When people talk about a “leaky gut,” they are generally referring to increased intestinal permeability—a situation in which the intestinal barrier is not functioning as effectively as it should.

Your intestinal lining is designed to do two jobs at the same time: absorb nutrients from the foods you eat while helping keep unwanted substances inside the digestive tract. The cells lining the intestine are connected by structures known as tight junctions, which help regulate what passes through the intestinal barrier.

Factors such as inflammation, gastrointestinal infections, certain medications, alcohol, dietary factors, and physiological stress may affect intestinal barrier function.

Supporting the intestinal lining therefore isn't simply about digestion. A healthy gut barrier is an important part of normal immune and gastrointestinal function.

Our gut-support protocol focuses on five nutritional compounds that may help support the intestinal lining and gastrointestinal environment.

1. L-Glutamine — 5 Grams Daily

Protocol:
Take 5 grams once daily on an empty stomach.

L-glutamine is one of the most abundant amino acids in the human body and is an important fuel source for the rapidly dividing cells lining the intestinal tract.

Because intestinal cells have substantial energy requirements, glutamine has received considerable attention for its potential role in maintaining intestinal barrier integrity and tight-junction function.

Human research provides some support for this concept. A randomized, double-blind, placebo-controlled trial involving people with post-infectious IBS and increased intestinal permeability found that glutamine supplementation significantly improved intestinal permeability as well as gastrointestinal symptoms.

It is important to note that this study used 5 grams three times per day, rather than the 5-gram once-daily dose used in our protocol. Therefore, we use 5 grams daily as a nutritional-support dose rather than claiming that this specific dose has been proven to treat intestinal permeability.

Why we include it:
L-glutamine provides nutritional support to intestinal epithelial cells and may help support the structures involved in maintaining the intestinal barrier.

2. Zinc Carnosine — 75 mg Twice Daily

Protocol:
Take 75 mg with food, twice daily.

Zinc carnosine combines the essential mineral zinc with the amino-acid-derived compound L-carnosine.

Unlike ordinary zinc supplements, zinc carnosine has been studied specifically for its effects within the gastrointestinal tract.

In a randomized crossover study, researchers deliberately increased intestinal permeability in healthy volunteers using the NSAID indomethacin. Intestinal permeability increased approximately threefold without zinc carnosine. When zinc carnosine was administered, researchers did not observe the same significant increase in permeability.

Laboratory portions of the study also demonstrated increased migration and proliferation of intestinal epithelial cells, processes that are important during tissue repair.

The human study used 37.5 mg twice daily, so it should not be interpreted as direct validation of every zinc-carnosine dose used clinically.

Why we include it:
Zinc carnosine may help support gastrointestinal mucosal integrity, epithelial repair processes, and normal intestinal barrier function.

3. Phosphatidylcholine — 900 mg Daily

Protocol:
Take 900 mg per day.

Phosphatidylcholine is a phospholipid and an important structural component of cell membranes. It also plays an interesting role within the gastrointestinal tract.

Phosphatidylcholine contributes to the protective phospholipid layer associated with intestinal mucus. This layer helps create a barrier between the intestinal lining and substances contained within the digestive tract.

Clinical research involving specialized delayed-release phosphatidylcholine preparations has demonstrated improvements in intestinal mucosal outcomes in patients with ulcerative colitis.

These studies used specialized intestinal-release formulations and generally higher doses than 900 mg, so they should not be interpreted as proof that a standard 900-mg supplement treats ulcerative colitis or increased intestinal permeability.

Instead, phosphatidylcholine is included in this protocol as nutritional support for healthy cellular membranes and the gastrointestinal mucosal barrier.

Why we include it:
Phosphatidylcholine supplies important phospholipids involved in cell membranes and the protective intestinal mucus layer.

4. Collagen Peptides — 10 Grams Daily

Protocol:
Take 10 grams per day.

Collagen peptides provide amino acids including glycine, proline, and hydroxyproline, which the body can use as building blocks for connective tissues.

The intestinal lining and the connective tissue underneath it require a continuous supply of amino acids for normal tissue maintenance and repair.

For that reason, collagen peptides can be a useful nutritional addition to a gut-support program.

However, the evidence here needs to be kept in perspective. Human clinical evidence showing that collagen peptides directly reduce intestinal permeability is currently limited. A randomized clinical trial is evaluating doses of 2.5, 5, and 10 grams per day and their effects on intestinal permeability, but the study is still ongoing.

Therefore, collagen should be viewed primarily as a source of supportive amino acids rather than a proven treatment for increased intestinal permeability.

Why we include it:
Collagen provides amino acids that can contribute to normal connective-tissue and gastrointestinal tissue maintenance.

5. Deglycyrrhizinated Licorice (DGL) — 2 Tablets Before Meals

Protocol:
Chew or take 2 tablets before meals, according to the product directions.

Deglycyrrhizinated licorice, commonly called DGL, is a specially processed form of licorice in which most of the glycyrrhizin has been removed.

Traditional licorice preparations have long been used for gastrointestinal complaints, and DGL became particularly popular because removing glycyrrhizin substantially reduces concerns associated with excessive licorice consumption, including effects on blood pressure and potassium.

DGL is primarily used to support the mucosal defenses of the stomach and upper gastrointestinal tract.

Older clinical studies investigated deglycyrrhizinated licorice in people with gastric ulcers. While this provides some evidence for gastrointestinal mucosal support, research directly demonstrating that DGL decreases intestinal permeability is lacking.

Why we include it:
DGL may provide additional nutritional support for the protective mucosal environment of the gastrointestinal tract.

Putting the Protocol Together

A simple daily schedule might look like this:

Morning — Empty Stomach
L-Glutamine — 5 grams

Before Breakfast
DGL — 2 tablets

With Breakfast
Zinc Carnosine — 75 mg

During the Day
Phosphatidylcholine — 900 mg total
Collagen Peptides — 10 grams

Before Lunch and Dinner
DGL — 2 tablets before each meal

With Dinner
Zinc Carnosine — 75 mg

Supplements Are Only Part of the Equation

A gut-support protocol works best when the underlying factors affecting the gastrointestinal tract are also addressed.

Depending on the individual, this may include evaluating diet, alcohol intake, medications such as NSAIDs, food intolerances, gastrointestinal infections, inflammatory bowel conditions, stress, sleep, and overall nutrition.

Persistent abdominal pain, blood in the stool, unexplained weight loss, persistent diarrhea, anemia, fever, or significant changes in bowel habits should be evaluated by a healthcare professional rather than treated with supplements alone.

Three Research Articles Supporting This Approach

1. L-Glutamine and Intestinal Permeability

Zhou Q, et al. Randomised placebo-controlled trial of dietary glutamine supplements for postinfectious irritable bowel syndrome. Gut. 2019.

This randomized, double-blind, placebo-controlled study examined people with post-infectious IBS-D and increased intestinal permeability. Participants receiving glutamine experienced improvements in intestinal permeability and gastrointestinal symptoms compared with placebo. The study used 5 grams three times daily, so it supports glutamine's potential role in intestinal barrier function but does not directly establish the 5-gram once-daily dose used in this protocol.

2. Zinc Carnosine and Small-Intestinal Integrity

Mahmood A, et al. Zinc carnosine, a health food supplement that stabilises small bowel integrity and stimulates gut repair processes. Gut. 2007.

Researchers found that zinc carnosine stimulated intestinal epithelial cell migration and proliferation in laboratory experiments. In the human portion of the study, indomethacin substantially increased intestinal permeability with placebo, while the significant increase was prevented when zinc carnosine was administered.

3. Phosphatidylcholine and the Intestinal Mucosal Barrier

Karner M, et al. First multicenter study of modified release phosphatidylcholine “LT-02” in ulcerative colitis: a randomized, placebo-controlled trial in mesalazine-refractory courses. American Journal of Gastroenterology. 2014.

This randomized, double-blind, placebo-controlled study investigated modified-release phosphatidylcholine in people with ulcerative colitis. The researchers described phosphatidylcholine as an important component of the intestinal mucosal barrier and found improvement in disease activity with the studied formulation.

The Bottom Line

The intestinal barrier is a dynamic tissue that continually renews itself. Providing the body with appropriate nutrients may help support this normal repair and maintenance process.

Our five-part gut-support protocol focuses on:

L-Glutamine — 5 g/day
Provides nutritional support for intestinal epithelial cells.

Zinc Carnosine — 75 mg twice daily
Supports gastrointestinal mucosal integrity and repair processes.

Phosphatidylcholine — 900 mg/day
Provides phospholipids important for cell membranes and the intestinal mucus barrier.

Collagen Peptides — 10 g/day
Provides amino acids used throughout connective and gastrointestinal tissues.

DGL — 2 tablets before meals
Supports the protective gastrointestinal mucosal environment.

The goal isn't simply to cover up digestive symptoms. It is to provide the intestinal tract with nutritional support while identifying and addressing the factors that may be interfering with normal gut function.