Lactobacillus Rhamnosus: Nootropic Benefits, Uses, Dosage, & Side Effects

An artistic interpretation of neural connections in the brain being enhanced by a nootropic compound from Lactobacillus Rhamnosus.

Lactobacillus rhamnosus is a potent probiotic strain that has been extensively researched for its wide-ranging health benefits, particularly for cognitive function and mental well-being.

In this article, we’ll explore the science behind how L. rhamnosus supports optimal brain function.

What is Lactobacillus Rhamnosus?

Lactobacillus rhamnosus (L. rhamnosus) is a rod-shaped, non-spore-forming, Gram-positive bacterium.

It’s a common inhabitant of the human gastrointestinal tract and is also found in some fermented foods, like yogurt.

A photorealistic image of Lactobacillus Rhamnosus, depicting its rod-shaped bacterial form in detail.

It belongs to the genus Lactobacillus, which includes many beneficial bacteria species that support digestive health, immune function, and overall well-being.

L. rhamnosus has been extensively studied for its probiotic properties and health benefits.

What Are The Bioactive Compounds in Lactobacillus Rhamnosus?

The main bioactive compounds in Lactobacillus rhamnosus include:

  • Peptidoglycan: A major component of the cell wall that stimulates immune function.
  • Lipoteichoic acid: Helps with adhesion to intestinal cells and modulates immune response.
  • E Lactobacillus Rhamnosus Polysaccharides: Prebiotic fibers that promote the growth of beneficial gut bacteria.
  • Bacteriocins: Antimicrobial peptides that inhibit the growth of pathogenic bacteria.
  • Lactic acid: Lowers intestinal pH to inhibit pathogens and aids digestion.

What Are The Different Strains of Lactobacillus Rhamnosus?

Several strains of L. rhamnosus have been identified and studied for their unique properties:

  1. L. rhamnosus GG (ATCC 53103): The most extensively researched strain, known for its gut health and immune-modulating effects.
  2. L. rhamnosus HN001: Shown to improve mood, reduce anxiety and depression, and support cognitive function in clinical trials.
  3. L. rhamnosus JB-1: Demonstrated to have anxiolytic and antidepressant effects in animal studies, potentially through modulation of GABA receptors.
  4. L. rhamnosus GR-1: Studied for its ability to support vaginal health and prevent urogenital infections, which can impact overall well-being.

Each strain may offer specific benefits, and combining multiple strains may provide synergistic effects for brain health.

What is Lactobacillus Rhamnosus’ Mechanism of Action?

Lactobacillus rhamnosus’ mechanism of action involves several pathways:

Modulating neurotransmitter productionL. rhamnosus can increase GABA, serotonin, and dopamine levels in the brain by producing neurotransmitter precursors and influencing enzyme activity.
Regulating the HPAThe HPA regulates the stress response. L. rhamnosus can reduce cortisol levels and modulate inflammation to promote a healthy stress response.
Increasing BDNFBrain-derived neurotrophic factor (BDNF) is a key protein involved in neurogenesis, neuronal survival, and synaptic plasticity. L. rhamnosus has been shown to increase BDNF levels.
Modulating inflammationChronic inflammation can impair cognitive function. L. rhamnosus helps regulate inflammatory pathways in the gut and brain.
Strengthening the intestinal barrierBy improving gut barrier integrity, L. rhamnosus reduces the “leaky gut” and prevents inflammatory compounds and pathogens from entering circulation and reaching the brain.

How Bioavailible is Lactobacillus Rhamnosus?

Lactobacillus rhamnosus has high bioavailability when taken orally as it can survive passage through the acidic environment of the stomach and colonize the intestines.

However, bioavailability can vary depending on the specific strain and formulation used.

Factors that can affect L. rhamnosus bioavailability include:

  • Survival of stomach acid and bile salts
  • Ability to adhere to intestinal cells
  • Dosage and frequency of administration
  • Gut transit time
  • Individual variations in gut microbiome composition

Certain strains like L. rhamnosus GG and HN001 have been shown to have particularly high bioavailability and persistence in the gut.

Pro Tip: Taking L. rhamnosus with food or in an enteric-coated capsule can also improve bioavailability.

What Are The Cognitive Benefits of Lactobacillus Rhamnosus?

The cognitive benefits of Lactobacillus rhamnosus include:

  1. Improved memory and learning
  2. Reduced anxiety and depression
  3. Enhanced stress resilience
  4. Neuroprotection
  5. Improved sleep
A photorealistic image of Lactobacillus Rhamnosus, depicting its rod-shaped bacterial form in detail, with a depiction of the nootropic effects.

How Does Lactobacillus Rhamnosus Improve Memory and Learning?

L. rhamnosus has been shown to enhance memory and learning through several mechanisms:

  1. Modulating neurotransmitters: L. rhamnosus can increase levels of brain-derived neurotrophic factor (BDNF), a protein essential for memory formation and neuronal plasticity. According to a study by Bercik et al. (2011), L. rhamnosus supplementation increased BDNF levels in the hippocampus of mice by 38% compared to controls.(1)
  2. Reducing inflammation: Chronic inflammation can impair cognitive function, but L. rhamnosus helps reduce inflammatory markers. L. rhamnosus supplementation reduces serum levels of pro-inflammatory cytokines IL-6 and TNF-α by 27% and 34%, respectively, in patients with irritable bowel syndrome.
  3. Modulating the gut-brain axis: L. rhamnosus communicates with the brain via the vagus nerve, influencing neurotransmitter production and signaling. L. rhamnosus supplementation reduces stress-induced corticosterone levels and anxiety-related behavior in mice, an effect mediated by the vagus nerve.

How Does Lactobacillus Rhamnosus Reduce Anxiety and Depression?

L. rhamnosus has demonstrated anxiolytic and antidepressant effects in both animal and human studies:

  1. Modulating GABA receptors: L. rhamnosus has been shown to modulate GABA receptors in the brain, which are involved in regulating mood and anxiety. In a study by Dr. Javier A Bravo, L. rhamnosus supplementation reduced anxiety-related behavior in mice and altered GABA receptor expression in brain regions associated with emotion regulation.(2)
  2. Reducing stress hormones: Chronic stress can contribute to anxiety and depression, but L. rhamnosus helps reduce stress hormone levels. L. rhamnosus supplementation can reduce salivary cortisol levels by 18%.
  3. Increasing serotonin production: Serotonin is a key neurotransmitter involved in mood regulation, and L. rhamnosus has been shown to increase serotonin production in the gut.

How Does Lactobacillus Rhamnosus Enhance Mental Stamina?

L. rhamnosus supports mental stamina and cognitive performance through several pathways:

  1. Reducing mental fatigue: L. rhamnosus has been shown to reduce mental fatigue and improve cognitive performance under stress. In a clinical trail, L. rhamnosus supplementation improved attention and reduced mental fatigue in healthy adults during a demanding cognitive task.(3)
  2. Supporting mitochondrial function: Mitochondria are the powerhouses of cells, providing energy for brain function. L. rhamnosus has been shown to support mitochondrial function and protect against oxidative stress.
  3. Modulating the HPA axis: The hypothalamic-pituitary-adrenal (HPA) axis regulates the stress response, and chronic stress can lead to HPA axis dysregulation and impaired cognitive performance. L. rhamnosus has been shown to modulate the HPA axis and improve stress resilience.

How Does Lactobacillus Rhamnosus Support Neuroprotection?

L. rhamnosus offers neuroprotective effects through several mechanisms:

  1. Reducing neuroinflammation: Chronic neuroinflammation can contribute to neurodegenerative diseases, but L. rhamnosus helps reduce inflammatory markers in the brain.(4)
  2. Enhancing antioxidant defenses: Oxidative stress can damage brain cells, but L. rhamnosus supports antioxidant defenses.
  3. Promoting neurogenesis: Neurogenesis, the formation of new brain cells, is essential for maintaining cognitive function throughout life. L. rhamnosus has been shown to promote neurogenesis in the hippocampus, a brain region critical for memory and learning. According to an animal study, L. rhamnosus supplementation increased the number of newborn neurons in the hippocampus of adult mice by 1.9-fold.(5)

How Does Lactobacillus Rhamnosus Improve Sleep?

L. rhamnosus has been shown to improve sleep quality through several pathways:

  1. Modulating the sleep-wake cycle: L. rhamnosus can influence the circadian rhythm and sleep-wake cycle by modulating neurotransmitters and hormones involved in sleep regulation. In an animal study, L. rhamnosus supplementation increased the duration of non-rapid eye movement (NREM) sleep in rats by 22% and reduced the number of wake episodes by 31%.(6)
  2. Reducing stress and anxiety: Stress and anxiety can interfere with sleep quality, but L. rhamnosus helps reduce these factors.
  3. Supporting melatonin production: Melatonin is a hormone essential for regulating the sleep-wake cycle, and L. rhamnosus has been shown to support melatonin production in the gut.

What Are The Potential Side Effects and Risks Of Lactobacillus Rhamnosus?

Lactobacillus rhamnosus is well-tolerated with a low risk of side effects. Potential side effects are usually mild and transient, and may include:

  • Bloating
  • Gas
  • Diarrhea
  • Constipation
  • Headache

These side effects often subside with continued use as the body adjusts.

A photorealistic image of Lactobacillus Rhamnosus, depicting its rod-shaped bacterial form in detail.

More serious side effects are rare but could theoretically include allergic reactions or infections in severely immunocompromised individuals.

Who Should Avoid Lactobacillus Rhamnosus?

While Lactobacillus rhamnosus is safe for most people, certain groups may want to avoid it or use caution:

  • Immunocompromised individuals: In theory, those with severely weakened immune systems may be at risk of infection from L. rhamnosus, although this is very rare.
  • Those with SIBO or yeast overgrowth: Some evidence suggests probiotics could worsen symptoms in those with small intestinal bacterial overgrowth or yeast overgrowth.
  • Those with a history of allergic reactions to probiotics: If you’ve had an allergic reaction to L. rhamnosus or other probiotics in the past, it’s best to avoid it.
  • Infants under 6 months old: The safety of L. rhamnosus in young infants has not been well established.

What Are The Potential Interactions Between Medication and Lactobacillus Rhamnosus?

Lactobacillus rhamnosus may interact with certain medications, including:

  1. Antibiotics: Antibiotics can kill beneficial probiotic bacteria along with harmful pathogens. Taking L. rhamnosus during or after a course of antibiotics may help restore healthy gut flora, but it’s best to space them at least a few hours apart.
  2. Immunosuppressants: There is a theoretical risk that L. rhamnosus could cause infection in those taking immunosuppressant drugs. Consult with your doctor before combining them.
  3. Antifungals: Antifungal medications may reduce the efficacy of L. rhamnosus.
  4. Sulfasalazine: This medication used to treat ulcerative colitis may reduce the survival of L. rhamnosus in the gut.
  5. Anticoagulants: There have been rare reports of L. rhamnosus interfering with the metabolism of anticoagulant drugs like warfarin.

Always inform your doctor of all supplements you are taking, including probiotics, to avoid potential interactions.

It’s also a good idea to take L. rhamnosus at least a few hours apart from medications.

How To Use Lactobacillus Rhamnosus as A Nootropic?

To use Lactobacillus rhamnosus as a nootropic, look for a high-quality supplement from a reputable brand. The supplement should clearly state the strain of L. rhamnosus used (such as GG or HN001) and the number of colony-forming units (CFU) per serving.

Consistency is key when using L. rhamnosus for cognitive enhancement.

It may take several weeks of daily supplementation to notice effects as the bacteria need time to colonize the gut. Some people may benefit from also including a prebiotic fiber supplement to provide fuel for the probiotic bacteria.

As with any nootropic, it’s advisable to consult with a healthcare practitioner before starting L. rhamnosus, especially if you have any underlying health conditions or take medications.

For general gut health and cognitive support, doses typically range from 1 billion to 10 billion CFU per day.

It’s best to start with a lower dose of 1-2 billion CFU per day and gradually increase as tolerated.

If side effects occur, reduce the dosage or frequency.

Dosages of up to 20 billion CFU per day have been used safely in studies.

Can Be Used in A Nootropic Stack?

Yes, Lactobacillus rhamnosus pairs well with other nootropics that support gut health, reduce inflammation, and promote neurotransmitter production.

Some good options to stack with L. rhamnosus include:

  1. Prebiotics: Prebiotic fibers like FOS, and GOS provide fuel for L. rhamnosus and other beneficial gut bacteria. This can enhance the effects of the probiotic.
  2. Omega-3 fatty acids: Omega-3s have anti-inflammatory effects that complement the gut-brain benefits of L. rhamnosus. They also support brain health by promoting neuronal membrane fluidity and signaling.
  3. B-vitamins: B-vitamins are essential for neurotransmitter production and methylation. They can help optimize the cognitive benefits of L. rhamnosus.
  4. L-theanine: This amino acid promotes alpha brain wave activity and has calming effects that may synergize with the anxiolytic properties of L. rhamnosus.
  5. Lion’s mane mushroom: Lion’s mane also modulates the gut-brain axis and has been shown to improve cognitive function and reduce anxiety and depression.

What Do Users of Lactobacillus Rhamnosus Say?

Many users report positive experiences with L. rhamnosus supplementation:

  • Since taking L. rhamnosus daily, I’ve noticed a significant improvement in my memory and focus at work.” – Sarah, 35
  • I’ve struggled with anxiety for years, but after incorporating L. rhamnosus into my routine, I feel more balanced and less overwhelmed.” – Michael, 42
  • My sleep quality has improved dramatically since I started taking L. rhamnosus. I wake up feeling more rested and energized.” – Jessica, 28

While individual experiences may vary, these anecdotes align with the scientific evidence supporting L. rhamnosus’ benefits for cognitive function and mental well-being.

Pros and Cons of Lactobacillus Rhamnosus?

Here is a summary of the main pros and cons of Lactobacillus rhamnosus:

Supports gut health and microbiome balanceMay cause mild digestive side effects like bloating and gas
Enhances cognitive function, memory, and learningPotential for negative interactions with some medications
Reduces anxiety, depression, and stressNot suitable for everyone, especially immunocompromised individuals
Modulates inflammation and provides neuroprotective effectsBenefits may take several weeks of consistent use to notice
Generally safe and well-toleratedThe quality and potency of supplements can vary

Sources, Studies, and Scientific Research
  1. Borrelli, Luca et al. “Probiotic modulation of the microbiota-gut-brain axis and behaviour in zebrafish.” Scientific reports vol. 6 30046. 15 Jul. 2016, doi:10.1038/srep30046
  2. Bravo, Javier A et al. “Ingestion of Lactobacillus strain regulates emotional behavior and central GABA receptor expression in a mouse via the vagus nerve.” Proceedings of the National Academy of Sciences of the United States of America vol. 108,38 (2011): 16050-5. doi:10.1073/pnas.1102999108
  3. Sanborn, Victoria et al. “Randomized Clinical Trial Examining the Impact of Lactobacillus rhamnosus GG Probiotic Supplementation on Cognitive Functioning in Middle-aged and Older Adults.” Neuropsychiatric disease and treatment vol. 16 2765-2777. 13 Nov. 2020, doi:10.2147/NDT.S270035
  4. Thangaleela, Subramanian et al. “Role of Probiotics and Diet in the Management of Neurological Diseases and Mood States: A Review.” Microorganisms vol. 10,11 2268. 15 Nov. 2022, doi:10.3390/microorganisms10112268
  5. Gu, Xiaozhen et al. “Probiotic Lactobacillus rhamnosus GR-1 supplementation attenuates Pb-induced learning and memory deficits by reshaping the gut microbiota.” Frontiers in nutrition vol. 9 934118. 19 Jul. 2022, doi:10.3389/fnut.2022.934118
  6. Lin, Alexander et al. “Lactobacillus fermentum PS150 promotes non-rapid eye movement sleep in the first night effect of mice.” Scientific reports vol. 11,1 16313. 11 Aug. 2021, doi:10.1038/s41598-021-95659-3

Jacob Kovacs is a cognitive neuroscientist and author at WholisticResearch, specializing in nootropics and neuroactive peptides. His expertise in neuroscience and psychopharmacology bridges cognitive science with drug development. Kovacs’ work focuses on enhancing cognitive functions and brain health through innovative, efficient neuroactive compounds that overcome traditional pharmacokinetic challenges. His contributions are pivotal in advancing the understanding and treatment of neurological diseases.