4 Best Probiotics For Anxiety, According to a Gastroenterologist


Anxiety is a state of unease, worry, or fear characterized by heightened physiological and psychological responses, often triggered by perceived threats or uncertainties. 19.1% of US adults have had an anxiety disorder in the last 365 days according to NIMH.

Probiotics are live microorganisms that, when consumed in adequate amounts, confer health benefits by promoting a balanced and beneficial gut microbiota. Probiotics may help with anxiety according to Psych Central. 

"Psychobiotics" which are probiotics, can modulate the gut-brain axis and influencing behaviors, emotions, and cognitive functions according to a 2022 study authored by P Oroojzadeh.

What Is Anxiety?

Anxiety is a common human emotion characterized by feelings of unease, worry, or fear, which can vary in intensity from mild to severe. It is a natural response to stress and can be triggered by various situations or events. Anxiety disorders are a type of mental health condition that involve repeated episodes of intense anxiety and fear. These disorders may interfere with daily life and require appropriate management and treatment.

Anxiety can manifest with physical symptoms like increased heart rate and muscle tension. The American Psychological Association defines anxiety as an emotion accompanied by worried thoughts and physical changes. Generalized anxiety disorder is a specific type of anxiety that involves persistent feelings of anxiety or dread. Treatment and therapies are available for managing anxiety effectively.

What Is Social Anxiety Disorder?

Social anxiety disorder, also known as social phobia, is a type of anxiety disorder characterized by intense fear and anxiety in social situations, particularly when being scrutinized, judged, or evaluated by others. It can lead to avoidance of social interactions and negatively impact relationships and daily life. Treatment options include psychotherapy and, in some cases, antidepressant medication. Social anxiety disorder is distinguished from everyday nervousness by its significant interference with a person's ability to function in social settings.

What Is Generalized Anxiety Disorder?

Generalized Anxiety Disorder (GAD) is a mental health condition characterized by persistent and excessive worry about various issues and situations that is out of proportion to the impact of the events. Individuals with GAD may experience fatigue, difficulty concentrating, and performance issues in school or work due to their constant feeling of being overwhelmed by anxiety according to a 2022 authored by S Munir. The condition can last for more than 6 months and significantly interfere with daily life. Treatment options and management strategies are available to help individuals cope with the excessive worry and anxiety associated with GAD.

What Is Separation Anxiety Disorder?

Separation Anxiety Disorder (SAD) is a mental health condition characterized by excessive worry, fear, and distress when individuals, especially children, are separated from their family members or close attachment figures. The symptoms of SAD are considered excessive for the individual's developmental age and can significantly interfere with daily life. It is not a normal stage of development and requires attention and appropriate management to address the emotional distress experienced by the affected individual according to a 2022 study authored by J Feriante. Separation anxiety disorder can affect both children and adults, and treatment options are available to help individuals cope with their anxiety and related behaviors when separated from their loved ones or caregivers.

What Is High Functioning Anxiety?

High-functioning anxiety refers to a condition in which individuals experience the symptoms of anxiety, such as persistent feelings of fear, unease, or worry, while still successfully managing all the demands of daily life. It is characterized by individuals who appear to function well in their daily activities despite feeling anxious. High-functioning anxiety is not a defined medical diagnosis but is used by people to describe themselves and their emotional experiences. The term highlights the ability of individuals to excel in work, family life, and other areas while coping with anxiety on a day-to-day basis.

How Does The Gut Affect Mental Health?

4 ways that Gut health can affect mental health include through Dysbiosis, GABA, Serotonin and the Hypothalamic-Pituitary-Adrenal Axis. Gut can affect mental health through the bidirectional communication of the gut-brain axis, where the gut microbiota can influence brain function and behavior, impacting mood, anxiety, and cognitive processes.

1. Dysbiosis Causes Anxiety

Dysbiosis and inflammation in the gut have been linked to causing anxiety and depression according to a 2017 study authored by M Clapp. Dysbiosis and inflammation in the gut are linked to causing anxiety due to the bidirectional communication between the central nervous system and gut microbiota, known as the gut-brain axis. The gut microbiota plays a crucial role in influencing various physiological and biochemical processes in the body, including the production of neurotransmitters and inflammatory compounds.

One of the key mechanisms involved is the production of neurotransmitters in the gut by certain probiotic bacteria or their influence on the body's ability to produce neurotransmitters. Neurotransmitters are chemical messengers that play a significant role in transmitting information within the nervous system. Serotonin, often referred to as the "happy" chemical, is a neurotransmitter that affects mood and is predominantly produced in the gut. GABA (Gamma Aminobutyric Acid) is another neurotransmitter responsible for a state of calm and relaxation. There are 4 ways the gut affects mental health as shown in the graphic below.


2. The Gut Produces GABA

Some species of gut bacteria have the ability to produce gamma-aminobutyric acid according to a 2023 study authored by A Monteagudo-Mera. GABA is synthesized by certain gut bacteria through a pyridoxal-5′-phosphate-dependent glutamate decarboxylase (GAD) enzyme, involving the irreversible α-decarboxylation of l-glutamate and consumption of one proton.

This production of GABA in the gut has been linked to the gut-brain axis, showing potential implications for mental health, as GABA is a neurotransmitter that plays a role in regulating mood and anxiety. Bacteroides species are reported as significant GABA producers in the gut. 

Which Probiotics Increase GABA?

Levilactobacillus brevis LB01 (CGMCC 16921) was found to be the most efficient probiotic strain for gamma aminobutyric acid production in a 2023 study authored by A Monteagudo-Mer. 

3. The Gut Produces Serotonin

The gut plays a crucial role in producing serotonin according to a 2018 study authored by J Appleton. It found that bacterial metabolites, especially short-chain fatty acids (SCFAs) produced by gut bacteria, influence the synthesis of serotonin in the gut. These SCFAs can cross the blood-brain barrier and regulate microglia homoeostasis, which is essential for proper brain development and function.

Serotonin is a neurotransmitter that plays a key role in regulating mood, and its low levels have been linked to the development of anxiety. SCFAs are a type of fatty acid with a relatively small molecular structure, and they are produced by the fermentation of dietary carbohydrates by gut bacteria.

4. Gut-microbiota Can Influences The HPA Axis

Gut microbiota can influence the HPA axis through various mediators that cross the blood-brain barrier, including microbial antigens, cytokines, and prostaglandins according to a 2020 study authored by B Misiak.

Alterations in the gut microbiota and increased intestinal permeability in individuals with severe mental disorders, such as major depression, bipolar disorder, and schizophrenia, may impact the functioning of the hypothalamic-pituitary-adrenal axis.

Certain microbial species can affect corticosterone production in the ileum, potentially influencing the activity of the HPA axis. Some metabolites released by certain gut microbes, like short-chain fatty acids, may have a protective effect by attenuating the HPA axis response.

The HPA axis, or hypothalamic-pituitary-adrenal axis, is a complex neuroendocrine system that plays a key role in regulating the body's response to stress and maintaining physiological balance.

Do Probiotics Help With Anxiety?

Yes, probiotics do help those with an anxiety disorder diagnosis and alleviate depressive symptoms in patients with a depression diagnosis or depression scores, according to a 2020 meta-analysis authored by L Chao. The study showed that probiotics can significantly reduce the depression scale for patients with anxiety and depression, as well as healthy participants under stress.

Do Probiotics Make Anxiety Worse?

Probiotics do not make anxiety worse according to current research. To avoid any side effects when taking probiotics for anxiety it's best to start slowly with a lower CFU count and increase it over-time. Probiotic side effects are usually mild and may include gastrointestinal discomfort, bloating, or gas.

4 Best Probiotics For Anxiety


Best Anxiety Probiotic Brand Overall

Alicia's Naturals Flowflora,

40-Billion CFU,

Anxiety Studied Probiotic Strains,

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The 4 best probiotics for anxiety are Lactobacillus plantarum, Lactobacillus paracasei, Lactobacillus acidophilus and Bifidobacterium longum 1714.

  1. 1
    Lactobacillus plantarum: A 2016 study authored by DJ Davis, found supplementation with this probiotic led to a reduction in anxiety-related behavior in adult zebrafish. The probiotic treatment also brought about positive changes in the gut microbiota, enriching certain metabolic pathways and protecting against stress-induced dysbiosis of the GM. The probiotic resulted in alterations in GABAergic and serotonergic signaling in the brain, suggesting a potential link between the gut microbiota and the central nervous system.
  2. 2
    Lactobacillus paracasei: A 2021 study authored by C Karen, found supplementation with this probiotic had a significant beneficial effect on anxiety-like behavior induced by early life stressful experiences in rats. The probiotic treatment also helped in normalizing the levels of stress hormones, neurotransmitters, and glutamate receptors in the stressed rats, which were otherwise altered due to the early life stress. The probiotic positively influenced the gut microbiota, reducing the impact of early life stress-induced dysbiosis.
  3. 3
    Lactobacillus acidophilus: A 2016 study authored by G Akkasheh, supplementation with this probiotic in patients with major depressive disorder resulted in significant improvements in symptoms of depression. After 8 weeks of probiotic intake, patients showed reduced Beck Depression Inventory scores compared to the placebo group. Probiotic supplementation led to beneficial effects on insulin levels, insulin resistance, high-sensitivity C-reactive protein concentrations, and glutathione concentrations.
  4. 4
    Bifidobacterium longum 1714: A 2016 authored by AP Allen, found this probiotic led to a reduction in the physiological and psychological response to acute stress in healthy human adults. Participants who received the psychobiotic showed lower cortisol output and reduced self-reported anxiety in response to a stress-inducing test. Daily reported stress levels were decreased with the consumption of B. longum 1714. It also had a subtle positive impact on visuospatial memory performance and was associated with enhanced frontal midline electroencephalographic mobility, showing improved cognitive processes.

How Long Does It Take For Probiotics To Help Anxiety?

It takes between 1 and 2 months for probiotics to start working for anxiety according to research. To get optimal results from probiotics for anxiety you should take them first thing in the morning on an empty stomach before eating breakfast.

Can Leaky Gut Cause Anxiety?

Yes, there is a suggested connection between leaky gut and anxiety. If not addressed, this may lead to chronic brain inflammation, which could be associated with symptoms of anxiety according to 2020 study authored by E Won. While more research is needed to fully understand this link, there is growing interest in exploring the gut-brain connection as a potential factor influencing mental health and emotional well-being.

Leaky gut, also known as increased intestinal permeability, is a condition where the intestinal lining becomes more porous, allowing unwanted substances such as bacteria and undigested food particles to pass into the bloodstream.

Can Antibiotics Cause Anxiety?

Antibiotics can have both positive and negative effects on Anxiety according to a 2022 study authored by K Dinan. Some antibiotics may cause psychiatric side effects like depression and anxiety, others have shown potential as antidepressants. Antibiotics can impact mental health by influencing the brain-gut-microbiota axis, which involves the gut microbes interacting with the brain through various pathways.

Antibiotics are medications used to treat bacterial infections by inhibiting the growth or killing bacteria, but they can also disrupt the balance of beneficial and harmful bacteria in the microbiome, leading to potential side effects on gut health and overall microbial diversity.

Can Caffeine Cause Anxiety?

Yes caffeine, at doses equivalent to about 5 cups of coffee, can induce panic attacks in a significant proportion of patients with panic disorder according to a 2022 review authored by L Klevebrant. A panic attack is a sudden and intense episode of overwhelming fear or distress, accompanied by physical symptoms such as rapid heartbeat, shortness of breath, and sweating.

Caffeine is a natural stimulant found in coffee, tea, and various other beverages and products, known for its ability to temporarily increase alertness and reduce fatigue. Caffeine may have implications on gut health and microbial composition due to its interactions with the gut-brain axis according to a 2020 study authored by S González.

Can Pregnancy Cause Anxiety?

Yes, hormonal changes during pregnancy can affect brain chemicals, leading to increased anxiety according to a 2000 study authored by LL Altshuler. Antenatal anxiety, also known as anxiety during pregnancy, is a common experience that can affect either parent. While anxiety is a natural part of pregnancy, some women may experience clinically elevated anxiety symptoms, which could be a risk factor for earlier births according to a 2012 study authored by. CD Schetter.

Pregnancy is the period during which a fertilized egg grows and develops inside a woman's uterus, leading to the formation of an embryo and eventually a fetus. It is a natural biological process that typically lasts around 40 weeks, starting from the first day of a woman's last menstrual period.

Can Diabetes Cause Anxiety?

Yes, people with diabetes are at an increased risk of experiencing anxiety. A 2016 study authored by SV Bădescu, found that people with type 2 diabetes are 40% more likely to be diagnosed with anxiety compared to those without diabetes. 

Diabetes is a chronic medical condition characterized by elevated blood glucose levels due to either insufficient insulin production or the body's inability to effectively use insulin.


  • Hi Alicia, I ordered your FlowFlora probiotic and just want to let you know it has changed my life. My anxiety is gone and I feel normal again. I take FlowFlora every morning and then meditate for 10 minutes. No caffeine, yoga also if I have time. Flowflora was the catalyst. Thanks for making such an amazing product.

    • Alicia Harper (Nutritionist)

      Hi Jenny, thank you so much for sharing this it has made my day!!! Please email Alicia’s Naturals support so I can send you a free bottle 🙂

      • I have severe aniexty and severe constipation I tried many different probiotic doesn’t help much pls tell me which brand probiotic is the best for aniexty

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