Is a higher dose always better?

No. Dose-fit rewards landing inside the range studied for the outcome — over-dosing (common with melatonin) or under-dosing both lower the score. The goal is the effective dose, not the biggest number.

What does the Value score mean?

The Value score compares a product's price per serving with clinically relevant products ranked for the same outcome. A score of 50 is the typical price; above 50 means better value than typical, while below 50 means the product costs more than typical. It is a 0–100 value signal, not a percentile.

Why is the cheapest product not #1?

Cost is only one input. The cheapest pick here is a citrate form with weaker absorption and a stock-risk flag, so it leads on Value-for-cost but trails on the composite that also weighs evidence, dose fit and availability.

Are these affiliate links?

Retailer links may be affiliate links and DoseRank may earn a commission. Rankings and placement are determined by the scoring model only — never by payment from a brand.

Is this medical advice?

No. DoseRank summarizes evidence to help you choose; it is not a substitute for a clinician, especially if you are pregnant, breastfeeding, on medication, or managing a health condition.

Reduce intestinal permeability

What this outcome means

Intestinal permeability describes how tightly your gut lining holds together and how much it lets pass between the digestive tract and bloodstream. On DoseRank it maps to a defined health outcome built from human studies on lactulose-mannitol ratios, zonulin levels, and tight-junction integrity markers – data sourced from open sources and specialized resources. DoseRank is not medical advice.

Who it's for

Digestive sensitivityPeople with ongoing bloating, discomfort, or food reactions.

Gut-barrier curiousThose exploring whether a leaky gut lining affects their symptoms.

Post-illness recoveryAnyone rebuilding gut health after infection, stress, or antibiotics.

Stack buildersAlready taking supplements such as Zinc Carnosine and want the dose right.

Evidence level

78Moderate-strong

Zinc Carnosine – has moderate public evidence for this outcome. This usually means there are smaller or mechanistic studies, but not randomized human trials. A DoseFit Score of 93 means this product's ingredient forms and doses are close to what was used in the studies behind this ranking - DoseRank weights each product ingredient.

Best available ingredients

Zinc Carnosine is the best supported ingredient signal for this outcome.

Dose matchedDoseFit 93

Scores reward products dosed inside or above the studied range, not just the right ingredient. Examples: Above range: Zinc Carnosine 74 mg vs 17-33.9 mg.

Processed

677

Available

677

Ingredients

Brands

142

Coverage

100%

How to read the scores

What every metric means

Each score is 0–100. Higher is better for every metric below.

CompositeThe overall DoseRank score — a weighted blend of clinical strength, evidence, dose fit, trust and value.Higher is better

ClinicalHow strongly the formula's ingredients and doses match what clinical studies used for this outcome.Higher is better

EvidenceHow much published human research backs the formula's key ingredients for this outcome — both how many studies exist and how strong they are.Higher is better

ValueHow the price per serving compares with similar products for this outcome — 50 is the typical price, higher means better value for your money.Higher is better

TrustHow well customers rate this product, with extra weight given to ratings backed by a large number of reviews.Higher is better

PopularityHow strongly this product sells compared with the other ranked products for this outcome.Higher is better

This legend covers the scores on this page — for data sources, scoring weights, and limits, read the full methodology →

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A saved, shareable breakdown: your matched products, dose math, interaction flags to discuss with a clinician, and a price-tracked stack you can revisit.

Questions

Frequently asked

Each product gets a composite score blending clinical strength, evidence, dose fit, trust and value. The #1 on the DoseRank tab has the highest composite; the other tabs re-rank the same products by Value, Trust, or Popularity. Placement is never paid.

Reduce intestinal permeability

What this outcome means

Who it's for

Digestive sensitivityPeople with ongoing bloating, discomfort, or food reactions.

Gut-barrier curiousThose exploring whether a leaky gut lining affects their symptoms.

Post-illness recoveryAnyone rebuilding gut health after infection, stress, or antibiotics.

Stack buildersAlready taking supplements such as Zinc Carnosine and want the dose right.

Evidence level

78Moderate-strong

Best available ingredients

Zinc Carnosine is the best supported ingredient signal for this outcome.

Dose matchedDoseFit 93

Scores reward products dosed inside or above the studied range, not just the right ingredient. Examples: Above range: Zinc Carnosine 74 mg vs 17-33.9 mg.

Processed

677

Available

677

Ingredients

Brands

142

Coverage

100%

Relevant ingredients

Which ingredient types matter for intestinal permeabilityOpen to see which ingredient types matter for intestinal permeability

508 products across 4 ingredient types — open to filter the ranking.

Use types to filter ranked products

Amino Acids & Derivatives

397 products

The building blocks of protein, taken singly for targeted effects – leucine for muscle, theanine for calm. Free-form versions absorb fast on an empty stomach.

Typical: ,

Minerals & Trace Elements

51 products

Inorganic nutrients from calcium to zinc. The chemical form drives absorption – chelates and citrates usually beat cheap oxides.

Typical:

Fatty Acids & Lipids

15 products

Dietary fats including omega-3s and structural lipids. Look at the active EPA/DHA amounts and freshness, since oils oxidize and turn rancid.

Typical:

Glandulars & Animal-Derived Extracts

45 products

Animal gland and organ-tissue extracts used traditionally for targeted organ support. Purity and grass-fed sourcing are the key quality markers.

Typical:

Top decision cards

Best products for intestinal permeability

Ranking by · Composite outcome score

Best overall — the composite outcome score.

Top pick · DoseRank

Why this ranks #1 for intestinal permeability

California Gold Nutrition, Zinc-L-Carnosine Complex, 90 Veggie Capsules

California Gold Nutrition$0.23 / serving4.8 · 6,111Available now

Also helps with

Gut barrier function

Zinc status

Gastrointestinal symptom burden

Why this ranks here

Evidence fitZinc Carnosine has moderate human evidence for this outcome.
Dose fitZinc Carnosine at 74 mg is higher than the studied 17-33.9 mg window.
Price / serving$0.23 per serving — mid price tier for this outcome.
AvailabilityIn stock across major retailers; 99% availability confidence.
TrustStrong trust signals — consistently high marks from verified buyer ratings.

The numbers

74 mgAbove rangehigher than the studied 17-33.9 mg window

Compare top 3 Product data Open at retailer

The rest of the ranking · DoseRank

Top 10 ranked products

Nutricost, L-Glutamine, Unflavored, 35.7 oz (1 kg)

NutricostClinical87Dose fit67Popularity91$0.13/ serving

Force Factor, Zinc-L-Carnosine Complex, 120 Vegetable Capsules

Force FactorClinical89Dose fit93Popularity76$0.29/ serving

California Gold Nutrition, Sport, L-Glutamine Powder, AjiPure®, Gluten Free, 1 lb (454 g)

California Gold NutritionClinical87Dose fit67Popularity98$0.25/ serving

Doctor's Best, Pure L-Glutamine Powder, 10.6 oz (300 g)

Doctor's BestClinical87Dose fit67Popularity98$0.28/ serving

NOW Foods, Sports, L-Glutamine Powder, 1 lb (454 g)

NOW FoodsClinical87Dose fit67Popularity89$0.26/ serving

MuscleTech, Platinum 100% Glutamine, Unflavored, 10.58 oz (300 g)

MuscleTechClinical87Dose fit67Popularity84$0.25/ serving

NOW Foods, Sports, L-Glutamine Powder, 2.2 lbs (1 kg)

NOW FoodsClinical87Dose fit67Popularity76$0.22/ serving

ALLMAX, Essentials, Glutamine, 2.2 lbs (1,000 g)

ALLMAXClinical87Dose fit67Popularity80$0.24/ serving

EVLution Nutrition, Glutamine5000®, Unflavored, 10.58 oz (300 g)

EVLution NutritionClinical87Dose fit67Popularity76$0.23/ serving