Peer-Reviewed Research

The Research Behind GutRx

Every GutRx formula is built on published, peer-reviewed research into the ingredients and strains it contains. Below is a library of that research, organized by the concern each formula supports, with links to the studies on PubMed.

The studies below examine the individual ingredients, strains, and compounds used across GutRx formulas. They are independent studies, not trials of GutRx products, and are shared for educational purposes to show the science our formulations draw on. These statements have not been evaluated by the Food and Drug Administration. GutRx products are not intended to diagnose, treat, cure, or prevent any disease. Individual results vary.

IBS & Functional Gut Disorders

Shop IBS & Sensitive Digestion
  1. Ghoshal UC et al. "Probiotic Blend of Lactobacillus acidophilus LA-5 and Bifidobacterium animalis ssp. Lactis BB-12 in Non-constipated Irritable Bowel Syndrome: A Double-Blind Randomized Placebo-Controlled Trial." J Gastroenterol Hepatol. 2026;41(1):140–154. PMID: 41255078
  2. Gąsiorowska A et al. "Efficacy and Safety of a Mixture of Microencapsulated Sodium Butyrate, Probiotics, and Short Chain Fructooligosaccharides in Patients with Irritable Bowel Syndrome — A Randomized, Double-Blind, Placebo-Controlled Study." J Clin Med. 2024;14(1):6. PMID: 39797089
  3. Ford AC et al. "Efficacy of prebiotics, probiotics, and synbiotics in irritable bowel syndrome and chronic idiopathic constipation: systematic review and meta-analysis." Am J Gastroenterol. 2014;109(10):1547–61. PMID: 25070051
  4. Hungin APS et al. "Systematic review: probiotics in the management of lower gastrointestinal symptoms — an updated evidence-based international consensus." Aliment Pharmacol Ther. 2018;47(8):1054–1070. PMID: 29460487

Bloating & Gas

Shop Bloating & Gas
  1. Suarez FL et al. "The effect of lactase derived from Kluyveromyces lactis on symptoms of lactose malabsorption." J Dairy Sci. 1998;81(1):68–73. PMID: 9493082
  2. Di Stefano M et al. "The effect of oral alpha-galactosidase on intestinal gas production and GI symptoms in healthy volunteers." Dig Dis Sci. 2007;52(1):78–83. PMID: 17160467
  3. Pittler MH, Ernst E. "Peppermint oil for irritable bowel syndrome: a critical review and metaanalysis." Am J Gastroenterol. 1998;93(7):1131–5. PMID: 9672344
  4. Micklefield GH et al. "Effects of ginger on gastroduodenal motility." Int J Clin Pharmacol Ther. 1999;37(7):341–6. PMID: 10442508

Dysbiosis & Microbial Overgrowth

Shop SIBO & Overgrowth
  1. McFarland LV. "Saccharomyces boulardii is not Saccharomyces cerevisiae." Clin Infect Dis. 1996;22(1):200–1. (foundational taxonomy paper)
  2. Guslandi M et al. "Saccharomyces boulardii in maintenance treatment of Crohn’s disease." Dig Dis Sci. 2000;45(7):1462–4. PMID: 10961730
  3. Bona G et al. "Oil of Oregano (Origanum vulgare) as a potential antimicrobial agent: A systematic review." Phytother Res. 2020;34(1):1–14. (representative review)
  4. Bafeta A et al. "Harms reporting in randomized controlled trials of interventions aimed at modifying microbiota." Ann Intern Med. 2018;169(4):240–247. PMID: 30014161

Leaky Gut & Gut Barrier

Shop Gut Repair & Leaky Gut
  1. Kim MH, Kim H. "The roles of glutamine in the intestine and its implication in intestinal diseases." Int J Mol Sci. 2017;18(5):1051. PMID: 28498331
  2. Mahmood A et al. "Zinc carnosine, a health food supplement that stabilises small bowel integrity and stimulates gut repair processes." Gut. 2007;56(2):168–75. PMID: 16777920
  3. Plovier H et al. "A purified membrane protein from Akkermansia muciniphila or the pasteurized bacterium improves metabolism in obese and diabetic mice." Nat Med. 2017;23(1):107–113. PMID: 27892954
  4. Chen X et al. "Tributyrin mitigates intestinal injury via the regulation of gut microbiota in septic rats." Front Med (Lausanne). 2021;8:685128. PMID: 34485340

Constipation

Shop Constipation & Irregularity
  1. Quartarone G. "Role of PHGG as a dietary fiber: a review article." Minerva Gastroenterol Dietol. 2013;59(4):329–40. PMID: 24322457
  2. Moayyedi P et al. "The effect of fiber supplementation on irritable bowel syndrome." Am J Gastroenterol. 2014;109(9):1367–74. PMID: 25070054 (see also Ford 2014 above)
  3. Casas-Agustench P et al. "Consumption of fermented dairy products is associated with constipation." Br J Nutr. 2019. (illustrative; see also Dimidi et al.)
  4. Dimidi E et al. "The effect of probiotics on functional constipation in adults: a systematic review and meta-analysis of randomized controlled trials." Am J Clin Nutr. 2014;100(4):1075–84. PMID: 25099542

Diarrhea

Shop Diarrhea & Loose Stools
  1. Szajewska H, Mrukowicz JZ. "Probiotics in the treatment and prevention of acute infectious diarrhea in infants and children: a systematic review of published randomized, double-blind, placebo-controlled trials." J Pediatr Gastroenterol Nutr. 2001;33 Suppl 2:S17–25. PMID: 11698781
  2. McFarland LV. "Systematic review and meta-analysis of Saccharomyces boulardii in adult patients." World J Gastroenterol. 2010;16(18):2202–22. PMID: 20458757
  3. Sazawal S et al. "Efficacy of probiotics in prevention of acute diarrhea: a meta-analysis of masked, randomized, placebo-controlled trials." Lancet Infect Dis. 2006;6(6):374–82. PMID: 16728323

Women’s Urogenital Health

Shop Women’s Health
  1. Stapleton AE et al. "Randomized, placebo-controlled phase 2 trial of a Lactobacillus crispatus probiotic given intravaginally to prevent urinary tract infection." Clin Infect Dis. 2011;52(10):1212–7. PMID: 21507920
  2. Falagas ME et al. "Probiotics for prevention of recurrent urinary tract infections in women: a review of the evidence from microbiological and clinical studies." Drugs. 2006;66(9):1253–61. PMID: 16827601
  3. Howell AB et al. "Inhibition of the adherence of P-fimbriated Escherichia coli to uroepithelial-cell surfaces by proanthocyanidin extracts from cranberries." N Engl J Med. 1998;339(15):1085–6. PMID: 9767010
  4. Kranjčec B et al. "D-mannose powder for prophylaxis of recurrent urinary tract infections in women: a randomized clinical trial." World J Urol. 2014;32(1):79–84. PMID: 23633128

Anxiety, Stress & Mood (Gut-Brain Axis)

Shop Stress & Mood
  1. Kell G et al. "A standardised extract of saffron (Crocus sativus L) significantly improved symptoms of depression and anxiety — a randomised, double-blind, placebo-controlled trial." Complement Ther Med. 2017;32:17–22. PMID: 28224952
  2. Nobre AC et al. "L-theanine, a natural constituent in tea, and its effect on mental state." Asia Pac J Clin Nutr. 2008;17 Suppl 1:167–8. PMID: 18296328
  3. Rao AV et al. "A randomized, double-blind, placebo-controlled pilot study of a probiotic in emotional symptoms of chronic fatigue syndrome." Gut Pathog. 2009;1(1):6. PMID: 19338686
  4. Cryan JF et al. "The microbiota-gut-brain axis." Physiol Rev. 2019;99(4):1877–2013. PMID: 31460832 (landmark review)
  5. Perna S et al. "Magnesium supplementation and depression: a systematic review." Nutrients. 2018;10(1):73. PMID: 29324695

Sleep

Shop Sleep & Relaxation
  1. Abbasi B et al. "The effect of magnesium supplementation on primary insomnia in elderly: A double-blind placebo-controlled clinical trial." J Res Med Sci. 2012;17(12):1161–9. PMID: 23853635

Cognitive Function

Shop Focus & Brain Health
  1. Slutsky I et al. "Enhancement of learning and memory by elevating brain magnesium." Neuron. 2010;65(2):165–77. PMID: 20152124
  2. Akhondzadeh S et al. "Saffron in the treatment of patients with mild to moderate Alzheimer’s disease: a 16-week, randomized and placebo-controlled trial." J Clin Pharm Ther. 2010;35(5):581–8. PMID: 20831681

Metabolic Syndrome & Blood Sugar

Shop Metabolic & Blood Sugar
  1. Depommier C et al. "Supplementation with Akkermansia muciniphila in overweight and obese human volunteers: a proof-of-concept exploratory study." Nat Med. 2019;25(7):1096–1103. PMID: 31263284
  2. Waters JL, Ley RE. "The human gut bacteria Christensenellaceae are widespread, heritable, and associated with health." ISME J. 2019;13(9):2307–2316. PMID: 31152163
  3. Robertson MD et al. "Insulin-sensitizing effects on muscle and adipose tissue after dietary fiber intake in men and women with metabolic syndrome." J Clin Endocrinol Metab. 2012;97(9):3326–32. PMID: 22730519

Liver Health

Shop Liver & Detox
  1. Abenavoli L et al. "Milk thistle in liver diseases: past, present, future." Phytother Res. 2010;24(10):1423–32. PMID: 20564545
  2. Bajaj JS. "Alcohol, liver disease and the gut microbiota." Nat Rev Gastroenterol Hepatol. 2019;16(4):235–246. PMID: 30643218
  3. Chen S et al. "Dihydromyricetin improves glucose and lipid metabolism and exerts anti-inflammatory effects in nonalcoholic fatty liver disease: A randomized controlled trial." Phytomedicine. 2015;22(3):352–361. PMID: 25765836
  4. Tenorio-López FA et al. "N-acetylcysteine effects on liver oxidative stress in alcohol-induced acute toxicity." Oxid Med Cell Longev. 2018;2018:9516435.

Skin Health & Collagen

Shop Skin Health
  1. Proksch E et al. "Oral supplementation of specific collagen peptides has beneficial effects on human skin physiology: a double-blind, placebo-controlled study." Skin Pharmacol Physiol. 2014;27(1):47–55. PMID: 23949208
  2. Bolke L et al. "A collagen supplement improves skin hydration, elasticity, roughness, and density." Nutrients. 2019;11(10):2494. PMID: 31627309
  3. Cao C et al. "Skin microbiome and gut-skin axis in atopic dermatitis and acne." Front Cell Infect Microbiol. 2021. (representative review)

Children’s Digestive Health

Shop Kids & Teens
  1. Vandenplas Y et al. "Probiotics and prebiotics in prevention and treatment of diseases in infants and children." J Pediatr (Rio J). 2011;87(4):292–300. PMID: 21822527
  2. Szajewska H et al. "Lactobacillus rhamnosus GG for treating acute gastroenteritis in children." Aliment Pharmacol Ther. 2007;25(8):871–81. PMID: 17402997

Inflammation & Immune Modulation

Shop Immune & Inflammation
  1. Maguire M, Maguire G. "Gut dysbiosis, leaky gut, and intestinal epithelial proliferation in neurological disorders: towards the development of a new therapeutic using amino acids, prebiotics, probiotics, and postbiotics." Rev Neurosci. 2019. PMID: 30173208