Supplements for gut health: what the human evidence shows

109 supplements in our encyclopedia have at least one graded human outcome for gut health. Each row shows the strongest one, ranked by grade and then by the number of people studied. A high grade means the research is solid, not that the effect is large: open the row for the size of the effect and the dose tested.

Library last checked Supplement & Nutrient Encyclopedia How we grade evidence

Graded for gut
109
Best grade
A
Articles
8
Related pages
1

Best grade for gut

Strongest trial per supplement

Each supplement is shown once, at its best grade for gut health. The number is how many people were in that strongest study; for a meta-analysis, all its trials combined.

Grade A3 supplements

At least two concordant randomized controlled trials (RCTs), or a meta-analysis of RCTs, with a combined total of 300 or more participants.

Grade B14 supplements

At least one adequately powered RCT, or a consistent set of smaller RCTs.

Grade C52 supplements

Small or short RCTs, or trials with mixed results.

Show all 52Show fewer
Grade D38 supplements

A single small trial, or uncontrolled human data (open-label, before-and-after).

Show all 38Show fewer
No effect2 supplements

Adequately powered RCTs that found no effect on the outcome.

Grades run A to D per compound and outcome, never per product.

Compounds for gut

Every encyclopedia entry with a graded human outcome for gut health: its strongest outcome, the study behind it and the form tested.

Gut compounds, graded

Strongest first · 109 entries
Supplements with graded human evidence for gut health, strongest first
SupplementGrade for gutStrongest outcomeStudy
ProbioticsOther · checked Oct 21, 2026Grade ADiarrhea risk during antibiotic treatmentImproved · Form tested: Saccharomyces boulardii (yeast) vs placebo or no treatmentMeta-analysis n = 4,780 20155 graded rows for this goal
Saccharomyces boulardiiOther · checked Oct 21, 2026Grade AAntibiotic-associated diarrheaImproved · Form tested: Saccharomyces boulardiiMeta-analysis n = 4,780 20156 graded rows for this goal
Inulin (inulin-type fructans)Other · checked Oct 21, 2026Grade ABifidobacterium in the gutImproved · Form tested: Chicory-derived inulin-type fructans in foods or supplementsMeta-analysis n = 2,525 20234 graded rows for this goal
DiosminOther · checked Oct 21, 2026Grade BBleeding, pain and swelling after hemorrhoid surgery (MPFF)Improved · Form tested: Micronized purified flavonoid fraction (MPFF): diosmin with hesperidinMeta-analysis n = 2,335 20222 graded rows for this goal
Bentonite ClayOther · checked Oct 21, 2026Grade BDuration of acute infectious diarrhea in childrenImproved · Form tested: Dioctahedral smectite (diosmectite), a pharmaceutical clay, added to rehydration; bentonite was not studiedMeta-analysis n = 2,209 20187 graded rows for this goal
PsylliumBotanical · checked Oct 21, 2026Grade BClinical response in irritable bowel syndromeImproved · Form tested: Fiber supplements; psyllium in 6 of the 30 trialsMeta-analysis n = 1,904 20265 graded rows for this goal
GingerBotanical · checked Oct 21, 2026Grade BNausea in pregnancyImproved · Form tested: Oral ginger (capsules, syrup, powder)Meta-analysis n = 1,278 20143 graded rows for this goal
Peppermint OilBotanical · checked Oct 21, 2026Grade BGlobal IBS symptoms and abdominal painImproved · Form tested: Peppermint oil capsules (mostly enteric-coated)Meta-analysis n = 1,030 20226 graded rows for this goal
Lactobacillus reuteriOther · checked Oct 21, 2026Grade BTreatment response (at least 50% less crying) and daily crying time in infant colicImproved · Form tested: L. reuteri DSM 17938, single strainMeta-analysis n = 555 20265 graded rows for this goal
Lactobacillus plantarum 299v (Lp299v)Other · checked Oct 21, 2026Grade BIBS symptoms (abdominal pain severity, incomplete evacuation, symptom-improvement rates)Improved · Form tested: L. plantarum 299v (DSM 9843), single strainMeta-analysis n = 521 20266 graded rows for this goal
Saccharomyces cerevisiae CNCM I-3856 (probiotic yeast)Other · checked Oct 21, 2026Grade BAbdominal pain in constipation-predominant IBSImproved · Form tested: S. cerevisiae CNCM I-3856 capsulesRCT n = 456 20225 graded rows for this goal
Bifidobacterium bifidumOther · checked Oct 21, 2026Grade BAbdominal pain plus adequate relief of IBS symptomsImproved · Form tested: Heat-inactivated (non-viable) B. bifidum MIMBb75RCT n = 443 20205 graded rows for this goal
Bacillus coagulans (spore-forming probiotic)Other · checked Oct 21, 2026Grade BIBS symptoms (Unique IS2)Improved · Form tested: B. coagulans Unique IS2Meta-analysis n = 249 20267 graded rows for this goal
Magnesium sulfate (Epsom salt)Mineral · checked Oct 21, 2026Grade BFunctional constipation in women (mineral water)Improved · Form tested: Magnesium sulfate-rich natural mineral water (Hépar) vs low-mineral waterRCT n = 244 20145 graded rows for this goal
Licorice root (Glycyrrhiza glabra)Botanical · checked Oct 21, 2026Grade BReflux symptoms and reflux-related quality of lifeImproved · Form tested: GutGard deglycyrrhizinated licorice extract (glycyrrhizin ≤3.0%, glabridin ≥3.5%)RCT n = 200 20252 graded rows for this goal
Magnesium oxideMineral · checked Oct 21, 2026Grade BOverall improvement in chronic constipationImproved · Form tested: magnesium oxideRCT n = 90 20212 graded rows for this goal
SennaBotanical · checked Oct 21, 2026Grade BOverall symptom improvement in chronic idiopathic constipationImproved · Form tested: SennaRCT n = 90 20214 graded rows for this goal
Bacillus subtilisOther · checked Oct 21, 2026Grade CAntibiotic-associated diarrhea (two-strain product)Improved · Form tested: Live combined B. subtilis and Enterococcus faecium (granules or capsules)Meta-analysis n = 5,700 20267 graded rows for this goal
CranberryBotanical · checked Oct 21, 2026Grade CH. pylori eradicationNo effect · Form tested: cranberry productsMeta-analysis n = 1,935 2022
Bifidobacterium lactisOther · checked Oct 21, 2026Grade CDefecation frequency and gut comfort in adults with infrequent bowel movementsMixed · Form tested: BB-12 capsulesRCT n = 1,248 20157 graded rows for this goal
Cissus quadrangularisBotanical · checked Oct 21, 2026Grade CHemorrhoid symptomsNo effect · Form tested: Cissus alone or in combination productsMeta-analysis n = 1,108 2017
Turmeric and curcuminBotanical · checked Oct 21, 2026Grade CClinical remission in ulcerative colitis (add-on)Improved · Form tested: Curcumin added to standard therapy (administration method varied)Meta-analysis n = 482 2025
Galactooligosaccharides (GOS)Other · checked Oct 21, 2026Grade CGut symptoms in students during exam stressImproved · Form tested: GOSRCT n = 427 20115 graded rows for this goal
YaconBotanical · checked Oct 21, 2026Grade CBMI and bowel function (pooled)Improved · Form tested: Yacon syrup, flour, freeze-dried powder or yacon-based productsMeta-analysis n = 425 20253 graded rows for this goal
KiwifruitBotanical · checked Oct 21, 2026Grade CConstipation: bowel movements, pain and strainingImproved · Form tested: Whole kiwifruit or kiwifruit extractsMeta-analysis n = 399 20226 graded rows for this goal
Lactase enzymeOther · checked Oct 21, 2026Grade CCrying and fussing time in infant colicNo effect · Form tested: Lactase drops added to milk or feedsSystematic review n = 391 20247 graded rows for this goal
Bifidobacterium longumOther · checked Oct 21, 2026Grade CIBS symptoms (abdominal pain, bloating, bowel habit)Improved · Form tested: B. infantis 35624 capsulesRCT n = 362 20063 graded rows for this goal
Aloe VeraBotanical · checked Oct 21, 2026Grade CIBS global symptom responseNo effect · Form tested: Aloe vera juice or Aloe barbadensis extract tabletsMeta-analysis n = 299 20267 graded rows for this goal
Activated CharcoalOther · checked Oct 21, 2026Grade CFunctional dyspepsia symptoms (charcoal, simethicone and magnesium oxide)Improved · Form tested: Combination: simethicone, activated charcoal and magnesium oxide (Carbosymag)RCT n = 276 20114 graded rows for this goal
Artichoke ExtractBotanical · checked Oct 21, 2026Grade CFunctional dyspepsia symptoms and quality of lifeImproved · Form tested: Commercial artichoke leaf extractRCT n = 247 20032 graded rows for this goal
AndrographisBotanical · checked Oct 21, 2026Grade CClinical response in mild-to-moderate ulcerative colitisMixed · Form tested: Andrographis paniculata extract (HMPL-004)RCT n = 224 2013
Clostridium butyricumOther · checked Oct 21, 2026Grade COverall symptoms, quality of life and stool frequency in diarrhea-predominant IBSImproved · Form tested: C. butyricum capsules (420 mg per capsule)RCT n = 200 20186 graded rows for this goal
TUDCA (tauroursodeoxycholic acid)Other · checked Oct 21, 2026Grade CLiver enzyme (ALP) response compared with the drug UDCAImproved · Form tested: TUDCARCT n = 199 20163 graded rows for this goal
PolydextroseOther · checked Oct 21, 2026Grade CColonic transit and bowel movements in functional constipationMixed · Form tested: Polydextrose (Litesse Ultra)RCT n = 192 20196 graded rows for this goal
Guar GumOther · checked Oct 21, 2026Grade CIBS pain and bowel habits versus wheat branImproved · Form tested: Partially hydrolyzed guar gum (PHGG)Open-label trial n = 188 20025 graded rows for this goal
Acacia FiberOther · checked Oct 21, 2026Grade CStool frequency and symptoms in IBS with constipationImproved · Form tested: Acacia fibre powderRCT n = 180 20242 graded rows for this goal
Burdock Root (Arctium lappa)Botanical · checked Oct 21, 2026Grade CRecurrence of diverticulitis and diverticular bleedingMixed · Form tested: Burdock teaRCT n = 161 20192 graded rows for this goal
Streptococcus salivarius K12Other · checked Oct 21, 2026Grade CSevere mouth sores (oral mucositis) during head and neck radiotherapyImproved · Form tested: K12 lozenges sucked three times a dayRCT n = 160 20243 graded rows for this goal
AlanylglutamineAmino acid · checked Oct 21, 2026Grade CGut permeability and growth in undernourished childrenImproved · Form tested: Alanyl-glutamine versus glycine placeboRCT n = 140 20203 graded rows for this goal
ButyrateFatty acid · checked Oct 21, 2026Grade CDisease activity and quality of life in IBD (add-on to standard therapy)Mixed · Form tested: Microencapsulated butyrateRCT n = 140 20268 graded rows for this goal
TroxerutinOther · checked Oct 21, 2026Grade CPain, bleeding, swelling and thrombosis in an acute hemorrhoid attackImproved · Form tested: Mixture of diosmin, troxerutin and hesperidinRCT n = 134 2015
Glucomannan (konjac)Other · checked Oct 21, 2026Grade CFunctional constipation in childrenMixed · Form tested: GlucomannanMeta-analysis n = 122 2017
FennelBotanical · checked Oct 21, 2026Grade CInfant colic (crying under 9 hours a week)Improved · Form tested: Fennel seed oil emulsion vs placeboRCT n = 121 2003
Anise (Aniseed)Botanical · checked Oct 21, 2026Grade CIBS symptoms (freedom from symptoms) vs placebo and peppermint oilImproved · Form tested: Enteric-coated anise oil capsules (AnisEncap) vs placebo vs Colpermin peppermint oilRCT n = 120 20163 graded rows for this goal
Digestive enzymesOther · checked Oct 21, 2026Grade CFunctional dyspepsia symptoms and quality of lifeImproved · Form tested: Multi-enzyme blend from fungal fermentation vs placeboRCT n = 120 20235 graded rows for this goal
Stevia (steviol glycosides)Botanical · checked Oct 21, 2026Grade CGlucose tolerance and gut microbes after 2 weeks of sweetener sachetsMixed · Form tested: Stevia sachets (below the acceptable daily intake)RCT n = 120 20222 graded rows for this goal
XylitolOther · checked Oct 21, 2026Grade CGas and diarrhoea in toddlers on daily xylitol solutionNo effect · Form tested: Oral xylitol solution vs placeboRCT n = 120 20072 graded rows for this goal
Lactobacillus gasseriOther · checked Oct 21, 2026Grade CFunctional dyspepsia without H. pylori infectionImproved · Form tested: Yogurt with OLL2716 (placebo: yogurt without it)RCT n = 116 2017
L-glutamineAmino acid · checked Oct 21, 2026Grade CSymptoms of post-infectious IBS with diarrhoeaImproved · Form tested: Oral glutamineRCT n = 106 2019
Serum Bovine Immunoglobulin (SBI)Other · checked Oct 21, 2026Grade CDaily unformed stools and GI symptomsNo effect · Form tested: SBIRCT n = 103 20173 graded rows for this goal
Castor OilBotanical · checked Oct 21, 2026Grade CBowel cleansing before barium enemaNo effect · Form tested: Castor oil vs sodium phosphate preparationRCT n = 100 20092 graded rows for this goal
Human Milk Oligosaccharides (HMOs)Other · checked Oct 21, 2026Grade CGut symptoms and stool bacteriaImproved · Form tested: 2'-fucosyllactose (2'-FL) and/or lacto-N-neotetraose (LNnT), made by chemical synthesisRCT n = 100 20164 graded rows for this goal
Yeast mannanOther · checked Oct 21, 2026Grade CGut bacteria, putrefactive compounds and bowel habitsImproved · Form tested: Yeast mannan tablets vs maltose placeboRCT n = 100 20203 graded rows for this goal
Xylooligosaccharides (XOS)Other · checked Oct 21, 2026Grade CFunctional constipation symptomsImproved · Form tested: XOS vs fructo-oligosaccharides vs placeboRCT n = 93 20244 graded rows for this goal
Shirazi thyme (Zataria multiflora)Botanical · checked Oct 21, 2026Grade CColitis symptoms and antioxidant markersImproved · Form tested: Zataria multiflora extract vs placeboRCT n = 92 20252 graded rows for this goal
Apple pectinOther · checked Oct 21, 2026Grade CDiarrhoea-type IBS symptomsImproved · Form tested: Pectin powderRCT n = 87 20153 graded rows for this goal
Prunes (Dried Plums)Botanical · checked Oct 21, 2026Grade CHard stools and constipation complaintsImproved · Form tested: Prune juice (sorbitol, pectin, polyphenols)RCT n = 84 20223 graded rows for this goal
EpiCor (dried yeast fermentate)Other · checked Oct 21, 2026Grade CBloating and constipation symptomsMixed · Form tested: EpiCor dried yeast fermentatePilot RCT n = 80 2017
Nopal (Prickly Pear Cactus)Botanical · checked Oct 21, 2026Grade CGut microbiota and digestive comfortImproved · Form tested: Odilia Opuntia ficus-indica extractRCT n = 80 20242 graded rows for this goal
FlaxseedBotanical · checked Oct 21, 2026Grade CConstipation symptomsImproved · Form tested: baked flaxseed in cookiesRCT n = 77 20192 graded rows for this goal
ErythritolOther · checked Oct 21, 2026Grade CGut symptoms after one large dose in a drinkMixed · Form tested: Erythritol or xylitol in water vs 45 g sucroseRCT n = 64 20072 graded rows for this goal
AsafoetidaBotanical · checked Oct 21, 2026Grade CFunctional dyspepsia symptoms (early satiety, bloating, heartburn)Improved · Form tested: Food-grade self-emulsifying hydrogel of asafoetida oleo-gum resin (Asafin) vs placeboRCT n = 62 20252 graded rows for this goal
Jujube (Ziziphus jujuba fruit)Botanical · checked Oct 21, 2026Grade CTreatment response in childhood functional constipationImproved · Form tested: Ziziphus jujuba syrup vs polyethylene glycol (PEG)RCT n = 62 20252 graded rows for this goal
Plantago major seeds (greater plantain seed)Botanical · checked Oct 21, 2026Grade CUlcerative colitis symptoms (Lichtiger Colitis Activity Index items)Mixed · Form tested: Roasted Plantago major seedRCT n = 61 2021
Glutathione (oral)Other · checked Oct 21, 2026Grade CGrowth and gut inflammation in children with cystic fibrosisNo effect · Form tested: oral reduced glutathione powderRCT n = 58 2020
Alpha-GalactosidaseOther · checked Oct 21, 2026Grade CGas-related symptoms in childrenImproved · Form tested: Alpha-galactosidase drops or tabletsRCT n = 52 20136 graded rows for this goal
Zeolite (clinoptilolite)Mineral · checked Oct 21, 2026Grade CGut barrier and inflammation markers in endurance athletesMixed · Form tested: Zeolite vs placeboRCT n = 52 20155 graded rows for this goal
ArabinoxylanOther · checked Oct 21, 2026Grade CGut transit time and stool consistencyMixed · Form tested: Wheat bran arabinoxylan-oligosaccharides (AXOS) vs maltodextrinRCT n = 48 2020
Bovine colostrumOther · checked Oct 21, 2026Grade CIntestinal permeability during running trainingWorsened · Form tested: bovine colostrumRCT n = 30 20092 graded rows for this goal
MethylcelluloseOther · checked Oct 21, 2026Grade DConstipation symptoms (stool frequency, consistency, ease of passage)Improved · Form tested: Methylcellulose powderObservational n = 538 19895 graded rows for this goal
Rhamnogalacturonan-I (carrot RG-I)Other · checked Oct 21, 2026Grade DGut microbiota composition (same challenge trial)Mixed · Form tested: Carrot-derived RG-I (cRG-I)RCT n = 146 20242 graded rows for this goal
L-AlanineAmino acid · checked Oct 21, 2026Grade DDuration of diarrhea in children with alanine rehydration solutionNo effect · Form tested: Oral rehydration solution with 90 mmol/L alanine and reduced glucoseRCT n = 129 19912 graded rows for this goal
Bifidobacterium breveOther · checked Oct 21, 2026Grade DAntibiotic-associated diarrhoea in children (strain PRL2020)Improved · Form tested: B. breve PRL2020 (an amoxicillin-resistant strain)Open-label trial n = 121 20264 graded rows for this goal
NoniBotanical · checked Oct 21, 2026Grade DPost-operative nausea and vomitingMixed · Form tested: Dried noni fruit extract capsulesRCT n = 100 2010
FucoidanOther · checked Oct 21, 2026Grade DGut symptoms and bacteria during H. pylori therapyImproved · Form tested: Fucoidan with or before standard quadruple therapyOpen-label trial n = 90 2023
Sea BuckthornBotanical · checked Oct 21, 2026Grade DBowel movements in chronic idiopathic constipationImproved · Form tested: Hydroethanolic sea buckthorn fruit extractRCT n = 90 2026
KefirOther · checked Oct 21, 2026Grade DH. pylori clearance with antibiotic triple therapyImproved · Form tested: Kefir vs milk with placebo, alongside antibioticsRCT n = 82 20113 graded rows for this goal
BromelainBotanical · checked Oct 21, 2026Grade DUlcerative colitis disease activity and quality of lifeMixed · Form tested: Oral bromelainRCT n = 70 2025
St. John's wortBotanical · checked Oct 21, 2026Grade DIrritable bowel syndrome symptomsNo effect · Form tested: St. John's wortRCT n = 70 2010
AmlaBotanical · checked Oct 21, 2026Grade DHeartburn and regurgitation in non-erosive reflux diseaseImproved · Form tested: Amla tabletsRCT n = 68 2018
BoswelliaBotanical · checked Oct 21, 2026Grade DKeeping Crohn's disease in remissionNo effect · Form tested: Boswelan (Boswellia serrata extract)RCT n = 66 20112 graded rows for this goal
Mastic gumBotanical · checked Oct 21, 2026Grade DH. pylori eradication when added to bismuth quadruple therapyMixed · Form tested: Mastic gum added to standard bismuth quadruple therapyPilot RCT n = 64 20265 graded rows for this goal
Purslane ExtractBotanical · checked Oct 21, 2026Grade DFunctional constipationImproved · Form tested: 70% ethanol extract of purslane aerial parts vs placeboRCT n = 60 2022
Clove (clove oil and clove bud extract)Botanical · checked Oct 21, 2026Grade DChronic anal fissure closure at 3 monthsImproved · Form tested: Clove oil 1% cream vs stool softeners plus lignocaine 5% creamRCT n = 55 2007
Agaricus blazei (Royal Sun Mushroom)Mushroom · checked Oct 21, 2026Grade DSymptoms, fatigue and quality of life in ulcerative colitisImproved · Form tested: AndoSan (Agaricus-based mushroom blend)RCT n = 50 20162 graded rows for this goal
PerillaBotanical · checked Oct 21, 2026Grade DBloating and abdominal discomfortMixed · Form tested: Proprietary Perilla frutescens extractPilot RCT n = 50 2014
Silk Amino Acids (Silk Peptide)Amino acid · checked Oct 21, 2026Grade DBowel movement frequency in constipationImproved · Form tested: Sericin/fibroin mixture drink fermented with Lactococcus lactis BM32-1RCT n = 50 2024
Brown Rice ProteinOther · checked Oct 21, 2026Grade DGut microbiota with protein supplementsMixed · Form tested: Rice protein isolate vs whey concentrate, pea isolate and a plant blendRCT n = 45 2026
Ellagic AcidOther · checked Oct 21, 2026Grade DIBS symptom severity and sleep qualityImproved · Form tested: Ellagic acidRCT n = 44 2021
Slippery elmBotanical · checked Oct 21, 2026Grade DDigestive symptoms with a multi-ingredient gut formulaImproved · Form tested: Formula with curcumin, aloe vera, slippery elm, guar gum, pectin, peppermint oil and glutamineOpen-label trial n = 43 20203 graded rows for this goal
KombuchaOther · checked Oct 21, 2026Grade DConstipation-predominant IBS in womenImproved · Form tested: Kombucha enriched with inulin (2.53 g) and B vitamins vs waterPilot RCT n = 40 20232 graded rows for this goal
Wormwood (Artemisia absinthium)Botanical · checked Oct 21, 2026Grade DCrohn's disease activity while steroids were taperedImproved · Form tested: Herbal blend containing wormwood herbRCT n = 40 20072 graded rows for this goal
TriphalaBotanical · checked Oct 21, 2026Grade DGut bacteria compositionMixed · Form tested: TriphalaPilot RCT n = 31 2020
Larch ArabinogalactanOther · checked Oct 21, 2026Grade DGut microbiome and digestive toleranceMixed · Form tested: ResistAid (proprietary larch arabinogalactan) versus maltodextrinCrossover RCT n = 30 20212 graded rows for this goal
Lithothamnion (Aquamin)Mineral · checked Oct 21, 2026Grade DColon bacteria and stool metabolitesMixed · Form tested: AquaminRCT n = 30 20203 graded rows for this goal
Chlorophyll (Chlorophyllin)Other · checked Oct 21, 2026Grade DFecal odor in colostomy patientsNo effect · Form tested: chlorophyll tabletsCrossover RCT n = 28 19893 graded rows for this goal
Turkey tail mushroom (Trametes versicolor)Mushroom · checked Oct 21, 2026Grade DGut microbiome compositionMixed · Form tested: PSP from Trametes versicolor vs amoxicillin vs no treatmentRCT n = 24 2014
Bhringaraj (Eclipta alba)Botanical · checked Oct 21, 2026Grade DHyperacidity (amlapitta) symptomsImproved · Form tested: Bhringaraja (Eclipta alba) tablets vs rice-powder placebo tabletsPilot RCT n = 22 2011
XanthohumolOther · checked Oct 21, 2026Grade DSafety and metabolic markers in Crohn diseaseMixed · Form tested: XanthohumolRCT n = 20 2026
WheatgrassBotanical · checked Oct 21, 2026Grade DDisease activity and rectal bleeding in active distal ulcerative colitisImproved · Form tested: Fresh wheatgrass juiceRCT n = 19 2002
GABAAmino acid · checked Oct 21, 2026Grade DSymptoms of diarrhoea-predominant irritable bowel syndromeImproved · Form tested: GABA plus lemon balm (Melissa officinalis) extract tabletsCrossover RCT n = 18 2026
LactosucroseOther · checked Oct 21, 2026Grade DBody weight in underweight inpatients with schizophreniaImproved · Form tested: Lactosucrose, no control groupOpen-label trial n = 16 20182 graded rows for this goal
OreganoBotanical · checked Oct 21, 2026Grade DGut parasites in stoolImproved · Form tested: Emulsified oil of Mediterranean oregano (Origanum vulgare)Open-label trial n = 14 2000
N-Acetyl Glucosamine (NAG)Other · checked Oct 21, 2026Grade DDisease activity in severe childhood inflammatory bowel diseaseImproved · Form tested: N-acetyl glucosamine (oral, add-on)Open-label trial n = 12 2000
Sea moss (Irish moss)Botanical · checked Oct 21, 2026Grade DRelapse in ulcerative colitis with carrageenanWorsened · Form tested: carrageenan capsules (the main fibre in sea moss), not sea mossRCT n = 12 20172 graded rows for this goal
Zinc carnosineMineral · checked Oct 21, 2026Grade DPainkiller-induced gut permeabilityImproved · Form tested: Zinc carnosineCrossover RCT n = 10 20072 graded rows for this goal
Betaine HClOther · checked Oct 21, 2026Grade DRe-acidifying the stomach after a mealMixed · Form tested: Betaine HCl capsulesCrossover RCT n = 9 20192 graded rows for this goal
Lactobacillus helveticusOther · checked Oct 21, 2026No effectModerate-to-severe stomach illness in young childrenNo effect · Form tested: L. rhamnosus R0011 plus L. helveticus R0052RCT n = 886 2018
Wheat DextrinOther · checked Oct 21, 2026No effectCalcium and magnesium absorptionNo effect · Form tested: Wheat dextrin vs placeboCrossover RCT n = 40 2011
Grades follow our methodology. A “no effect” grade means good trials found no benefit. Amounts in trials are what was studied, not advice for you. What each costs a month at the studied dose: Evidence per Dollar.

Articles

Research reads built on the graded evidence above, for the supplements in this hub.

Research reads

8 articles

Find the evidence

Ask our graded human trials about a goal, a grade, a trial size, two supplements or a medicine. Answers are assembled on your device from the rows.

Evidence finder

3,342 trial rows · 869 interaction rows

162 graded trial rows on gut and digestion that showed a benefit, across 77 supplements. Best grade among rows showing a benefit: A.

Grades of the 162 rows: A 3B 24C 64D 71

Strongest row showing a benefit, per supplement

  1. ProbioticsGrade A

    Diarrhea risk during antibiotic treatment

    Improved · 4,780 people · Meta‑analysis · 2015 · 2 more matching rows

  2. Saccharomyces boulardiiGrade A

    Antibiotic-associated diarrhea

    Improved · 4,780 people · Meta‑analysis · 2015 · 2 more matching rows

  3. Inulin (inulin-type fructans)Grade A

    Bifidobacterium in the gut

    Improved · 2,525 people · Meta‑analysis · 2023 · 3 more matching rows

Assembled from 162 graded trial rows when this page was built.

Fixed sentence templates filled from our rows; every line links to its row. Not medical advice.

Educational information only, not medical advice. Dietary supplements are not intended to diagnose, treat, cure or prevent any disease.

Educational only. Not medical advice. Some links earn us a commission: kymatahealth.com/affiliate-disclosure.