Reading time: 8 minutes | Last updated: October 2026 |

Long COVID gut symptoms can involve much more than digestion. Research has found changes involving the gut microbiome, intestinal barrier, immune signalling and autonomic nervous system after COVID. These may contribute to digestive symptoms and potentially to wider symptoms such as fatigue and brain fog, although the importance of each mechanism probably varies between people.

The gut appears to be an important part of the Long COVID picture. It is not established as the cause of Long COVID, and not everyone with the condition has the same gut abnormalities.

Table of Contents

Key Facts

Studies have found changes in the gut microbiome in some people with Long COVID.
Researchers are investigating altered intestinal permeability, sometimes called “leaky gut”, and microbial translocation.
Gut and immune function are closely connected, but not every immune abnormality in Long COVID begins in the gut.
Dysautonomia can affect digestion and may contribute to nausea, altered gut motility and worsening after meals.
SIBO and post-infectious IBS may explain gastrointestinal symptoms in some people, but they should not automatically be assumed.
Research into the gut-brain axis is particularly interesting, but gut dysfunction is only one possible contributor to brain fog.
Probiotics, synbiotics and microbiome-targeted treatments are being studied, but there is no established microbiome treatment for Long COVID.

Long COVID gut symptoms are not just digestive problems. They can sit alongside changes involving the gut barrier, microbiome, immune system and autonomic nervous system.

If you’ve reached the point where your stomach seems to hold staff meetings without inviting you, welcome to the club. One day you can eat almost anything; the next your digestive system behaves as though you’ve committed a personal offence by looking at a slice of pizza.

It sounds ridiculous until it starts happening to you.

The gut has become an important focus of Long COVID research because SARS-CoV-2 can affect the gastrointestinal tract and because the gut communicates constantly with the immune and nervous systems. Researchers have found changes in the microbiome, gut barrier and immune signalling in some people after infection.

What we do not know is whether those changes drive Long COVID, result from the wider illness, or — probably in different combinations in different people — do a bit of both.

That distinction matters.

The gut may be an important piece of the Long COVID puzzle. It is not necessarily the whole picture.

The Gut Is One of the Body’s Largest Immune Organs

The gastrointestinal tract contains an enormous concentration of immune tissue. Gut-associated lymphoid tissue, or GALT, is one of the body’s largest immune compartments, constantly helping the immune system decide what is harmless, what is potentially dangerous and when an immune response needs to calm down.

The intestinal lining also expresses ACE2, the receptor SARS-CoV-2 uses to enter cells, and gastrointestinal involvement during COVID is well documented.

Researchers are studying how infection may alter intestinal cells, the microbiome, immune signalling and the gut barrier, and whether some of those changes persist after the acute infection.

This is particularly interesting because Long COVID itself can involve substantial changes in immune function.

But there is an important difference between saying the gut interacts with the immune system and saying Long COVID starts in the gut.

We have evidence for the first.

We do not have evidence that the second is true for everyone.

Gut symptoms therefore may not be an entirely separate problem, but neither should every Long COVID symptom be traced back to the digestive system. Researchers increasingly see the gut, immune system, nervous system and metabolism as interacting parts of a much larger biological picture.

The Gut Barrier and “Leaky Gut”: When the Border Becomes Less Selective

Think of your gut as the body’s customs border.

Every day it has to allow nutrients and other useful molecules into the body while keeping bacteria and potentially harmful substances where they belong.

Under normal conditions, the intestinal barrier is selectively permeable. Proteins including claudins and occludin help form tight junctions between intestinal epithelial cells and regulate what crosses that barrier.

Research following COVID has found evidence of altered intestinal-barrier function and microbial translocation — the movement of microbial products from the gut into the circulation — in some patients.

This is related to what is commonly called “leaky gut”, although researchers generally use terms such as increased intestinal permeability.

Several mechanisms are being investigated, including effects of SARS-CoV-2 on intestinal cells and ACE2 signalling, inflammation and changes in the microbiome.

If the intestinal barrier becomes more permeable, microbial products such as lipopolysaccharides may enter the circulation and potentially contribute to immune activation.

A January 2026 Frontiers in Medicine case report, for example, followed intestinal permeability and fatigue in a patient with Long COVID and found that the two changed together over time.

That is interesting.

But because it was an individual case report, it cannot establish that intestinal permeability causes fatigue across Long COVID. It adds to a wider research question: whether gut-barrier dysfunction and microbial translocation contribute to systemic symptoms in some people.

Researchers are also investigating whether gut dysbiosis and altered intestinal permeability can influence the brain through immune signalling, microbial metabolites and the gut-brain axis.

That is biologically plausible.

It is not the same as saying that the gut and brain are literally “leaking together”, or that intestinal permeability has been established as the cause of Long COVID brain fog.

Dysbiosis: When the Microbiome Changes

A healthy gut contains trillions of bacteria, fungi, viruses and other microorganisms forming an extraordinarily complicated ecosystem.

Dysbiosis describes disruption to that microbial community.

Studies from different countries have reported differences in gut-microbiome composition in people with Long COVID compared with recovered or healthy control groups. Research has identified changes involving microbial diversity and particular organisms, including bacteria involved in producing short-chain fatty acids.

Some studies have reported reduced levels of beneficial species such as Faecalibacterium prausnitzii and Bifidobacterium, alongside changes involving organisms including Ruminococcus gnavus.

Why does that matter?

Faecalibacterium prausnitzii

Faecalibacterium prausnitzii produces butyrate, a short-chain fatty acid involved in supporting cells lining the colon, intestinal-barrier function and immune regulation.

Lower abundance has been reported in Long COVID microbiome research.

That does not mean depletion of one bacterium causes Long COVID. The microbiome functions as an ecosystem, and its composition is affected by diet, medication, antibiotics, geography, age and numerous other factors.

Bifidobacterium

Bifidobacterium species are also involved in producing metabolites that interact with intestinal and immune function.

Again, changes involving these organisms are interesting biomarkers and possible contributors rather than proof of a single causal pathway.

Ruminococcus gnavus

Ruminococcus gnavus has been associated with several inflammatory and metabolic conditions and has also appeared in Long COVID microbiome research.

Its presence does not mean it is causing Long COVID. Researchers are trying to understand whether such microbial patterns contribute to inflammation, reflect the inflammatory environment, or both.

What About the Fungi?

The disruption may not be confined to bacteria.

The fungal community living in the gut — sometimes called the mycobiome — is also being studied after COVID. Research has reported changes involving fungal species, including Candida.

But Candida requires some perspective.

Candida normally exists in or on many healthy people. Changes involving Candida in microbiome research are not the same thing as systemic Candida infection, and finding fungal dysbiosis does not establish that Candida is causing someone’s fatigue, bloating, food reactions or Long COVID.

This distinction gets lost remarkably quickly online.

The microbiome may be disrupted.

That does not mean your body has been taken over by fungus.

What About the Mouse Studies?

One particularly interesting line of research has transplanted gut microbiota associated with post-COVID conditions into experimental animals.

Some animal studies have found that transferring altered microbiota can produce biological or behavioural changes in the recipient animals.

This strengthens the case that the microbiome could potentially contribute to disease processes rather than simply being an incidental finding.

But mice are not people with Long COVID.

Animal experiments can provide mechanistic evidence and help researchers decide what to investigate next. They cannot establish that gut dysbiosis is the causal driver of symptoms in humans.

That requires human clinical evidence.

SIBO: When Bacteria Grow Where They Should Not

Small intestinal bacterial overgrowth, or SIBO, occurs when excessive numbers or altered populations of bacteria are present in the small intestine.

It can cause bloating, gas, abdominal distension and altered bowel habits, often becoming particularly noticeable after eating.

Could Long COVID increase susceptibility to SIBO in some people?

Possibly.

One reason is gut motility.

The autonomic and enteric nervous systems help coordinate movement through the digestive tract, including the migrating motor complex that helps clear material through the small intestine between meals.

Because dysautonomia can occur in Long COVID, impaired gut motility is one possible route through which SIBO could become more likely in some people.

But SIBO should not become another catch-all Long COVID diagnosis.

Bloating, diarrhoea, constipation and abdominal discomfort have many possible causes.

SIBO is commonly investigated using hydrogen and methane breath testing, although breath tests themselves have limitations. Treatment depends on the individual clinical situation and sometimes includes antibiotics such as rifaximin.

If you have persistent bloating, distension or other significant gastrointestinal symptoms, it is worth discussing them with your GP or gastroenterology team rather than assuming that SIBO is responsible.

IBS Overlap: Similar Symptoms, Complicated Origins

Post-infectious IBS is not new.

Persistent disorders of gut-brain interaction can develop following gastrointestinal infections, and research after COVID has added another infection to that conversation.

People may experience cramping, bloating, urgency, constipation, diarrhoea or alternating bowel habits after COVID.

In an individual patient, however, several things could potentially contribute: post-infectious IBS, altered gut motility, microbiome changes, autonomic dysfunction, medication effects, SIBO or an entirely separate gastrointestinal condition.

Standard IBS approaches may help some people. A low-FODMAP diet, for example, can reduce symptoms in certain patients.

But restrictive diets also have disadvantages and are not treatments for Long COVID itself.

If gastrointestinal symptoms began after COVID and persist, it can be useful to discuss the full pattern with a clinician rather than assuming that an IBS label explains everything.

The Autonomic Gut: When Digestion Stops Being Automatic

The gut has its own extensive network of neurons called the enteric nervous system.

It works closely with the autonomic nervous system to regulate gut motility, digestive secretions, blood flow and many of the processes that normally happen without us giving them a second thought.

Researchers are investigating how Long COVID may affect these systems.

For people who also have POTS or orthostatic intolerance, the connection can become particularly noticeable.

Gastroparesis

Gastroparesis is delayed gastric emptying.

Food remains in the stomach longer than expected, potentially causing early fullness, nausea, bloating, vomiting or discomfort after eating.

Gastroparesis is a disorder of gastric motility rather than something that would necessarily be visible on a standard endoscopy, and autonomic dysfunction can be one contributor.

These symptoms have other possible causes too, so diagnosis requires appropriate clinical investigation.

Feeling Worse After Meals

Some people with Long COVID report significant worsening after meals, particularly when orthostatic intolerance or autonomic dysfunction is also present.

Digestion increases blood flow to the gastrointestinal tract. In someone already struggling to maintain circulation while upright, this can potentially make dizziness, weakness, palpitations, fatigue or brain fog more noticeable.

This is one reason people with orthostatic intolerance even without POTS may notice that meals affect how they feel.

It is not the only possible explanation.

Blood-sugar changes, reflux, gastrointestinal disorders and other conditions can produce overlapping symptoms.

Nausea

Nausea can occur with autonomic and gastrointestinal dysfunction, but it has many possible causes and should not automatically be attributed to dysautonomia.

If nausea is persistent, severe, associated with vomiting or weight loss, or significantly interferes with eating, it deserves medical assessment.

Altered Bowel Habits

Constipation, diarrhoea or an unpredictable mixture of both can occur when gut motility changes.

The enteric and autonomic nervous systems are possible contributors, but infections, medication, diet, IBS and other gastrointestinal conditions also need consideration.

Long COVID may complicate digestion.

It does not automatically explain every digestive symptom.

The Gut-Brain, Gut-Lung and Gut-Immune Axes

The gut does not operate in isolation.

It communicates with the brain, immune system and other organs through neural, immune, metabolic and microbial pathways.

These connections are real.

What researchers are still establishing is how important they are in Long COVID.

The Gut-Brain Axis

The gut and brain communicate through the vagus nerve, immune signals, microbial metabolites and other pathways.

Short-chain fatty acids produced by gut bacteria can influence both immune and nervous-system function, while changes in microbiome composition may alter those signals.

These pathways provide biologically plausible ways in which gut dysbiosis could influence neurological or cognitive symptoms.

But we cannot currently say how much microbiome changes contribute to Long COVID brain fog in an individual patient.

The Gut-Lung Axis

Researchers also study interactions between gut microbiota and respiratory immunity — the gut-lung axis.

Experimental studies in animals provide intriguing evidence that altering the gut microbiome can influence inflammatory processes elsewhere in the body, including the lungs.

This is an important research direction.

It does not yet establish that gut dysbiosis explains persistent respiratory symptoms in people with Long COVID.

The Gut-Immune Axis

The gut contains an enormous amount of immune tissue and is in constant conversation with microorganisms living there.

Changes in microbial metabolites, intestinal permeability and bacterial composition could therefore influence immune regulation.

These findings have led researchers to investigate whether disruption of the gut microbiome contributes to some of the immune abnormalities observed in Long COVID.

Again, the direction may go both ways.

Systemic illness can change the gut.

The gut may influence systemic illness.

Biology does not always have the courtesy to provide a one-way arrow.

One Intriguing Gut-Brain Pathway: Tryptophan and Serotonin

In 2023, researchers published an important study in Cell reporting reduced circulating serotonin in a group of people with Long COVID.

They proposed a pathway connecting persistent viral and immune activity, the gut, serotonin and the brain.

The researchers found evidence suggesting that persistent viral material could stimulate type I interferon signalling. This was associated with reduced intestinal absorption of tryptophan, an amino acid involved in serotonin production, alongside other changes affecting serotonin availability.

In experimental models, reduced peripheral serotonin affected signalling through the vagus nerve and hippocampal function. Manipulating parts of this pathway could improve cognitive performance in animals.

It is a fascinating piece of mechanistic research.

It is not evidence that everyone with Long COVID brain fog has serotonin deficiency.

It does not establish that tryptophan supplements or SSRIs treat Long COVID brain fog.

Instead, it provides evidence for one possible biological pathway connecting persistent viral and immune activity with gut-related metabolism, vagus-nerve signalling and cognitive symptoms.

That is significant without needing to make it universal.

What Actually Helps?

At this point you may be wondering whether your gut has quietly resigned from its job altogether.

Thankfully, that’s not usually the case.

The gut ecosystem is adaptable, which is one reason researchers are interested in it as a potential therapeutic target.

The less satisfying answer is that research has not yet produced one proven Long COVID gut protocol.

Probiotics and Synbiotics

Probiotics and synbiotics are being investigated as possible interventions.

Some clinical trials have reported improvements in gastrointestinal and wider symptoms. One randomised placebo-controlled trial of a synbiotic preparation, for example, reported improvement in several post-COVID symptoms.

That is encouraging.

But different studies use different bacterial strains, combinations, doses and treatment periods.

“Probiotics” are not one treatment.

At present there is no particular probiotic or combination established as a treatment for everyone with Long COVID.

If you have significant gastrointestinal symptoms, suspected SIBO or other health conditions, discuss probiotics with your GP or a registered dietitian rather than assuming that more bacteria automatically means better bacteria.

Prebiotics and Dietary Fibre

Prebiotic fibres provide food for certain gut bacteria, and diets containing a variety of fibre-rich plant foods generally support microbial diversity.

Foods containing prebiotic fibres include onions, garlic, leeks, asparagus, legumes and resistant starches.

But tolerance matters.

If you have significant bloating, IBS-type symptoms or suspected SIBO, rapidly increasing fermentable fibre can make symptoms considerably worse.

There is no established Long COVID microbiome diet.

The goal should be adequate, tolerable nutrition rather than attempting to create the theoretically perfect microbiome while becoming afraid of half the supermarket.

Faecal Microbiota Transplantation

Faecal microbiota transplantation, or FMT, transfers processed intestinal microorganisms from a carefully screened donor into another person’s gastrointestinal tract.

FMT is an established treatment for certain medical conditions, particularly recurrent Clostridioides difficile infection.

Researchers are investigating whether microbiome modification could have wider applications, including post-COVID conditions.

Early studies are interesting, but FMT is not an established treatment for Long COVID and should only be undertaken in an appropriate medical or research setting.

If the internet has brought you to instructions for performing a home faecal transplant, this is an excellent moment to close the browser.

Smaller Meals

Some people with autonomic dysfunction or delayed gastric emptying find smaller meals easier to tolerate than large ones.

Large meals can increase the circulatory demands of digestion and may worsen post-meal symptoms in some people with POTS or orthostatic intolerance.

This isn’t a universal Long COVID rule.

If eating is becoming difficult, you are losing weight or your range of tolerated foods is shrinking, getting adequate nutrition matters more than following increasingly complicated dietary rules.

Addressing the Autonomic Component

When POTS or dysautonomia contributes to gastrointestinal symptoms, managing the autonomic component may also help symptoms such as post-meal worsening or problems related to gut motility.

Our guide to dysautonomia in Long COVID explains the wider autonomic picture.

Food Triggers

A simple food-and-symptom diary can sometimes help identify patterns.

The word simple matters.

You do not need a spreadsheet containing 47 columns, atmospheric pressure and the precise emotional state in which you consumed a tomato.

If a pattern repeatedly appears, it may be worth discussing with a clinician or dietitian.

Restrictive elimination diets should ideally have a clear purpose and a plan for reintroducing foods rather than becoming permanent by accident.

What Should I Ask My GP About?

Persistent or significant gastrointestinal symptoms after COVID deserve the same medical assessment they would have deserved before COVID existed.

Depending on your symptoms, that might include discussing whether you need investigation for conditions such as IBS, coeliac disease, inflammatory bowel disease, SIBO, gastroparesis or other gastrointestinal problems.

Seek medical advice particularly if symptoms involve unexplained weight loss, blood in the stool, persistent vomiting, difficulty swallowing, significant nutritional problems or severe or worsening abdominal pain.

Having Long COVID does not prevent you from developing something else.

Sometimes the most useful sentence in Long COVID medicine is still:

“Could this be something else?”

Key Takeaways

The gut is one of the body’s major immune organs and communicates extensively with the nervous and immune systems.
Research has found changes involving the gut microbiome and intestinal barrier in some people with Long COVID.
Gut changes may contribute to wider symptoms, but they have not been established as the cause of Long COVID.
Dysautonomia can affect digestion and may contribute to post-meal worsening and altered gut motility.
SIBO and post-infectious IBS may occur in some people but require appropriate assessment rather than assumption.
Gut-brain research, including work involving serotonin and vagus-nerve signalling, is promising but does not provide one explanation for all brain fog.
Probiotics, synbiotics, diet and FMT are being studied, but there is currently no established microbiome treatment that works for everyone with Long COVID.

The gut is genuinely part of the Long COVID research picture.

Studies increasingly show differences involving the microbiome, intestinal barrier and gut-associated immune pathways in at least some people with the condition.

What the evidence does not support is the idea that gut dysfunction is the single explanation for Long COVID, that Candida is the villain behind everything, or that a particular supplement protocol can reliably reverse what COVID did to a complex biological ecosystem.

The interesting story is not that everything begins in the gut.

It is that the gut, immune system, nervous system and metabolism communicate constantly — and COVID may disturb several of them at once.

That story is more complicated.

It is also much more interesting.

Quick Answers

Why does Long Covid cause gut symptoms?

Because SARS-CoV-2 enters the body through ACE2 receptors densely expressed throughout the gut, directly damaging the gut lining, disrupting the microbiome, and impairing the enteric nervous system that governs digestion. The gut also houses 70% of the immune system, making it a central site of the immune dysregulation that drives Long Covid across all organ systems.

What is leaky gut and does Long Covid cause it?

Leaky gut means increased intestinal permeability the gut barrier is damaged and allows bacterial fragments and inflammatory molecules to cross into the bloodstream. Long Covid directly damages the tight junction proteins that maintain the gut barrier. A January 2026 study directly correlated measured intestinal permeability with fatigue severity in Long Covid, with permeability and fatigue worsening and improving together. Leaky gut in Long Covid is a real, measurable, and clinically relevant phenomenon.

What is dysbiosis and how does it affect the rest of the body?

Dysbiosis means an imbalanced gut microbiome too few beneficial bacteria and too many proinflammatory ones. In Long Covid this specifically means depletion of Faecalibacterium prausnitzii and Bifidobacterium, and enrichment of Ruminococcus gnavus. Less beneficial bacteria means less butyrate production, worse gut barrier integrity, impaired immune regulation, reduced serotonin synthesis, and increased systemic inflammation all of which worsen fatigue, brain fog, mood, and virtually every other Long Covid symptom.

Could I have SIBO from Long Covid?

Possibly, particularly if your main symptoms are rapid bloating after eating, excessive gas, abdominal distension, and altered bowel habits that worsen with carbohydrate-rich foods. Long Covid creates the conditions for SIBO through autonomic dysregulation of gut motility and microbiome disruption. A hydrogen and methane breath test can diagnose it. Discuss this specifically with your GP if the symptom pattern fits.

Why does eating make me feel so much worse?

Two main mechanisms. First, digestion diverts significant blood flow to the gut, which in someone with autonomic dysregulation and low blood volume tips the system into POTS-like symptoms â€” heart rate surges, brain fog, fatigue. Second, if you have gastroparesis from autonomic gut dysfunction, food sits in your stomach longer than it should, causing prolonged nausea, bloating, and discomfort. Smaller, lower-fat meals reduce both effects.

Is my brain fog connected to my gut symptoms?

Very likely yes. The gut-brain axis connects gut microbiome health directly to brain function through short-chain fatty acids, serotonin production, vagus nerve signalling, and inflammatory pathways. Reduced SCFA production from gut dysbiosis also increases blood-brain barrier permeability, allowing inflammatory molecules to enter the brain. In Long Covid, the gut and the brain are leaking together, and gut-directed treatment can improve cognitive symptoms alongside gastrointestinal ones.

Do probiotics help Long Covid gut symptoms?

Early clinical trial data suggests yes, for some patients â€” with improvements in fatigue, gastrointestinal symptoms, brain fog, and sleep reported in studies using probiotics and synbiotics. The evidence is still preliminary and not all probiotic strains are equally effective. Lactobacillus and Bifidobacterium species have the most evidence. If you have SIBO, some probiotics can temporarily worsen symptoms. Discuss with your GP or a registered dietitian before starting.

Can Long COVID cause food intolerances?

Yes. Many people notice that foods they previously tolerated now trigger bloating, nausea, diarrhoea or worsening fatigue. Researchers believe changes to the gut microbiome, increased intestinal permeability and immune activation may contribute to these new sensitivities. Not everyone develops food intolerances, and triggers vary from person to person.

Can gut problems make brain fog worse?

Potentially, yes. The gut and brain communicate continuously through the gut-brain axis. In Long COVID, disruption of the microbiome, increased inflammation and changes to the gut barrier may contribute to neuroinflammation and cognitive symptoms. This is one reason digestive symptoms and brain fog often occur together.

Can gut symptoms improve years after COVID?

Yes. Although recovery varies, research suggests the gut microbiome remains adaptable. Improvements in diet, treatment of conditions such as SIBO, better autonomic management and gradual restoration of the microbiome may help some people experience meaningful improvements over time.

Should everyone with Long COVID take probiotics?

Not necessarily. Some probiotic strains appear promising, but the evidence is still developing and not all products have the same effects. People with SIBO or significant digestive symptoms should speak to their GP or a registered dietitian before starting probiotics, as some strains may temporarily worsen symptoms.

Why do I feel worse after eating?

Digestion naturally redirects blood flow towards the gut. In people with Long COVID, especially those with POTS or autonomic dysfunction, this can temporarily reduce blood flow elsewhere, worsening fatigue, dizziness and brain fog. Delayed stomach emptying and altered gut motility may also contribute.

Medical Disclaimer

This guide is for general informational and educational purposes and does not replace personalised medical advice, diagnosis or treatment.

Long COVID can affect the gastrointestinal system in different ways, but new or worsening gastrointestinal symptoms should not automatically be attributed to Long COVID.

Speak with your GP or an appropriately qualified healthcare professional if symptoms are persistent or significantly affecting your daily life. Seek medical assessment for symptoms such as unexplained weight loss, blood in the stool, persistent vomiting, difficulty swallowing, significant nutritional problems or severe or worsening abdominal pain.

Supplements, probiotics, restrictive diets and other microbiome-targeted interventions can also have adverse effects or interact with medications. Discuss significant dietary changes or supplements with an appropriately qualified healthcare professional, particularly if you have SIBO, IBS or another diagnosed gastrointestinal condition.

References

Lau RI, Su Q, Ng SC. Long COVID and gut microbiome: insights into pathogenesis and therapeutics. Gut Microbes. 2025;17(1):2457495.
https://pmc.ncbi.nlm.nih.gov/articles/PMC11776476/
Microbiome and Long COVID-19: Current Evidence and Insights. International Journal of Molecular Sciences. 2025.
https://pmc.ncbi.nlm.nih.gov/articles/PMC12564589/
Wong AC, Devason AS, Umana IC, et al. Serotonin reduction in post-acute sequelae of viral infection. Cell.2023;186(22):4851–4867.e20.
https://pmc.ncbi.nlm.nih.gov/articles/PMC11227373/
Mechanisms of Gut-Related Viral Persistence in Long COVID.
https://pmc.ncbi.nlm.nih.gov/articles/PMC11360392/
Microbiome dysbiosis in Long COVID: a scoping review of mechanistic insights, symptom associations, and therapeutic targets. 2026.
https://pubmed.ncbi.nlm.nih.gov/42717375/