Null and negative results
120 of the 1,884 studies with a recorded outcome direction (6%) report a neutral, negative or mixed result for hydrogen, 31 of them in people. Most sites about hydrogen never mention them. They matter more than their number suggests: in a literature where 94% of published results are positive, the studies that found nothing are the ones that tell you how large the real effect could be.
How a study gets here: our pipeline records the direction of each study's main result from its abstract (positive, neutral, negative or mixed). A study is listed when that field is anything but positive. The classification is machine-drafted and checked in audits; if a study below is misclassified, tell us. The wider context is on the limits of the evidence.
In people (31)
- Fiber Gels Reduce Gut Gas From Fermentable Foods in Healthy Adults
- Your Gut Bacteria May Determine If Hydrogen Therapy Improves Your Sleep
- Hydrogen Gas Inhalation Shows No Benefit for Infant Epilepsy Spasms
- Hydrogen Water Shows Mixed Results for Mountain Sickness Patients
- Hydrogen Inhalation Slightly Lowers Oxygen Levels in Healthy Women
- Hydrogen Gas Shows Promise for Heart Surgery Emergency Recovery
- Hydrogen Water May Help Soccer Players Recover Faster After Games
- Hydrogen Jelly Shows Promise for Gum Disease Treatment in Clinical Trial
- Hydrogen Water Doesn't Help COVID-19 Patients Recover Faster
- Hydrogen Water Doesn't Boost Running Performance in Athletes
- Hydrogen Gas May Help Liver Surgery Recovery and Quality of Life
- Hydrogen Water Study Tests Memory and Health in Older Adults
- Gut Bacteria Fermentation Doesn't Affect Key Hunger Hormones in Men
- Hydrogen Gas Inhalation Shows No Benefit for Parkinson's Disease
- Hydrogen Water Affects Heart Rate in Healthy Women
- High-Dose Hydrogen Therapy May Weaken Immune System in Healthy Adults
- Hydrogen Supplements Show Mixed Effects on Exercise Performance
- Hydrogen Water Doesn't Boost Running Performance in Trained Athletes
- Hydrogen Water Doesn't Boost Exercise Performance in Heat
- Hydrogen Water Shows Mixed Results for Athletic Performance
- Hydrogen Water Study Tests Benefits for Parkinson's Disease Symptoms
- Hydrogen Baths Don't Help Exercise Muscle Damage, Study Finds
- Hydrogen Water Shows Promise for Parkinson's Disease Symptoms
- How Your Body Uses Hydrogen Gas When You Breathe It In
- Hydrogen Water Shows No Benefit for Bladder Pain in Clinical Trial
- How Much Hydrogen Water Actually Gets Used by Your Body
- Study Measures Hydrogen Gas Release Through Skin During Inhalation
- Hydrogen Water Shows Rapid But Short-Lived Absorption in Breath Tests
- Hydrogen Gas Breathing Causes Muscle Weakness in Deep Sea Divers
- Hydrogen Gas Effects on Heart During Extreme Deep Sea Diving Study
- Humphry Davy's Pioneering Study on Breathing Nitrous Oxide Gas
In animals, cells and reviews (89)
- Why Breathing Hydrogen Works Better Than Drinking Hydrogen Water
- Enzyme Supplement Eases Bloating and Pain from High-Fiber Foods
- Breath Test Identifies Bacterial Overgrowth Subtypes in Bloating Patients
- Gut Bacteria Differences Found in IBS Patients With Bacterial Overgrowth
- Hydrogen Breath Test Measures Gut Fermentation, Not Body-Wide Inflammation
- Gut Bacteria Hydrogen Production Linked to High Blood Pressure Risk
- Bowel Prep Drink Clears Gut Bacteria Overgrowth for 6 Weeks
- Can Diet or Hydrogen Water Help Interstitial Cystitis? A Review
- Why Older Adults Have Less Hydrogen in Their Breath After Sleep
- Breath Test Helps Diagnose Bacterial Overgrowth in IBS Patients
- H. pylori Infection Linked to Lower Breath Hydrogen and Gut Problems
- Hydrogen Water Shows Modest Cholesterol Benefits in Overweight Adults
- Different Types of SIBO Show Unique Gut Bacteria and Metabolism Patterns
- Breath Test Study Reveals How Gut Gases Link to Digestive Symptoms
- Breath Test Reveals How Gut Bacteria and Diet Affect Digestive Health
- Kids with Stomach Pain Have Slower Digestion Than Healthy Children
- Hydrogen Therapy Shows Promise for Parkinson's Disease Treatment
- Hydrogen Therapy Alone May Not Help Severe Intestinal Damage
- Hydrogen Gas Treatment for Intestinal Damage in Pigs Shows Promise
- Study Compares Two Tests for Diagnosing Small Intestine Bacterial Problems
- Kangaroo Gut Bacteria Reveal New Hydrogen Management Strategies
- Hydrogen Gas Links to Digestive Issues in Japanese Intestinal Disorder
- Multiple Food Intolerances Increase Hydrogen Levels in Breath Tests
- Breath Test Identifies IBS Patients Who Benefit from Antibiotics
- Hydrogen Gas Doesn't Help Intestinal Damage in Pig Study
- Breast Cancer Patients Show Different Gut Bacteria and Hydrogen Production
- Pharmacokinetics of Hydrogen-Saturated Saline in Pigs
- Hydrogen Water Health Benefits: What Science Says About This Trendy Drink
- Hydrogen Water Boosts Athletic Power But Not Endurance, Study Shows
- Can Hydrogen Water Reduce Exercise Stress? New Study Results
- Hydrogen Gas and Stress Response in Emergency Blood Flow in Piglets
- Hydrogen Device Explosion Causes Serious Lung Injury at Home
- Nanobubbles and Fibroblast Growth: An In Vitro Study on Cell Migration and Proliferation
- Mucuna Beans Show Promise for Advanced Parkinson's Disease Treatment
- Hydrogen Gas Inhalation Shows No DNA Damage Risk in Rats
- Hydrogen Gas and Solution in Spinal Cord Injury in Rabbits
- Hydrogen Water Reduces Exercise Fatigue But Doesn't Boost Performance
- Hydrogen Gas Showed Mixed Results for Brain Vessel Damage in Piglets
- Safety Concerns Found with High-pH Hydrogen Water from Ionizers
- Hydrogen May Boost Some Cancer Cells, Study Warns
- Lab Tests Suggest Hydrogen's Effects Aren't Mainly From Scavenging Hydroxyl Radicals
- How Inhaled Hydrogen Gas Moves Through the Body in Pigs
- Low-Flow Hydrogen Therapy Reaches Effective Blood Levels in Pigs
- Acidic Electrolyzed Water Inactivated SARS-CoV-2 in Lab Tests
- Ionized Water Harms Baby Development in Pregnant Rats Study Finds
- Electrolyzed Water Shows Promise Against Chagas Disease in Mice Study
- Inhaled Hydrogen Gas With Brain Cooling in Piglet Birth Injury Model
- Hydrogen Molecules and Stomach Enzyme Activity in Lab Tests
- Hydrogen Gas Distribution in Organs After Inhalation in Rats
- Hydrogen Water Shows No Benefit for Kidney Cysts in Rat Study
- Hydrogen Water May Preserve Liver Energy During Exercise in Rats
- Hydrogen Gas Fails to Protect Skin Grafts in Rats
- Hydrogen Water Shows Antibacterial and Antioxidant Effects in Lab Study
- Hydrogen Gas Shows Mixed Results for Eye Inflammation in Rats
- Hydrogen Water Protects Embryonic Cells from Oxidative Stress
- Hydrogen Nanobubble Water Shows Antioxidant Activity in Lab Tests
- Hydrogen Gas Fails to Protect Kidneys from Transplant Damage in Pig Study
- Hydrogen Gas Protects Liver from Sleep Apnea-Related Damage in Rats
- Hydrogen Water Shows Limited Benefits for Eye Inflammation in Rats
- How H. pylori Uses Hydrogen Gas to Spread Cancer-Causing Toxins in the Stomach
- Hydrogen Water Failed to Protect Against Eye Disease in Mice Study
- Hydrogen Therapy Fails to Help Stroke Recovery in Rats
- Acidic Electrolyzed Water Reduced Tooth Enamel Hardness in Lab Tests
- Hydrogen Water May Work Through Appetite Hormone to Protect Brain
- Hydrogen Therapy Shows Promise for Treating Pulmonary Hypertension
- Hydrogen Concentration in Rat Tissue After Various Administration Routes
- Hydrogen Water Shows Promise But Safety Concerns Raise Red Flags
- Hydrogen Gas Escapes Quickly From Corroding Magnesium Implants in Mice
- Alkaline Water and Aging in Fruit Flies
- Acidic Water Disinfectant May Harm Wound Healing in Surgery
- Hydrogen Water Shows Limited Effect on Muscle Loss in Rats
- Alkaline Ionized Water and Antioxidant Activity in Lab Tests
- Hydrogen Gas Fails to Protect Baby Rat Brains from Severe Oxygen Loss
- Hydrogen Water Improves Skin Drug Absorption in Lab Study
- Hydrogen Water Shows No Harmful Effects in Mouse Safety Study
- Electrolytic Water Cleaning Efficacy in Root Canals in Lab Tests
- Lab Study on How Hydrogen Water Works as an Antioxidant
- Highly Alkaline Water Stunts Growth in Rats Despite No Tissue Damage
- Alkaline Water During Pregnancy Increased Offspring Weight in Rats
- Alkaline Water Damages Heart Muscle in Pregnant Rats
- Alkaline Water Damages Heart Muscle in Rat Study
- Alkaline Water Shows Heart Risks in Rat Study
- Decompression Comparison of Helium and Hydrogen in Rats
- How Your Gut Produces and Uses Hydrogen Gas from Food
- Hydrogen Gas Solubility in Lab Blood and Muscle Tissue
- Hyperbaric Hydrogen Shows No Effect on Cancer Growth in Mice
- How Fast Hydrogen Gas Moves Through Muscle Tissue in Rats
- Inert Gas Solubility in Lab Rat Muscle Tissue
- How Your Gut Bacteria Naturally Produce Hydrogen Gas