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Clinical Research Directory

Browse clinical research sites, groups, and studies.

929 clinical studies listed.

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Healthy

Tundra lists 929 Healthy clinical trials. Each listing includes eligibility criteria, study locations, and direct links to research sites in the Tundra directory.

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RECRUITING

NCT06104670

The Effect of Synaquell™ in Contact Sport Athletes

This research is being done to investigate the dietary supplement, Synaquell (TM), for effects on brain function in youth contact sport athletes.

Gender: All

Ages: 13 Years - 19 Years

Updated: 2026-05-29

1 state

Healthy
RECRUITING

NCT07160244

BEATRIX: A Study to Learn About a Group B Streptococcus Vaccine in Healthy Pregnant Women and Their Babies

BEATRIX (group B strEptococcus mATeRnal and Infant VaX study) The purpose of this study is to learn about the safety and how the group B streptococcus (GBS) vaccine works in pregnant women and their babies. This study is seeking healthy pregnant participants: * aged 49 or younger who can join. * between 24 and 36 weeks of gestation ("Gestational age" is a medical term used to describe how far along your pregnancy is) * had a fetal ultrasound examination performed with no major fetal abnormalities observed * documented negative for HIV, syphilis and Hepatitis B All participants in this study will receive only 1 shot in an arm. This could either be a group B streptococcus 6-valent polysaccharide conjugate vaccine (GBS6) or placebo. Placebo is an inactive substance used in the study for comparison purposes; in this study, the placebo injection will be saline (saltwater). The pregnant participants may take part in this study for a maximum of 14 months (6 months after delivery) , and their babies for about 12 months after they are born. The pregnant participants will need to visit the research site at least 3 to 4 times with some visits permitted to occur over the telephone. A subset of infants will be asked to take part in the study for up to 19 months. The subset will receive diphtheria toxoid-containing vaccine and/or pneumococcal vaccine following each country's standard immunization plan and have blood drawn 1 month after completion of the primary and/or toddler (booster) doses.

Gender: All

Ages: 1 Day - 49 Years

Updated: 2026-05-29

66 states

Healthy
COMPLETED

NCT01866852

Expansion of Childhood Relationship Study to Young Adult Romantic Relationships

Background: \- An earlier study on child development focused on the relationship between children and their caregivers (usually mothers). It looked at how this relationship influenced children's social and mental development. It also studied how these children related with family members and friends. Researchers are now interested in expanding the study with the same group of children. They want to look at these children, who are now young adults, and focus on their current romantic relationships. This new study will look at how child development affects the formation of stable, mature romantic relationships in young adulthood. Original child study participants and their significant others will be included in the new study. Only participants who are living together with a partner will be studied. Objectives: \- To look at romantic partnerships in a childhood study s original participants and their significant others. Eligibility: * Participants of the 88-CH-32 study who are at least 18 years of age. * Significant others of the study participants who are at least 18 years of age. * Original participants and significant others must be cohabiting (living together). Design: * No screening tests will be required for this study. No study visits will be needed. Samples will not be collected. * Original study participants will fill out four online questionnaires. They will be on a National Institute of Child Health and Human Development (NICHHD) website. They will ask personal questions about relationships with the current romantic partner and other important people. The questions will take about 25 minutes to answer. * Significant others will fill out 13 online questionnaires. They will be on a NICHHD website. They will ask personal questions about the romantic partner and other important people. The questions will take about 1.5 hours to answer. * All participants will receive a small amount of money for completing the study.

Gender: All

Ages: 18 Years - 30 Years

Updated: 2026-05-29

1 state

Healthy
RECRUITING

NCT06989320

Endogenous Oxalate Synthesis in Idiopathic Calcium Oxalate Kidney Stone Disease

The goal of this clinical trial study is to test if patients with idiopathic calcium oxalate kidney stones have an increased production of oxalate by the body, which would lead to increased urinary excretion of oxalate. The study will recruit adult patients with a history of calcium oxalate kidney stones and healthy volunteers without kidney stones. Participants will ingest fixed diets containing low amounts of oxalate for 5 days ingest a soluble form of glycolate and vitamin C collect urine, blood, stool during the dietary and oral dosing portions of the study and also collect breath sample during the oral glycolate test

Gender: All

Ages: 18 Years - 80 Years

Updated: 2026-05-29

2 states

Kidney Stones
Kidney Calculi
Urolithiasis
+6
RECRUITING

NCT00004577

Study of New Magnetic Resonance Imaging Methods of the Brain

The purpose of this investigation is to develop improved magnetic resonance imaging (MRI) techniques and hardware for studying brain function. MRI is a diagnostic tool that provides information about brain chemistry and physiology. This study will evaluate new MRI methods for monitoring blood flow to regions of the brain in response to simple tasks. The MRI machine used in this study is more powerful than those in most hospitals, permitting a higher visual resolution. Normal healthy volunteers over 18 years old may be eligible for this study. Candidates will be screened with a medical history and questionnaire, and a neurological examination. Study participants will have a yearly MRI scan. For this procedure, the subject lies on a stretcher that is moved into a donut-shaped machine with a strong magnetic field. A lightweight circular or rectangular coil-a device that improves the quality of the images-may be placed on the head. The scan time varies from 20 minutes to 3 hours; most scans last between 45 and 90 minutes. During the scan, the subject may perform simple tasks, such as listening to tapes, tapping a finger, moving a hand, watching a screen, or smelling a fragrance. More complex tasks may require thinking about tones or pictures and responding to them by pressing buttons. Information from this study will be used to develop better imaging methods that will, in turn, permit a greater understanding of normal and abnormal brain behaviors. ...

Gender: All

Ages: 18 Years - 120 Years

Updated: 2026-05-29

1 state

Healthy Volunteer
Magnetic Resonance Imaging
Healthy
+3
NOT YET RECRUITING

NCT03590821

Timed Aspirin Chronobiome Study

To determine whether timed administration of aspirin ameliorates the effects of celecoxib on blood pressure.

Gender: All

Ages: 18 Years - Any

Updated: 2026-05-29

1 state

Healthy
RECRUITING

NCT06426498

tFUS Induced Transient Scotoma for Individual Dosing

The purposes of this research study is to: 1. Develop a technique of transcranial Focused Ultrasound Stimulation (tFUS) where meaningful effects on the brain can be easily measured. 2. Use this technique to measure threshold for effective tFUS in individuals. 3. Determine whether disruption of conscious visual detection, versus non-conscious visually-guided behavior have different thresholds for disruption with tFUS.

Gender: All

Ages: 18 Years - 70 Years

Updated: 2026-05-29

1 state

Healthy
COMPLETED

NCT06805240

The ILLUMINATE Study

The research study will be conducted to obtain baseline, or "normative" information to compare an air charged HRAM catheter to traditional solid catheter measures using the IAPWG standardized testing protocol and London classification.

Gender: All

Ages: 18 Years - 65 Years

Updated: 2026-05-29

3 states

Healthy
RECRUITING

NCT06707207

Predicting Future Errors During Skill Performance

Background: Many tasks people do every day require a series of individual movements. Control over these movements is called motor skills. But even highly skilled people can make mistakes. Researchers have found that they can predict when a person will make a mistake 0.1 second before it happens. Now, they want to find out if they can increase that time up to 1 second-long enough to warn the person and prevent the mistake. Objective: To see if motor skill errors can be detected up to 1 second before they occur. Eligibility: Right-handed healthy adults aged 18 to 35. Design: Participants will have 2 to 5 study visits. Each visit will be 1 to 2 hours. They will have a physical and neurological exam. They will have 1 or 2 magnetic resonance imaging (MRI) scans. They will lie on a table that slides into a large cylinder. The MRI uses strong magnets to capture images of the inside of the body, including the brain. They will have another scan, called magnetoencephalography (MEG). Small metal disks attached to wires will be taped to their head. Participants will sit in a padded chair with their head inside of a helmet. The helmet will not cover their eyes or face. Participants will perform a series of typing tasks on a keyboard. They will have short breaks between each round. Their head movements will be tracked, and their eye and finger movements will be videotaped.

Gender: All

Ages: 18 Years - 35 Years

Updated: 2026-05-29

1 state

Healthy
ACTIVE NOT RECRUITING

NCT04437225

Renal Metabolism of Glycolate to Oxalate

This study will determine the contribution of glycolate metabolism to urinary oxalate excretion in healthy subjects, using carbon 13 isotope glycolate tracer technique and a low-oxalate controlled diet.

Gender: All

Ages: 18 Years - 75 Years

Updated: 2026-05-29

1 state

Healthy
RECRUITING

NCT07169630

PET Imaging of Phosphodiesterase-4 (PDE4) in Volunteers With Alzheimer Disease (AD) or Mild Cognitive Impairment (MCI)

Background: About 5 million adults in the United States have age-related brain disorders. These include Alzheimer disease (AD), mild cognitive impairment (MCI), and other dementias. The number of people with these disorders will likely increase as the population ages and life span increases. Inflammation is thought to play a role in AD and MCI. Researchers want to know if an enzyme called PDE4B increases inflammation in people with AD or MCI. Objective: To test whether medical imaging using a new radiotracer (\[18F\]PF-06445974) can measure PDE4B in the brains of people with AD or MCI. Eligibility: People aged 50 years and older with AD or MCI. Healthy volunteers are also needed. Design: Participants will have up to 5 clinic visits with 3 imaging scans of the brain. They will have be screened. They will have a physical exam with blood tests. This will include tests of their heart and nerve function, including memory. Participants will have 2 positron emission tomography (PET) scans. One will use a standard radiotracer. The other will use the study radiotracer. They will receive each tracer through a tube attached to a needle inserted into a vein. During the scan with the study tracer, participants will have a second tube inserted into a vein in the wrist; this tube will be used to draw blood during the scan. Participants will lie on a bed that slides into a doughnut-shaped machine. These visits will take about 6 hours each. Participants will have 1 magnetic resonance imaging (MRI) scan. They will lie on a bed that slides into a cylinder. This visit will take up to 2 hours....

Gender: All

Ages: 50 Years - 100 Years

Updated: 2026-05-29

1 state

Alzheimer s Disease
Mild Cognitive Impairment
Healthy
COMPLETED

NCT07044271

A Study of Multiple Olomorasib (LY3537982) Capsules in Healthy Participants

The main purpose of this study is to measure how much olomorasib gets into the bloodstream and how long it takes the body to get rid of it. Healthy participants will take olomorasib by mouth. The study will last about 7 weeks and will include 10 back-to-back overnight stays in the research center.

Gender: All

Ages: 18 Years - 55 Years

Updated: 2026-05-29

2 states

Healthy
COMPLETED

NCT05051566

A Multiple Dose Study of LY3502970 in Healthy Participants

The main purpose of this study is to assess how fast LY3502970 gets into the blood stream and how long it takes the body to remove it when administered in multiple oral doses as new formulation compared to that of reference LY3502970 formulation. Information about safety and tolerability will be collected. The study is open to healthy participants. The study is conducted in two parts and it will last up to about 6 months, inclusive of screening period.

Gender: All

Ages: 18 Years - 65 Years

Updated: 2026-05-29

Healthy
COMPLETED

NCT06570369

A Study to Explore the Effect of SP-624 on Brain Network Analytics in Healthy Adults and Adults With Major Depression

The main goal of this clinical trial is to learn if the active study drug (code name: SP-624) has any effect on the electrical activity of the brain in adult healthy volunteers and in adults with major depression. Another goal of the study is to learn if SP-624 improves memory and learning in adults with major depression. The study will also provide additional information on the safety of SP-624 and how well it is tolerated in adult healthy volunteers and adults with major depression. Researchers will compare SP-624 to a placebo (a look-alike substance that contains no drug) to see if SP-624 has any effect on study tests. Study participants will: Take capsules of study drug (SP-624 or a placebo) once daily for 2 weeks; visit the clinic at Screening, Day 1 (first dose of study drug), and Day 15 (last dose of study drug) for checkups and tests; and have phone call check-ups on Day 7 and about 1 week after the last dose of study drug.

Gender: All

Ages: 18 Years - 60 Years

Updated: 2026-05-28

2 states

Major Depressive Disorder
Depression
Healthy
RECRUITING

NCT05040204

The Effects of Dietary Supplementation on Serum Protein Glycosylation

Two randomized double-blind placebo-controlled clinical studies to assess the effects of dietary glycan monomer supplementation on the immune system, especially antibody glycosylation in healthy adults. Immune profiling and glycoproteomics will be performed on serum isolated at these same time points.

Gender: All

Ages: 18 Years - 45 Years

Updated: 2026-05-28

1 state

Healthy
RECRUITING

NCT06331546

Gut Oxalate Absorption in Calcium Oxalate Stone Disease

The goal of this clinical trial study is to test if patients with idiopathic calcium oxalate kidney stones have an increased absorption of dietary oxalate, which would lead to increased urinary excretion of oxalate. The study will recruit adult patients with a history of calcium oxalate kidney stones and healthy volunteers without kidney stones. Participants will * ingest fixed diets containing low and moderately high amounts of oxalate for 5 days at a time * ingest a soluble form of oxalate and sugar preparations to test gut permeability * collect urine, blood, stool and breath sample during the fixed diets and the soluble oxalate test

Gender: All

Ages: 18 Years - 70 Years

Updated: 2026-05-28

2 states

Kidney Stone
Kidney Calculi
Urolithiasis
+6
RECRUITING

NCT07023354

A Study to Test How BI 1291583 is Taken up in the Blood of People With and Without Liver Problems

This study is open to adults aged between 18 and 80 years of age with a body mass index (BMI) of 18.5 to 42 kg/m². People with or without liver problems can take part in the study. The purpose of this study is to find out how much of a medicine called BI 1291583 gets into the blood of people with and without liver problems. BI 1291583 is being developed to treat people with bronchiectasis, a chronic disease of the lungs. People living with this condition often also have liver problems. Therefore, it is important to find out whether liver problems influence the amount of BI 1291583 that gets into the blood. Study participants receive a single dose of BI 1291583 as a tablet taken by mouth. Participants are divided into 4 groups based on how well their liver works: 1 group without liver problems, and 3 groups with mild, moderate, and severe liver problems. Each participant without liver problems is matched with participants from the other groups based on factors such as age, sex, smoking habits, and body weight to ensure accurate comparisons. Participants are in the study for about 3 months. They stay for 3 days at the study site and also visit the study site up to 9 times. During these visits, the doctors collect information about participants' health. To assess the study endpoints, the doctors regularly take blood samples from the participants. The doctors regularly check participants' health and take note of any unwanted effects.

Gender: All

Ages: 18 Years - 80 Years

Updated: 2026-05-28

2 states

Healthy
Hepatic Impairment
COMPLETED

NCT02707042

Microbial, Immune, and Metabolic Perturbations by Antibiotics (MIME Study)

More than 250 million courses of antibiotics are prescribed annually in the ambulatory care setting in the United States alone, including more than 40 million in children under 18 years of age. The perception that antibiotic use has minimal attendant adverse side effects contributes to the over-utilization of antibiotics in clinical circumstances when they are not strictly indicated. We have learned much about the human microbiome. The emerging view is of profound life-long bi-directional interactions between our microbiota and our cells. Perturbations in the microbiota affect metabolic, immune, and cognitive physiology in experimental animal models. When a person takes an antibiotic, the antibiotic diffuses via the blood into all body compartments, selecting for resistance. We propose to examine the effects of two commonly used antibiotics (the beta-lactam, amoxicillin and the macrolide azithromycin) on human microbial populations and on metabolic and immune physiology, studying healthy human volunteers in a randomized controlled clinical trial at the NIH Clinical Center. Our hypothesis is that in addition to acutely perturbing the human microbiome, these agents will have measurable metabolic and immunologic effects, with residual effects in the weeks that follow. To test this hypothesis, we will assess the effects of a brief therapeutic course of antibiotics on microbiome and metagenome composition. After an initial evaluation period, antibiotics will be given for 7 days or 5 days (depending on the antibiotic), and there will be a post-treatment evaluation. A control group will receive no drug intervention. Specimens will be obtained from multiple sites at each of 10 time points occurring before, during, and after antibiotic administration, and used for estimating bacterial and fungal composition and gene content. We will also assess the effects of the antibiotic course on markers of innate and adaptive immunity as well as markers of metabolic and hormonal physiology. A subgroup of subjects will be studied in the clinical center metabolic chamber to assess 24-hour energy expenditure and its components (sleeping, diet-induced, and activity energy expenditure), as well as macronutrient oxidation rates (carbohydrate, fat, and protein), during 3 of the 10 study visits. In addition to the primary data analyses, we will build a model that integrates the temporal data to begin to understand the complex intertwined physiology between microbiome and host.

Gender: All

Ages: 18 Years - 49 Years

Updated: 2026-05-28

1 state

Normal Physiology
Healthy
RECRUITING

NCT06592261

Graded Insulin Suppression Test P&F

The goal of this study is to learn about how the hormone insulin controls blood sugar in a variety of people. The main question it aims to answer is about how much insulin the body actually needs to maintain a normal blood sugar level. Participants will be asked to come in for a one-day study visit in which they will undergo a "graded insulin suppression test" ("GIST"). The GIST involves intravenous (into the vein) infusions of octreotide, a medication that turns off the body's own production of insulin, as well as replacement of insulin at two different levels (low and high), with or without replacement of glucagon, and glucose (sugar). The study investigators will check blood sugar levels every few minutes during the procedure to determine the effect of the two different insulin levels. This study will evaluate the GIST in both healthy volunteers and those at higher risk for type 2 diabetes.

Gender: All

Ages: 18 Years - 65 Years

Updated: 2026-05-28

1 state

Insulin Resistance
Hyperinsulinemia
Obesity
+1
ACTIVE NOT RECRUITING

NCT07388667

A Clinical Study of MK-4082 in Healthy Overweight Participants (MK-4082-002)

Researchers are looking for new weight loss medicines for people with higher body weight. The study medicine, MK-4082, is different from similar weight loss medicines because people take it as a pill instead of an injection. Before giving a study medicine to people with a health condition, researchers first do studies to find a safe dose level (amount) of the study medicine that can be used in future studies. The goals of this study are to learn about: * The safety of MK-4082 and if people tolerate it * What happens to different MK-4082 dose levels in a person's body over time

Gender: All

Ages: 18 Years - 60 Years

Updated: 2026-05-28

4 states

Healthy
RECRUITING

NCT05748990

Does Abnormal Insulin Action in the Brain Underlie Cognitive and Metabolic Dysfunction in Schizophrenia

Cognitive impairment (such as challenges in thinking and memory) is a core aspect of schizophrenia (SCZ), contributing to disability and poor functional outcomes. Additionally, almost half of the patients with SCZ are obese, the prevalence of type 2 diabetes is 3-6 times higher, and life expectancy is lower by 15-20 years compared to the general population. This is relevant as metabolic syndrome and diabetes are both associated with worse cognition among SCZ patients. Recent work studying the relationships between metabolic health and cognition has encouraged a new way of thinking about SCZ as both a metabolic and cognitive disorder. Brain insulin is involved in several processes relevant to SCZ, and abnormal brain insulin action may help explain both cognitive and metabolic abnormalities in patients with SCZ, but this has not been examined previously. Glucose uptake in several brain regions relevant to SCZ has been shown to be partially dependent on insulin. Therefore, in this study, the researchers will measure glucose uptake in the brain using an 18F-fluorodeoxyglucose (\[18F\]-FDG) positron emission tomography (PET) scan after an intranasal insulin stimulus, and will compare this measure between patients with SCZ and healthy controls.

Gender: All

Ages: 17 Years - 45 Years

Updated: 2026-05-28

1 state

Schizophrenia
Healthy
ACTIVE NOT RECRUITING

NCT07530289

A Clinical Study of Ulonivirine (MK-8507) With Atorvastatin and Metformin in Healthy Adults (MK-8507-018)

Researchers want to learn about ulonivirine when given with atorvastatin and metformin in healthy people. The goal of this study is to compare the amount of atorvastatin and metformin in a person's body over time when given with and without ulonivirine.

Gender: All

Ages: 18 Years - 55 Years

Updated: 2026-05-28

1 state

Healthy
COMPLETED

NCT07232589

A Study of the Effect of Diltiazem on the Plasma Levels of Nemtabrutinib (MK-1026-022)

The goal of the study is to learn what happens to levels of nemtabrutinib (MK-1026) in a healthy person's body over time. Researchers will compare what happens to nemtabrutinib in the body when it is given with or without another medicine called diltiazem.

Gender: All

Ages: 18 Years - 55 Years

Updated: 2026-05-28

1 state

Healthy
RECRUITING

NCT07300280

A Clinical Trial of Enlicitide and Rosuvastatin in Healthy Adults (MK-0616-039)

This goal of this trial is to learn about two medicines, enlicitide and rosuvastatin, in healthy people. Researchers will compare the amounts of enlicitide and rosuvastatin in a person's body over time, when they are given as separate medicines and when they are combined into one tablet.

Gender: All

Ages: 18 Years - 55 Years

Updated: 2026-05-28

1 state

Healthy