Reviewed and updated: 12 November 2026
The daily vitamins for cognitive function with approved roles in the UK are vitamin B12, thiamin (B1), vitamin B6 and folate, which contribute to normal psychological function, plus DHA, iron, zinc and iodine, which contribute to normal brain or cognitive function. They matter most when your diet is short of them. Below I go through all seven, where to find them in food, who is most likely to need a supplement, and where the much-talked-about lion's mane mushroom fits in.
When people ask me about "brain vitamins", they are usually worried about feeling foggy or forgetful. The honest answer is less exciting than the marketing, but far more useful: cover the basics first.
Daily vitamins for cognitive function: the quick answer
- Psychological function: vitamin B12, thiamin (B1), vitamin B6 and folate.
- Brain and cognitive function: DHA (an omega-3 fat), iron, zinc and iodine.
- Who benefits most: people whose diet leaves a gap, such as vegans (B12, iodine, DHA), people with heavy periods (iron) and those who rarely eat oily fish (DHA).
- One honest caution: memory or concentration changes that worry you deserve a GP appointment, not just a supplement.
Our pick for this guide
Curious about lion's mane alongside your B vitamins?
Each two-tablet serving gives 267mg of 15:1 lion's mane extract (equivalent to 4,000mg of powder, standardised to 50% polysaccharides) with 4.4mg of vitamin B1 and black pepper extract. A food supplement, not a replacement for medical advice.
From £13.99 · 60 tablets (30 days)
How vitamins support normal brain function
Your brain uses around a fifth of your body's energy, and it relies on a steady supply of vitamins and minerals to make that energy and to build the chemical messengers nerve cells use to talk to each other. The B vitamins in particular work as a team in these processes, which a review from Northumbria University's nutrition and brain researchers sets out in detail (Kennedy, 2016). When intake is low, the system does not run as smoothly. When intake is already good, adding more is unlikely to make you sharper.
1. Vitamin B12
Vitamin B12 contributes to normal psychological function and to the normal functioning of the nervous system, as well as to the reduction of tiredness and fatigue. It is found almost only in animal foods and fortified products, so vegans, many vegetarians and some older adults are most likely to be short. Low B12 can show up as tiredness, pins and needles, a sore tongue and memory or concentration problems, which is exactly why a blood test matters. Our vitamin B12 guide covers forms and doses.
2. Thiamin (vitamin B1)
Thiamin contributes to normal psychological function, normal functioning of the nervous system and normal energy-yielding metabolism. Wholegrains, pork, peas, beans, nuts and fortified breakfast cereals are good sources. Thiamin is also the nutrient we pair with lion's mane in our lion's mane tablets with vitamin B1, at 400% of the NRV per daily serving.
3. Vitamin B6 and folate
Vitamin B6 and folate both contribute to normal psychological function, and B6 also contributes to the normal functioning of the nervous system. B6 is in poultry, fish, potatoes, chickpeas and bananas; folate is in leafy greens, beans, peas and fortified cereals. Keep supplemental B6 to no more than 10mg a day unless advised otherwise, as long-term high doses can affect the nerves.
4. DHA (omega-3)
DHA contributes to the maintenance of normal brain function, with the benefit obtained from 250mg of DHA a day. Oily fish such as salmon, mackerel, sardines and trout are the richest source, and the NHS suggests at least one portion a week. If you do not eat fish, an algae-based omega-3 is the plant-based route. Our guide to omega-3 for heart and brain health explains EPA and DHA.
5. Iron
Iron contributes to normal cognitive function, as well as to the reduction of tiredness and fatigue. Women with heavy periods, pregnant women and some people on plant-based diets are most likely to run low. Only take iron if a blood test shows you need it, and keep to 17mg a day from supplements unless your doctor says otherwise.
6. Zinc
Zinc contributes to normal cognitive function and to many other everyday processes. Meat, shellfish, dairy, seeds, nuts and wholegrains are good sources. High doses taken for long periods can lower copper levels, so keep supplemental zinc modest, ideally 25mg a day or less.
7. Iodine
Iodine contributes to normal cognitive function and normal production of thyroid hormones. Dairy, fish and eggs are the main UK sources, so people avoiding dairy and fish may fall short. It is one of the nutrients vegans most often overlook.
A quiet desk, a warm drink and a clear list. My favourite way to start a thinking day. Illustrative image
Where lion's mane fits in
Lion's mane is a shaggy white mushroom that has been eaten and valued in East Asian cooking and traditional practice for generations, and today many people take it as part of a focused daily routine. It is a botanical rather than a vitamin. Research is at an early stage: in a small 2023 pilot trial in healthy young adults at Northumbria University, people completed one attention task faster an hour after a single dose, while most other measures showed no clear difference and the authors called for larger studies (Docherty and colleagues, 2023). I find it a fascinating ingredient, and I am honest that the science is still developing. Our overview of what the research says about lion's mane and the lion's mane dosage guide go into more detail.
How to build a simple daily routine
- Start with food: wholegrains, eggs or dairy, leafy greens, pulses, nuts and seeds, and oily fish once a week.
- Fill the obvious gap: B12 if you are vegan or older, DHA if you never eat fish, iron only if a test shows you are low.
- Take B vitamins with breakfast and omega-3 with a meal that contains some fat.
- Give it time: eight to twelve weeks of daily use before you judge anything.
If you are curious about combining lion's mane with B vitamins, see whether you can take lion's mane with vitamin B.
Signs you might be low
Tiredness, poor concentration, low mood, pins and needles, a sore tongue, pale skin and breathlessness can all point to low B12, folate or iron, but they have many other causes too, from sleep to thyroid problems. A blood test through your GP is the right way to find out.
What to realistically expect
If you were short of one of these nutrients, correcting it supports the normal processes that depend on it, and many people describe feeling more like themselves over a few months. If you were not short, you are unlikely to notice a change. Sleep, regular movement, time outdoors and social contact remain the most powerful everyday supports for a clear head.
A few cautions worth knowing
- See your GP about any new or worsening memory problems, confusion or changes in personality.
- Ask your pharmacist before combining supplements with medicines, especially blood thinners, antiepileptics, thyroid medicines and metformin.
- If you are pregnant or trying to conceive, follow NHS advice on folic acid and avoid high-dose vitamin A.
- Lion's mane is a mushroom; avoid it if you are allergic to mushrooms, and ask your GP before use in pregnancy or breastfeeding.
Frequently asked questions
What is the best vitamin for cognitive function?
There is no single best one. Vitamin B12, B1, B6 and folate contribute to normal psychological function, and DHA, iron, zinc and iodine contribute to normal brain or cognitive function. The right choice is the one your diet is short of.
Can vitamins improve memory?
If you are low in a nutrient such as B12 or iron, correcting it supports normal brain function. If your levels are already fine, extra vitamins are unlikely to change your memory.
Is lion's mane a vitamin?
No. Lion's mane is a mushroom with a long traditional history. Research on it is still at an early stage.
Should vegans take a brain supplement?
Vegans should make sure they get vitamin B12, and it is worth thinking about iodine and an algae-based omega-3 too.
How long do cognitive vitamins take to work?
If you were low, many people notice a difference over several weeks to a few months of daily use.
Can I take B12 and lion's mane together?
Yes, they are commonly taken together. Check the total amounts of any B vitamins across all the products you use.
Browse all our supplement guides or visit the Pure Vitamins UK home page.
Our pick for this guide
Looking for lion's mane with added vitamin B1?
Two tablets a day provide a standardised lion's mane extract with 4.4mg of vitamin B1, which contributes to normal psychological function. Each pouch lasts a month. A food supplement, not a replacement for medical advice.
From £13.99 · 60 tablets (30 days)
Sources
- Kennedy DO. B vitamins and the brain: mechanisms, dose and efficacy, a review. Nutrients. 2016. PMC4772032
- Docherty S, Doughty FL, Smith EF. The acute and chronic effects of lion's mane mushroom supplementation on cognitive function, stress and mood in young adults: a double-blind, parallel groups, pilot study. Nutrients. 2023. PMC10675414
- UK Government. Great Britain nutrition and health claims (NHC) register. gov.uk
- NHS. Vitamins and minerals. nhs.uk
Dr. Miron, Founder of Pure Vitamins UK.
Food supplements should not be used as a substitute for a varied, balanced diet and a healthy lifestyle. This article is for general information and is not medical advice; speak to your GP or pharmacist if you have a health condition, are pregnant or take medication.
