Research review
Does digestive enzymes help with ADHD? What the research does and doesn't show
No trial we've found tests a digestive enzyme supplement for ADHD specifically. Most of the search interest behind this topic points to a separate condition, autism, where two small trials of digestive enzymes found mixed results and reviewers rated the evidence insufficient.
No trial we've found tests a digestive enzyme supplement for ADHD. Most of the search interest behind this topic actually points to a different condition, autism, where two small randomized trials tested different digestive enzymes and found mixed results — reviewers rated the evidence insufficient to draw a conclusion either way.
What the evidence doesn't support
It doesn't support digestive enzyme supplements, including DigeZyme, as a treatment for ADHD or for autism. No controlled trial of any digestive enzyme in ADHD specifically turned up in a literature search. The research that does exist was conducted in autism spectrum disorder — a separate diagnosis with its own criteria, not interchangeable with ADHD — and even there, the trials found were small, mixed, and rated as insufficient evidence by the reviewers who assessed them.
What the trials found
A 2017 systematic review, commissioned by the US Agency for Healthcare Research and Quality for the American Academy of Pediatrics, evaluated 19 randomized controlled trials of dietary interventions and nutritional supplements in children with autism spectrum disorder. Two of those trials tested different digestive enzyme products and reported mixed effects on symptom severity; the reviewers rated the strength of that evidence insufficient to draw a conclusion. The same review found omega-3 supplementation didn't affect challenging behaviors, and rated evidence for other supplements (methyl B12, levocarnitine) and for gluten/casein-free diets similarly insufficient. Its overall conclusion: little evidence supports nutritional supplements or dietary therapies for children with autism spectrum disorder.
A broader 2024 review of complementary and alternative approaches used in autism, covering 39 studies published between 2013 and 2023, lists digestive enzymes among the nutraceuticals families commonly try — alongside vitamins, minerals, omega-3s, prebiotics and probiotics. It found the evidence doesn't support some of the most frequently used dietary interventions, such as a gluten-free, casein-free diet, and concluded that targeted nutraceutical supplements, digestive enzymes included, may be of benefit but more conclusive research is still needed before that can be said with confidence.
DigeZyme itself has not been tested in either ADHD or autism. Its one controlled trial enrolled adults with functional dyspepsia — a different, diagnosed digestive condition, and a different population entirely from either topic on this page.
Questions people ask
Do digestive enzymes help with autism?
Two randomized trials of different digestive enzymes in children with autism found mixed effects on symptom severity, and a major systematic review rated that evidence insufficient to draw a conclusion. It doesn't support digestive enzymes as a treatment for autism.
Do digestive enzymes help with ADHD?
No controlled trial we've found tests a digestive enzyme supplement in ADHD specifically. The enzyme research that exists was conducted in autism, a different diagnosis, so there isn't a direct answer for ADHD to report here.
Why do people connect digestive enzymes to autism or ADHD at all?
Digestive enzymes have been studied as one part of broader dietary approaches tried in autism, alongside gluten/casein-free diets and other supplements, based on theories about diet, digestion and behavior. The trials that have tested this directly found mixed, low-certainty results, which is different from those theories being confirmed.
When to talk to a doctor
ADHD and autism are both diagnosed and managed by a doctor or specialist. Digestive enzyme supplements are not a treatment for either condition, and nothing in the research above supports using one as a substitute for an evaluation or the care a doctor or specialist might recommend. If a child or adult is already taking medication for either condition, ask a doctor before adding a supplement.
See what is DigeZyme and digestive enzymes: what the research does and doesn't show for the wider evidence on this ingredient.
Sources
- Evaluation of the Safety and Efficacy of a Multienzyme Complex in Patients with Functional Dyspepsia: A Randomized, Double-Blind, Placebo-Controlled Study A 2018 placebo-controlled trial found that adults with functional dyspepsia who took DigeZyme (150 mg/day) for 60 days scored significantly better on several symptom questionnaires than those given a placebo, with no reported product-related side effects; the trial was run and funded by DigeZyme's own maker.
- Nutritional and Dietary Interventions for Autism Spectrum Disorder: A Systematic Review A 2017 systematic review commissioned by AHRQ for the American Academy of Pediatrics found two randomized trials of different digestive enzymes in children with autism reported mixed effects on symptom severity, and rated the overall evidence for nutritional supplements in autism, digestive enzymes included, insufficient to draw a conclusion.
- Complementary and Alternative Medicine for Autism - A Systematic Review A 2024 systematic review of complementary and alternative approaches to autism lists digestive enzymes among the nutraceuticals people commonly use, and concludes the evidence across this category, including digestive enzymes, isn't yet conclusive.
*These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease.