Vitamin B2
Riboflavin, a B vitamin
A B vitamin also called riboflavin, found in milk, eggs, mushrooms and fortified cereals. This page covers only studies in people that measured thinking, memory, mood, stress, sleep, energy, tiredness or quality of life, not all research on vitamin B2. Only a few of those give it on its own. Most give it inside a B complex or multivitamin, which this page counts but doesn't list. Here is every one on its own that we could find, sorted from each study's summary.
- Found in: milk, eggs and mushrooms
- Doses from under 1 mg to 400 mg a day
- Few studies give it on its own
From every paper to the studies that matter
Our search looked only at vitamin B2 papers on thinking, mood, sleep and energy, not at all research on the vitamin. Most of those are lab or animal work, or only measure vitamin B2 in the blood or diet. A smaller share gives it to people, and only a handful give it on its own, which is what this page lists.
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1,212 papers on vitamin B2 and thinking, mood, sleep or energy.Every record in PubMed, all years
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101 are about people.The rest: 310 lab and animal studies, 155 reviews, 646 on chemistry, farming and more
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5 give vitamin B2 on its own.50 more give it in a B complex, a multivitamin or another blend
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1 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
- 5 studies giving vitamin B2 on its own to people, on thinking, mood, sleep and energy
- 1 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.
- 286 people taking part, where studies say
- 13 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 B2 on its own, by mouth. A thin entry, so read it as a few examples, not a full picture.
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 B2 is a single compound, so milligrams compare directly from one study to the next. The few doses here range widely, from the small amount in a fortified food or juice to a high daily dose in people with a rare metabolic condition, and some summaries don't give a dose at all. Most of the studies behind this page used a B complex or multivitamin, so their doses aren't shown.
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. Only a few studies give vitamin B2 on its own, and most studies give it in a B complex or multivitamin, which this page counts but doesn't list.
| Study | Who took part | People | Extract and daily dose | Length |
|---|---|---|---|---|
| Lupica 2022Observational | Adults with late-onset MADD | 10 | Riboflavin, 400 mg | – |
| Fouad 2021RCT, active or other control | Fatigued male construction workers | – | Riboflavin-fortified apple juice, 1 mg | 4 weeks |
| Darin 2017Single-arm or open-label | Family with mitochondrial myopathy, two treated | – | Riboflavin | – |
| Jiang 2006RCT, active or other control | Healthy primary school children | 101 | Riboflavin, 1 mg | – |
| Stott 2005RCT, placebo | Elderly with ischemic vascular disease | 185 | Riboflavin, 25 mg | 52 weeks |
What's known about safety
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In trials
We found no safety review of vitamin B2 supplements among the studies on this page, and the six studies that give it on its own are small, so they can't show how common side effects are. MedlinePlus says leftover riboflavin leaves the body in the urine and that there is no known poisoning from it.
MedlinePlus, Riboflavin (vitamin B2); the library's safety list for this entry, Oct 2026
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In the UK
Riboflavin and riboflavin 5'-phosphate sodium are permitted forms in food supplements. The NHS says you should get all the riboflavin you need from a varied diet, and that taking 40 mg or less a day of riboflavin supplements is unlikely to cause any harm. It also says there isn't enough evidence to know the effects of taking high doses each day.
Directive 2002/46/EC Annex II as retained in UK law (legislation.gov.uk); NHS vitamins and minerals, B vitamins and folic acid, Oct 2026
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Check first
Some studies here used far more than 40 mg a day, which is the NHS's figure for supplements unlikely to cause harm. Whether high doses are safe long term hasn't been settled, and we found no UK guidance on use in pregnancy or breastfeeding beyond the NHS's advice not to take too much. Speak to a pharmacist or doctor first if you take medicines, are pregnant or breastfeeding, or have a metabolic condition.
NHS vitamins and minerals, B vitamins and folic acid; no trials or UK interaction guidance found, Oct 2026
Where these studies come from
We list every published study in people that gave riboflavin or riboflavin 5'-phosphate and measured thinking, memory, mood, stress, sleep, energy, tiredness or quality of life, and that is all this page covers. Vitamin B2 added to usual care or a medicine and compared with that care alone counts as on its own. Given with other vitamins, minerals or other actives that the comparison group didn't get, it counts as a blend, which includes B complexes and multivitamins. Studies that only measured it in the blood, diet or genes are left out, as are studies where it was given only to the comparison group. Riboflavin used as a light-activated agent, such as in corneal cross-linking or blood treatment, is left out too. This first version is built from each study's summary; full-paper checks come next.
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We search
PubMed, the world's main library of medical research, for every paper on L-theanine.
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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.
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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.
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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, 5 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 B2 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.
