives a practical marker instead: taking 100mg or less a day from supplements is unlikely to cause any harm.
That is why we stock around that level rather than the very high strengths you see elsewhere. If you are considering more, or you take diuretics or other regular medication, discuss it with your GP or pharmacist first.
Is a vitamin B1 supplement suitable during pregnancy or breastfeeding?
Thiamine itself is a normal part of the diet, and needs are slightly higher in pregnancy and while breastfeeding. High-strength single-nutrient tablets are a different question: several UK brands state on the label that their 100 mg product is not recommended if you are pregnant or breastfeeding.
Always read the label of the specific product, and choose a supplement designed for pregnancy rather than a high-dose single B vitamin unless your midwife or GP has advised otherwise.
Why do supplements pair thiamine with magnesium?
Thiamine is not active as it arrives. The body converts it into thiamine pyrophosphate, the coenzyme form that actually does the work in energy metabolism, and that conversion step depends on magnesium.
Practically, this means a large B1 dose is not a shortcut if your overall intake is thin. It also explains a product detail worth checking: liquid supplements sometimes list thiamine pyrophosphate on the label, the pre-converted form. It is a legitimate choice, usually dosed in micrograms rather than the milligrams you see on tablets, so compare the numbers carefully.
