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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.

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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.

How to take it

TimingSplit the glutamine into three doses across the day, as in the trial.
With food?Either way; glutamine dissolves in water and is not irritating.
Worth knowingRead the ingredient list for licorice and confirm it is the deglycyrrhizinated (DGL) form.

Interactions

With medications

  • blood pressure medication and diuretics

    Whole licorice (not the DGL form) raises blood pressure and lowers potassium, working against the drug and adding to potassium loss. check the label for non-DGL licorice and avoid combining

  • digoxin

    Potassium loss from licorice increases the risk of digoxin toxicity. avoid blends containing whole licorice

With other supplements

  • separate glutamine powder

    Blends already supply glutamine, so the totals add up quickly. add up the glutamine across all products you take

Well-established interactions only — this is not a complete list. Always tell your doctor and pharmacist what you take.

Frequently asked questions

Do leaky gut supplements work?

The evidence is limited: "leaky gut" is not a recognised diagnosis, and a meta-analysis of 10 trials found glutamine, the lead ingredient in leaky gut blends, had no overall effect on gut permeability. A signal appeared only above 30 g per day, far more than blends provide.

Does glutamine help IBS?

One placebo-controlled trial found 15 g/day of glutamine, as 5 g three times daily for 8 weeks, reduced symptoms in post-infectious IBS with diarrhoea. It has not been replicated, and most leaky gut blends supply only 2–5 g per serving.

Are leaky gut blends safe?

Glutamine in leaky gut blends should be avoided in cirrhosis or hepatic encephalopathy and used cautiously in kidney disease. Whole liquorice, if not the deglycyrrhizinated form, raises blood pressure and lowers potassium, which matters with diuretics and digoxin.

Should I take a leaky gut formula for ongoing digestive symptoms?

Persistent digestive symptoms deserve a real diagnostic work-up before a leaky gut blend, since the slippery elm, marshmallow and DGL in these products have essentially no controlled trials for gut barrier outcomes.

Scientific references

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