Could Probiotics Help Kids with ADHD? Here’s What the Science Says
- Sara L
- May 11
- 6 min read
We usually think of probiotics as something you take for overall gut health, or as a quick rescue remedy after a course of antibiotics. But what if the bacteria in your child’s digestive system could also affect their brain—and even their ADHD symptoms?
Researchers are increasingly looking at something called the “gut–brain axis,” the two-way communication between our intestines and brain. It turns out the good bacteria living in our gut can produce special chemicals that support attention, impulse control, and mood. Good bacteria also reduce inflammation in the body, which is especially important in ADHD as inflammation is though to play a role in the condition¹.
So where do probiotics come in? These are live bacteria (often Lactobacillus or Bifidobacterium strains) that may help restore balance in the gut environment. Think of your gut as a dense and varied forest. The probiotics come in and essentially seed the soil, ensuring that even more good gut bacteria take hold and flourish in the forest. Several recent studies have explored whether probiotic supplements could support children with ADHD.
The Gut–Brain Axis in ADHD: A New Frontier
Children with ADHD often show signs of something called “gut dysbiosis”—an imbalance in the types and amounts of bacteria living in their intestines. Gut dysbiosis means that there is an overgrowth of 'bad' microbes, like yeast, and too few 'good' bacterial species. Dysbiosis can result in reduced levels of beneficial species like a tyoe of bacteria called Faecalibacterium. This particular bacteria produces things called short-chain fatty acids. These fatty acids are made when the good gut bacteria breakdown fiber in our gut. That is why it is so important for children to eat a diet rich in fiber as this is what feeds the good gut bacteria which then go onto to make these protective fatty acids. These fatty acids are very versatile and helpful in the the body.
Roles these fatty acids play include:
Supporting the immune system
Controlling any inflammation going on (common in ADHD)²
Indirectly control the brain's production of dopamine and serotonin, which are important for attention and mood regulation respectively in ADHD³
Therefore, any gut imbalance may lead to inflammation and brain chemical imbalances in the brain, worsening ADHD symptoms. Probiotics are being investigated as a way to nudge the gut ecosystem back into balance, potentially improving inflammation, cognition, and even behavior in ADHD.
Clinical Trials: What Do the Results Show?
A handful of randomized controlled trials (RCTs) have looked at probiotics in children with ADHD. The results are mixed—but promising.
A small study in Finland found that infants given a specific probiotic (Lactobacillus rhamnosus GG) for six months were much less likely to develop ADHD or autism by age 13. None of the children in the probiotic group developed these conditions, compared to 17% of those in the placebo group⁴.
In Iran, a multispecies probiotic (including L. reuteri and B. bifidum) was given to children already taking ADHD medication. Those in the probiotic group had a greater drop in symptom scores and reported less anxiety. Kids felt better socially, physically and emotionally when taking a probiotic. Inflammation in the blood was also improved and auditory attention and impulse control improved too⁵.
Another trial gave Lactobacillus acidophilus strain to children taking Atomoxetine (a non-stimulant ADHD medication). Over 12 weeks, kids who got the probiotic showed more improvement in both behavior ratings and attention tests⁶.
Some studies didn’t find a strong benefit on ADHD symptoms—but did see gains in things like cognitive performance (attention, impulse control), especially in younger kids.
Importantly, none of these studies reported serious side effects from probiotics.
So How Might Probiotics Help in ADHD?
Researchers are still unpacking exactly how probiotics could influence brain function in ADHD. Here are a few possibilities:
Reducing inflammation: Several trials found that probiotics lowered blood levels of C-reactive protein (CRP), a marker of inflammation that’s often high in ADHD.
Boosting antioxidants: Kids who took probiotics had higher levels of antioxidants. Antioxidants are like the body's fire fighters, protecting brain cells from stress and damage.
Controlling brain chemicals: Gut bacteria can influence how much dopamine, serotonin, and GABA the brain makes at any time. These important chemicals that control attention, mood, and behavior.
Shifting the gut environment: In one trial, the probiotic group showed changes in the make up of gut bacteria that was related to better performance on attention tests.
What Does the Meta-Analysis Say?
A 2024 meta-analysis looked at seven trials involving nearly 400 children and teens with ADHD. It found that trials that used multi-strain probiotics and those that combined probiotics with standard ADHD medications, like stimulants, showed the strongest link toward improvement in ADHD symptoms. These findings weren’t statistically significant, but they do suggest directions for future research of how probiotics could be useful in ADHD.
Probiotic dosing tips:
Start low and increase slowly: Begin with approximately 1-2 billion CFU daily and gradually increase to the target dose over several weeks. Your child's healthcare provider will determine the target dose based on your child's age.
Consider combination with medication: Several trials showed better results when probiotics were used as an adjunct to ADHD medication rather than being use alone. In other words, if a child is already using medication for ADHD, parents should absolutely consider adding a probiotic.
Age considerations: Younger children (under 10 years) may show more benefits from probiotics than older children, as the bacterial 'forests' in their guts are still growing and establishing. So you are able to positively influence the types of beneficial bacteria you introduce into their tummies based on the probiotics you give them, effectively sowing new seeds.
Multi-strain may be better: Consider formulations with multiple complementary bacterial strains rather than single-strain products. Think of this as growing a healthy forest with many different plants, instead of an orchard full of a single type of tree. See image below for example of multi-strain kids probiotics with lots of different bacterial strains.
Consistency matters: Benefits typically take at least 4-12 weeks to emerge, so consistent daily supplementation is important
Side effects to look out for:
Most studies report that probiotics are well-tolerated with few adverse effects.
However, possible side effects may include:
Temporary digestive discomfort
Gas or bloating
Changes in bowel movements
In rare cases, increased hyperactivity (if this occurs, discontinue use)
Medications your child may be taking that probiotics interact with:
Antibiotics: Take probiotics at least 2 hours before or 4–6 hours after antibiotics
Immunosuppressants: Consult with your healthcare provider before combining
Antifungals: May reduce probiotic effectiveness
People who should not take probiotics without first talking to healthcare provider:
Children with compromised immune systems
Children with central venous catheters
Children with critical illness
Children with known allergies to probiotic ingredients (milk, soy, etc.)
So…Should Your Child Try a Probiotic?
The science isn’t definitive yet, but probiotics show some potential as a complementary tool for managing ADHD—especially for kids already taking medication.
They seem to be most effective when:
Contain multiple strains of different beneficial bacteria. The more diverse the 'forest' that is being planted in the gut, the better the outcomes for our bodies.
Given to younger children, who may have a more flexible gut–brain axis.
Used alongside standard medical treatments.
Children with known gastrointestinal issues or symptoms
Children with higher inflammatory markers in their blood.
As always, talk to your child’s doctor before starting any new supplement. Not all probiotics are the same, and the best strains for ADHD are still being identified.
Final Thoughts
We’re still in the early days of understanding how gut health affects the brain—but the connection is real. For some children with ADHD, especially those with digestive issues or inflammation, probiotics may offer a gentle, low-risk way to support brain function in ADHD.
This site is for general informational purposes only and does not constitute the giving of medical advice. The contents do not constitute the practice of medicine, nursing, or other professional health care services. No provider–patient relationship is formed. Please consult with your child's healthcare provider when considering supplementation for children.
¹Systematic review of gut microbiota and attention-deficit hyperactivity disorder (ADHD) - ResearchGate, accessed May 8, 2025, https://www.researchgate.net/publication/349365803_Systematic_review_of_gut_microbiota_and_attention-deficit_hyperactivity_disorder_ADHD
²Therapeutic efficacy of probiotics for symptoms of attention-deficit hyperactivity disorder in children and adolescents: meta-analysis - ResearchGate, accessed May 8, 2025, https://www.researchgate.net/publication/377691055_Therapeutic_efficacy_of_probiotics_for_symptoms_of_attention-deficit_hyperactivity_disorder_in_children_and_adolescents_meta-analysis
³Navigating ADHD: Insights from Gut Microbiome Research - International Probiotics Association, accessed May 8, 2025, https://internationalprobiotics.org/home/navigating-adhd-insights-from-gut-microbiome-research/
⁴A possible link between early probiotic intervention and the risk of neuropsychiatric disorders later in childhood: a randomized trial - Pubmed, accessed May 8, 2025
⁵Effect of probiotics as an adjunctive therapy with Ritalin among ADHD children and adolescents: a triple-blind randomized controlled trial - Pubmed, accessed May 8, 2025
⁶Assessment of probiotic strain Lactobacillus acidophilus LB supplementation as adjunctive management of attention-deficit hyperactivity disorder in children and adolescents: a randomized controlled clinical trial - Pubmed, accessed May 8, 2025 https://pubmed.ncbi.nlm.nih.gov/37946220/
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