Walk into any large pharmacy and find the supplement wall. Somewhere between the magnesium and the ashwagandha there will be bottles promising stress support, adrenal support, and, in the more confident cases, something close to adrenal repair. Turn one over and there is a good chance vitamin B5 is on the label, usually at a dose several hundred times larger than anything your dinner provided.
Pantothenic acid, to give it its proper name, is the least famous of the B vitamins. It has no pellagra, no beriberi, no dramatic deficiency disease to make it memorable. It is the B vitamin that never got a headline.
Which is a shame, because what it actually does is remarkable. Your body converts it into coenzyme A, a molecule involved in so many chemical reactions that listing them properly would take longer than either of us has. Among those reactions: producing the energy your brain runs on, building the neurotransmitter you rely on for memory and attention, and manufacturing the stress hormones that carry you through a difficult week.
So the "anti-stress vitamin" nickname is half right. It is just right for reasons the label almost never explains, and wrong in the specific way the label wants you to believe.
The Vitamin Named After "Everywhere"
The name is a clue. Pantothenic acid comes from the Greek pantothen, meaning "from all sides", which is a slightly poetic way of saying you can find this stuff more or less anywhere. Meat, fish, eggs, dairy, mushrooms, avocados, wholegrains, potatoes, seeds, pulses. It turns up in nearly every whole food, in small but useful amounts.
That ubiquity is exactly why B5 gets ignored. Deficiency in the developed world is genuinely rare. The NIH Office of Dietary Supplements notes that a typical mixed diet delivers around 6mg a day, comfortably above the 5mg adequate intake set for adults, and that the only group it flags as facing a real risk are people with a rare inherited condition affecting the PANK2 gene, where the difficulty lies in converting B5 into coenzyme A rather than in getting enough of it in the first place. Everyone else, in theory, is covered.
Rare, though, is not the same as unimportant. Oxygen is not interesting until you cannot get any. And there is a difference between "almost nobody develops the full deficiency syndrome" and "this nutrient has nothing to do with how your brain feels". The story of what B5 becomes inside you is the part worth knowing.
Coenzyme A: The Molecule Your Brain Cannot Work Without
Vitamin B5 is not really the point. It is a delivery mechanism. Once inside your cells, it gets built into coenzyme A, and coenzyme A is one of the busiest molecules in human biology.
Think of it as a molecular porter. Its job is to grab small chemical fragments, mainly two-carbon acetyl groups, and carry them to wherever the cell needs them. Fats, carbohydrates and proteins all get broken down into acetyl groups, and coenzyme A is what picks them up and delivers them into the Krebs cycle, the engine room where your cells turn all of it into usable energy.
No coenzyme A, no delivery. No delivery, no fuel reaching the engine. According to StatPearls, coenzyme A has a hand in hundreds of biochemical reactions, from cell growth to neurotransmitter production.
This matters more for your brain than for almost any other organ. Your brain is about 2% of your body weight and burns roughly a fifth of your daily energy, a point we dug into in our piece on vitamin B3 and brain energy. It has no meaningful fuel reserve and no low-power mode. It needs a constant, uninterrupted supply, and the porter carrying that fuel is built from vitamin B5.
There is a further curiosity here. When researchers mapped where vitamin B5 actually sits in the rodent brain, they found it concentrated in myelinated structures, the fatty insulation wrapped around nerve fibres. Myelin is largely made of lipids, lipids are built using coenzyme A, and the brain appears to keep local B5 stores exactly where that building work happens. It is early research, and it is in rats rather than people, but it hints that the brain treats this vitamin as something worth stockpiling.
The Acetylcholine Connection
Here is where B5 stops being a metabolism story and starts being a mental health one.
Acetylcholine is the neurotransmitter of attention, learning and memory. It is the system that gets targeted by the drugs prescribed for Alzheimer's disease, and the one blunted by medications with anticholinergic effects, which is why some antihistamines leave you feeling as though your thoughts are wading through treacle.
Your body makes acetylcholine by joining choline to an acetyl group. That acetyl group arrives on the back of, you guessed it, coenzyme A. The Linus Pauling Institute at Oregon State University lists acetylcholine among the essential compounds that depend on acetyl-CoA derivatives, alongside cholesterol, steroid hormones and vitamins A and D.
Now for the honest caveat, because this is precisely the point where supplement marketing goes off the rails. The fact that B5 is required to build acetylcholine does not mean extra B5 builds extra acetylcholine. Bodies are not warehouses. Once a pathway has what it needs, additional raw material usually just gets escorted out through your kidneys. The dependency is real. The dose-response fantasy is not.
Where the "Anti-Stress Vitamin" Name Came From (And Whether It Holds Up)
Coenzyme A is also needed to make cholesterol, and cholesterol is the backbone from which your adrenal glands build steroid hormones, cortisol included. Follow that chain backwards and you arrive at a statement that is entirely true: without vitamin B5, you could not manufacture your own stress hormones.
That true statement is where the "anti-stress vitamin" nickname was born, and where the wellness industry took a running jump. The leap goes something like this: B5 supports your adrenal glands, chronic stress exhausts your adrenal glands, therefore B5 fixes your exhausted adrenal glands. It is a tidy story. The middle step is the problem.
"Adrenal fatigue", the idea that prolonged stress wears your adrenals down into a state of underproduction, is not a recognised medical diagnosis. A systematic review published in BMC Endocrine Disorders went through 58 studies looking for evidence of it, found conflicting results, inconsistent methods and unvalidated cortisol testing, and concluded bluntly that adrenal fatigue is still a myth. Real adrenal insufficiency exists, it is serious, and it is diagnosed by a doctor rather than by a questionnaire on a supplement website. If your cortisol really is misbehaving, the useful reading is our guide to lowering cortisol naturally, not a bottle of B5.
Does that mean B vitamins do nothing for stress? Not quite, and this is where it gets interesting. A 90-day randomised controlled trial gave 60 people a high-dose B vitamin complex or a placebo and measured occupational stress. After twelve weeks the supplement group reported significantly lower personal strain and less confusion and dejected mood. Other measures of mood and anxiety did not budge.
That is a modest, believable result, and it pays to be precise about what it shows. It was an entire B complex, not pantothenic acid alone. Nobody can say which ingredient, if any, did the work. What it suggests is that the B vitamins as a family have some relationship with how heavily stress lands on you, which is a far more sober claim than the one on the bottle.
What Running Low Actually Feels Like
Because natural deficiency is so rare, most of what we know about human B5 depletion comes from two unusual sources.
The first is wartime. Prisoners of war during the Second World War developed a strange and miserable symptom: numbness and painful burning in the feet, severe enough to keep them awake. It became known as burning feet syndrome, and it was relieved specifically by pantothenic acid rather than by B vitamins in general. The evidence is observational and eighty years old, but it is the closest thing to a natural experiment anyone has.
The second is a run of experiments from the 1950s that would struggle to pass an ethics committee today. Researchers gave volunteers omega-methyl pantothenic acid, a compound that blocks the vitamin's normal pathway, in some cases alongside a diet stripped of B5, and recorded what followed.
The numbers were tiny and the results were uneven. In one 1959 study, four healthy young men took the antagonist while eating an otherwise normal diet. One developed nothing worse than a mild headache. Another became drowsy, irritable and depressed, with a tremor and persistent nausea. People did not respond in the same way, and that unevenness matters before anyone treats this as a template.
Pooling that decade of work, the NIH summarises human B5 deficiency like this: headache, fatigue, irritability, restlessness, disturbed sleep, numbness and burning in the hands and feet, and gut disturbance with loss of appetite.
Strip out the neurological symptoms and you are left with something that looks uncomfortably like a description of a bad month. That is the quietly important idea here: the machinery of mood is not separate from the machinery of metabolism. When the energy system falters, the first things to go tend to be patience, sleep and clarity of thought.
The necessary caution is that these were engineered conditions, produced in a handful of volunteers using a drug designed specifically to block the vitamin. Nobody arrives there from a slightly beige diet. But it does tell us what this nutrient is quietly holding up when it works: parts of your mental function you never think about until they wobble.
The Brain Bank Clue
The most intriguing recent research on B5 does not come from nutrition trials at all. It comes from donated brain tissue.
A team examining post-mortem brains found that pantothenate levels in Alzheimer's disease were around 60% lower than in matched controls, and that the reduction showed up in all seven brain regions examined, from the hippocampus to the cerebellum. Alongside it, the enzymes that depend on coenzyme A to run the Krebs cycle were consistently reduced too. The authors proposed, carefully, that the failing energy metabolism seen in Alzheimer's may be connected to a shortage of pantothenic acid in the brain itself.
Related findings have since turned up in other conditions. Pantothenate reductions have been reported in Parkinson's disease dementia and in dementia with Lewy bodies, though in both cases only some regions were affected, and not the same ones. Something seems to go awry with brain pantothenate across several neurodegenerative diseases. It does not go awry in the same places, or to the same degree, in each.
Now the part that supplement marketing will inevitably skip. These are small post-mortem studies. Nine brains against nine in the Alzheimer's work. They cannot tell us direction of travel: low brain pantothenate might contribute to the disease, or it might be a consequence of a brain that has been failing for years. And on diet the researchers are careful rather than certain: they judge a dietary shortfall unlikely, given how little B5 an adult needs and how readily an ordinary diet supplies it, but nobody measured what these people actually ate. If something is going wrong here, it looks more like a problem with how the brain acquires or holds onto the vitamin than with how much arrived on the plate. That is a different problem entirely, and not one you can eat your way out of. It is a fascinating thread of research. It is not, yet, advice.
Who Might Genuinely Be Short of Vitamin B5
For most people eating a reasonably varied diet, B5 is not a concern worth carrying around. There are, however, situations where intake or absorption can slip.
One thing to be clear about first: the scale. None of what follows produces the deficiency described above. The recorded cases of that involved people eating almost no B5 at all, or taking a drug to block it. This is the less dramatic end of the scale: drifting below comfortable rather than falling off a cliff.
Severe malnutrition or very restrictive eating patterns are the obvious ones. Heavy alcohol use is another, partly because alcohol tends to displace food and partly because it interferes with how several B vitamins are absorbed and used, something we covered in our look at thiamine and mental health. Conditions that impair absorption, such as inflammatory bowel disease or coeliac disease, can also make a difference.
Then there is the quiet one: a diet built almost entirely from heavily processed food. Which brings us to a problem that needs its own section.
Where to Find It (And the Cooking Problem)
Pantothenic acid is not fragile in the way vitamin C is, but it does not survive industrial processing well. The NIH puts losses from food processing at anywhere between 20% and nearly 80%. The Linus Pauling Institute is more specific, citing losses of up to 55% in wheat and up to 88% in maize during milling. Freezing and canning cause comparable damage. Ordinary home cooking, reassuringly, does not, although like any water-soluble vitamin a portion of it leaches into the cooking water you then pour down the sink.
So the vitamin found in almost every whole food is substantially removed from many of the things that come in packets. If your diet leans heavily on refined grains and long-life convenience food, you may be getting less than the "it is in everything" framing implies. The same broad principle applies to a lot of nutrients, which is why certain dietary patterns leave people foggy and flat without any single deficiency being diagnosable.
The good sources, with figures from the NIH:
- Beef liver, cooked, 3oz (85g): 8.3mg, more than a full day's worth
- Fortified breakfast cereals, those fortified to 100% of the daily value: 5mg
- Shiitake mushrooms, cooked, half a cup: 2.6mg
- Sunflower seeds, quarter cup: 2.4mg
- Chicken breast, roasted, 3oz (85g): 1.3mg
- Tuna, cooked, 3oz (85g): 1.2mg
- Avocado, half: 1.0mg
- Milk, one cup: 0.9mg
- Potato, baked, one medium: 0.7mg
On official targets, the guidance splits by country. The United States sets an adequate intake of 5mg a day for adults, rising to 6mg in pregnancy and 7mg while breastfeeding. The United Kingdom has not set a figure at all: the NHS simply states that you should get all the pantothenic acid you need from a varied diet. Neither position implies the vitamin is unimportant. Both reflect how difficult it is to fall short of it while eating actual food.
Should You Supplement? An Honest Answer
For most people, no, and the reasoning is not complicated.
Walk back down that pharmacy aisle and the pantothenic acid capsules sold for stress or adrenal support tend to run from 100mg to 500mg, somewhere between twenty and a hundred times the adequate intake. There is no good evidence that this does anything useful for mood or stress resilience in someone who is already eating normally. The trial that showed a real effect on occupational strain used a full B complex, and the effect was modest.
Safety is not the main objection. B5 is water soluble and remarkably well tolerated, which is why no upper limit has ever been set. Problems only really appear at doses in the range of 10g a day, where the usual outcome is diarrhoea and stomach upset. The NHS position is that 200mg a day or less is unlikely to cause harm, while noting there is not enough evidence to know what higher doses do long term. Very high doses have been trialled for acne, an entirely separate use case with its own evidence base, and not a reason to take it for your mood.
The more useful objection is opportunity cost. Money spent on a bottle of the nutrient you were least likely to be short of is money not spent on the things that reliably move mental health: sleep, food you actually cook, movement, daylight, and people. B5 sits inside a family, and the family is easier to cover than any single member. The same logic runs through our pieces on riboflavin and niacin: eat varied food, and the B vitamins largely take care of themselves.
There are exceptions. If you are recovering from a period of severe undereating, managing a malabsorption condition, or working through problem drinking, a B complex under medical supervision is a reasonable conversation to have with a doctor. That is repletion, which is a real thing. It is not the same as optimisation, which mostly is not.
What vitamin B5 deserves is not a place in your supplement drawer. It deserves a moment of recognition. Every clear thought you have today will be powered, somewhere down the chain, by a molecule your body built out of a vitamin you have never once worried about. That seems worth knowing, even if the only action it prompts is putting mushrooms in the omelette.
Frequently Asked Questions
What does vitamin B5 do for the brain?
Vitamin B5 is the raw material your body uses to make coenzyme A, a molecule that carries fuel fragments into the reactions that generate cellular energy. Your brain is unusually energy hungry, so it depends heavily on this pathway. Coenzyme A also supplies the acetyl group used to build acetylcholine, the neurotransmitter central to attention, learning and memory.
Can vitamin B5 help with stress or anxiety?
Not in the way supplement labels suggest. B5 is needed to manufacture cortisol and other steroid hormones, which is where the "anti-stress vitamin" name came from, but that is a requirement rather than a boost. "Adrenal fatigue", the concept most B5 stress supplements are sold against, has been reviewed and rejected as a medical diagnosis. Some evidence suggests a full B vitamin complex may modestly reduce the strain of work stress, but that cannot be attributed to B5 alone.
What are the symptoms of vitamin B5 deficiency?
True deficiency is very rare. When it has been produced experimentally, symptoms included headache, fatigue, insomnia, irritability, restlessness, personality changes, gut disturbance, and numbness or burning in the hands and feet. These are non-specific and overlap with many far more common causes, so they are not something to self-diagnose from.
How much vitamin B5 do I need a day?
The United States sets an adequate intake of 5mg a day for adults, 6mg in pregnancy and 7mg while breastfeeding. The United Kingdom has set no specific figure, advising instead that a varied diet supplies enough. A typical mixed diet provides around 6mg daily.
Is it safe to take a vitamin B5 supplement?
It is generally well tolerated and no upper limit has been established. The NHS considers 200mg a day or less unlikely to cause harm, though there is limited evidence on long-term high doses. Doses around 10g a day can cause diarrhoea and stomach upset. The more relevant question is usually whether a supplement is likely to help, and for most people eating normally, it is not.
