Vitamin B1
Thiamine, a B vitamin
A B vitamin also called thiamine or thiamin, found in foods such as peas, nuts and wholegrain bread. This page covers only studies in people that measured thinking, memory, mood, stress, sleep, energy, tiredness or quality of life, so it is not all the research on vitamin B1. Here is every such study we could find, sorted from each study's summary.
- Found in: peas, nuts, wholegrain bread
- Most tested: 300 mg a day
- Mostly tested in people with a health condition
From every paper to the studies that matter
Most research on vitamin B1 is about deficiency, food or the lab. This page counts only studies that gave vitamin B1 to people and measured thinking, memory, mood, stress, sleep, energy, tiredness or quality of life.
-
1,681 papers mention vitamin B1 and one of these topics.Every record in PubMed, all years
-
383 are about people.The rest: 336 lab and animal studies, 267 reviews, 695 on chemistry, farming and more
-
56 give vitamin B1 on its own.22 more give it in a blend, such as with other vitamins or with vitamin C and hydrocortisone
-
25 are randomised against a placebo.Randomised controlled trials In a randomised controlled trial, people are put into groups by chance, one taking the treatment and one a placebo or other comparison. Chance spreads differences such as age and health evenly, so a difference between the groups is more likely to be down to the treatment., the strongest kind of study
Bar lengths use a square-root scale so the small numbers stay visible.
How much research there is
- 56 studies giving vitamin B1 to people
- 25 of them randomised against a placebo A placebo-controlled trial compares a real treatment with a dummy that looks the same, the placebo. People often feel better when they expect to, so comparing against a placebo shows how much of the change comes from the treatment itself.
- 4,789 people taking part, where studies say
- 29 systematic reviews A systematic review searches for every study on a question in a set, written-down way, judges the quality of each and sums up what they show together. Many include a meta-analysis. The Atlas lists these as pooled reviews. pooling the trials
Studies in people, by year published
Vitamin B1 on its own, in studies that measured thinking, mood, sleep, energy or quality of life.
What the studies looked at
Each study can measure several things. Choose a topic to see its studies in the list below.
Studies in people with a diagnosed condition are counted here and listed with their population. We describe what they measured, not what they might treat. Most studies also report safety; see below.
What was tested, and how much
Vitamin B1 comes in several forms, including thiamine, benfotiamine and sulbutiamine, so milligrams don't compare directly between forms. Many studies don't state a daily dose. Some dots sit far to the right because a few studies gave very large oral doses, and hospital studies gave thiamine by injection or drip, where the dose is not comparable with a tablet.
Daily amount, one dot per study
Studies per extract
Named extracts are the maker's brand. "Not named" means the study didn't say.
All studies in people
Filter the list, then open a study on PubMed. Each row comes from the study's published summary. Most studies are in people with a health condition, and many are small or open-label with no comparison group.
| Study | Who took part | People | Extract and daily dose | Length |
|---|---|---|---|---|
| Adeli 2026RCT, placebo | University students with menstrual distress | 123 | Thiamine | 9 weeks |
| Bermúdez-Sánchez 2025Crossover, placebo | Quiescent IBD patients with chronic fatigue | 40 | Thiamine | 4 weeks |
| Zandifar 2024RCT, placebo | Inpatients with manic bipolar-I disorder on lithium | 66 | Thiamine, 100 mg | 8 weeks |
| Moti 2024RCT, placebo | Infertile women with PCOS | 64 | Thiamine, 300 mg | 4 weeks |
| Bager 2024Crossover, placebo | Primary biliary cholangitis patients with fatigue | 36 | Thiamine | 4 weeks |
| Gutiérrez-Rey 2024Single-arm or open-label | Women with Wernicke after sleeve gastrectomy | 3 | Thiamine | – |
| Bonnet 2023Single-arm or open-label | Alcohol-dependent inpatients in detoxification | 100 | Thiamine, 200 mg | 2 weeks |
| Listabarth 2023Non-randomised controlled | Alcohol use disorder inpatients in withdrawal | 50 | Thiamine, 300 mg | 8 weeks |
| Bager 2023Crossover, placebo | Quiescent IBD patients with chronic fatigue | – | Thiamine | 4 weeks |
| Dingwall 2022RCT, active or other control | Alcohol misuse patients at risk of Wernicke encephalopathy | 520 | Thiamine | – |
| Bager 2022RCT, active or other control | IBD patients with fatigue | – | Thiamine, 300 mg | 12 weeks |
| Measelle 2021RCT, placebo | Breastfed infants of supplemented mothers | 335 | Not named | 22 weeks |
| Nakamura 2021RCT, placebo | Allogeneic stem cell transplant patients | 64 | Thiamine, 600 mg | 1 weeks |
| Bager 2021Crossover, placebo | Quiescent IBD patients with chronic fatigue | 40 | Thiamine | 4 weeks |
| Bhawal 2021RCT, placebo | Mild cognitive impairment or mild Alzheimer's disease | – | Benfotiamine | 52 weeks |
| Lin 2020Non-randomised controlled | Psychiatric inpatients with Caine-positive Wernicke-Korsakoff | 262 | Thiamine, 450 mg | 1 weeks |
| Gibson 2020RCT, placebo | Amnestic MCI or mild Alzheimer's disease | 70 | Benfotiamine | 52 weeks |
| Sevim 2017Single-arm or open-label | Patients with multiple sclerosis and fatigue | 26 | Sulbutiamine, 400 mg | 9 weeks |
| Hum 2017RCT, active or other control | Adults who stutter | 19 | Thiamine | 2 weeks |
| Ghaleiha 2016RCT, placebo | Inpatients with major depressive disorder on SSRI | 51 | Thiamine | 12 weeks |
| Pan 2016Single-arm or open-label | Mild to moderate Alzheimer's patients | 5 | Benfotiamine, 300 mg | 78 weeks |
| Manzardo 2015RCT, placebo | Men with alcohol use disorder | 85 | Benfotiamine, 600 mg | 26 weeks |
| Costantini 2015Single-arm or open-label | Patients with Parkinson disease | 50 | Thiamine, 29 mg | 42 weeks |
| Abdollahifard 2014RCT, placebo | Female students with premenstrual syndrome | 80 | Thiamine | – |
| Costantini 2014Single-arm or open-label | Hashimoto's thyroiditis patients with fatigue | 3 | Thiamine, 600 mg | – |
| Costantini 2014Single-arm or open-label | Post-stroke patients with fatigue | 3 | Thiamine | – |
| Costantini 2013Single-arm or open-label | Multiple sclerosis patients with fatigue | 15 | Thiamine | – |
| Costantini 2013Single-arm or open-label | Patients with ulcerative colitis or Crohn disease and fatigue | 12 | Thiamine | 3 weeks |
| Choi 2013Crossover, placebo | Female university students | 9 | Thiamine tetrahydrofurfuryl disulfide | 4 weeks |
| Costantini 2013Single-arm or open-label | Women with fibromyalgia | 3 | Thiamine | – |
| Ollat 2007RCT, active or other control | Patients with early Alzheimer disease | – | Sulbutiamine | 26 weeks |
| Shah 2003Single-arm or open-label | Patients with infection and asthenia | 1,772 | Sulbutiamine | 2 weeks |
| Linton 2002Single-arm or open-label | Elderly depressed patients receiving ECT | 3 | Thiamine | – |
| Ambrose 2001RCT, active or other control | Alcohol-dependent adults detoxifying | 107 | Thiamine | 0 weeks |
| Hung 2001Single-arm or open-label | Dialysis patients with unexplained encephalopathy | 30 | Thiamine | – |
| Salas-Salvadó 2000Single-arm or open-label | Women with Wernicke's syndrome after bariatric surgery | 2 | Thiamine | – |
| Lôo 2000RCT, placebo | Inpatients with major depressive episode on clomipramine | – | Sulbutiamine, 600 mg | 8 weeks |
| Tiev 1999RCT, placebo | Adults with chronic post-infectious fatigue | 326 | Sulbutiamine | 4 weeks |
| Benton 1997RCT, placebo | Young adult women | 120 | Thiamine, 50 mg | 9 weeks |
| Wilkinson 1997RCT, placebo | Older adults with subclinical thiamine deficiency | 76 | Thiamine, 10 mg | – |
| Easton 1997Crossover, placebo | Abstinent cocaine-dependent patients | 8 | Thiamine, 5,000 mg | 0 weeks |
| Arai 1997Single-arm or open-label | Wernicke's encephalopathy after gastrectomy | 2 | Vitamin B1 | – |
| Suzuki 1996Crossover, placebo | Male athletes with normal or low thiamine | 16 | Thiamine, 100 mg | 0 weeks |
| Mimori 1996Single-arm or open-label | Patients with Alzheimer disease | – | Fursultiamine (TTFD), 100 mg | 12 weeks |
| Bowden 1994RCT, active or other control | Alcohol-dependent adults without overt Wernicke-Korsakoff | – | Thiamine | 0 weeks |
| Meador 1993Crossover, placebo | Healthy young adults given scopolamine | – | Thiamine, 5,000 mg | 0 weeks |
| Meador 1993Other | Patients with Alzheimer-type dementia | – | Thiamine | – |
| Smidt 1991RCT, placebo | Healthy elderly Irish women with marginal deficiency | 80 | Thiamin, 10 mg | 6 weeks |
| Nolan 1991RCT, placebo | Patients with Alzheimer-type dementia | 15 | Thiamine hydrochloride, 3,000 mg | 52 weeks |
| Vischer 1989Non-randomised controlled | Alcohol dependent men in withdrawal | 45 | Thiamin, 300 mg | 2 weeks |
| Blass 1988Crossover, placebo | Patients with probable Alzheimer disease | 11 | Thiamine hydrochloride, 3,000 mg | 13 weeks |
| Meyer 1985Single-arm or open-label | Wernicke-Korsakoff syndrome patients | 19 | Thiamine, 300 mg | 13 weeks |
| Botez 1985Single-arm or open-label | Epileptic women with phenytoin ataxia | 2 | Thiamine | – |
| Kodama 1983Single-arm or open-label | Boy with pyruvate decarboxylase deficiency | 1 | Thiamine hydrochloride | – |
| Lonsdale 1980Single-arm or open-label | Patients with functional symptoms and low transketolase | 20 | Thiamin | – |
| MORITA 1962Other | Workers with fatigue | – | Thiamine tetrahydrofurfuryl disulfide | – |
What's known about safety
-
In trials
A 12-month trial of benfotiamine at 600 mg a day in 57 people with type 2 diabetes found no relevant difference in side effects from placebo. In healthy adults, benfotiamine doses of 150 to 1200 mg were described as safe and well tolerated, with side effects similar to placebo. Allergic reactions to thiamine are rare and are linked mainly to fast intravenous doses.
Ziegler 2026 (BOND trial); Sheng 2021, two phase I trials; Lis 2026, review of thiamine hypersensitivity
-
In the UK
Thiamin hydrochloride, thiamin mononitrate, thiamine monophosphate chloride and thiamine pyrophosphate chloride are on the permitted list for food supplements. We didn't find benfotiamine or sulbutiamine on that list. The NHS says 100 mg or less a day of thiamin supplements is unlikely to cause harm, and that there isn't enough evidence to know the effects of higher daily doses.
Food Supplements Directive 2002/46/EC, Annex II, as retained in UK law (legislation.gov.uk); NHS vitamins and minerals, B vitamins page, Oct 2026
-
Check first
The NHS advises not taking too much of any vitamin supplement, as it might be harmful. Injected thiamine is a hospital treatment, and rare allergic reactions have followed it. Speak to a pharmacist or doctor before taking higher doses, or if you are pregnant, breastfeeding or take regular medicines. The sources we opened don't cover those cases.
NHS vitamins and minerals, B vitamins page; Lis 2026, review; no pregnancy or medicine guidance found, Oct 2026
Where these studies come from
We list every published study of vitamin B1 in people that measured thinking, memory, mood, stress, sleep, energy, tiredness or quality of life. We count thiamine (hydrochloride or mononitrate), benfotiamine, sulbutiamine, fursultiamine and allithiamine, by mouth, injection or drip, including Wernicke's and alcohol settings. Studies that only measure vitamin B1 (blood levels, diet surveys) are left out, as are studies where only the control group got it. Thiamine added to a shared treatment and compared with that treatment alone counts as on its own, while thiamine with vitamin C and hydrocortisone in sepsis counts as in a blend. This first version is built from each study's summary; full-paper checks come next.
-
We search
PubMed, the world's main library of medical research, for every paper on L-theanine.
-
We keep studies in people
Lab and animal work is counted but left out of the list, because it doesn't tell you what happens in people.
-
We note the basics
Who took part, how many, how much and for how long, from each study's published summary. A second check corrects what the first read gets wrong.
-
We read them in full
Results appear once we've read the whole paper and checked every number. The date at the top shows when this entry was last updated.
Download the study list
Every study in people as a spreadsheet, 56 rows, free to reuse with a link back.
Versions
Each update to the data gets a new version number, so you can tell what changed and when.
See every version
1.0 · 24 Oct 2026. First release. Every published study giving vitamin B1 to people that measured thinking, memory, mood, stress, sleep, energy or quality of life is listed from its summary. None is read in full yet.
Related
- What are nootropics? A UK guideWhat nootropics are, which ones have real evidence behind them, what UK law says and how to choose a supplement.
- What causes brain fog, and what helpsBrain fog isn't a diagnosis, but it's real. Here's what it feels like, what usually causes it, what helps clear it and when to see your GP.
