Supplement analysis backed by scientific evidence · PT

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Limited evidenceGut health

Leaky Gut Repair Formulas

Blends built around L-glutamine plus demulcents such as slippery elm, marshmallow root, liquorice and zinc carnosine. "Leaky gut" is not a recognised diagnosis, and the human data on the lead ingredient are mostly null at the doses these products use.

Evidence last reviewed: August 2026

What the science says

  • Reducing intestinal permeability Limited evidence

    A meta-analysis of 10 trials with 352 participants found glutamine supplementation had no overall effect on measured gut permeability; a signal appeared only in the subgroup taking more than 30 g per day, far above what typical blends provide.

  • Post-infectious IBS symptoms Limited evidence

    One randomised placebo-controlled trial gave 15 g/day of glutamine to patients with post-infectious IBS and diarrhoea and reported a large reduction in symptom scores. It is a single trial in a narrow population and has not been replicated.

  • The demulcent herbs in the blend Limited evidence

    Slippery elm, marshmallow root and deglycyrrhizinated liquorice have essentially no controlled trials as isolated ingredients for intestinal barrier outcomes; their inclusion rests on traditional use and mechanism.

Dosage & safety

Studied doseThe positive IBS trial used 5 g of L-glutamine three times daily (15 g/day) for 8 weeks. Most commercial blends supply 2–5 g of glutamine per serving, which is below the dose associated with any measured effect.
SafetyGlutamine is well tolerated at these doses but should be avoided in cirrhosis or hepatic encephalopathy, where nitrogen load matters, and used cautiously in kidney disease. Liquorice (not the deglycyrrhizinated form) can raise blood pressure and lower potassium. Persistent digestive symptoms deserve a real diagnostic work-up before a blend.

Scientific references

Where to buy

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