Insulin ResistanceNCT04168372

Fructose: Substrate, Stimulus, or Both?

A study testing High fructose, fructose labeled meal, High fructose, pyruvate labeled meal and Low fructose, fructose labeled meal in people with Insulin Resistance and Insulin Sensitivity, run by Touro University, California at 1 site in United States.

Active, not recruiting

Under way, not looking for participants. Everyone needed has enrolled. The study is still running.

Official record

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Trial summary

This objective of this study is to use sensitive methodology under controlled conditions to investigate the mechanisms by which fructose consumption contributes to excess fatty acid synthesis and elevations in blood glucose levels following consumption of meals containing fructose. Read more about this study

Who is it for?: Ages 20 to 55 yearsHealthy volunteers can take part
Conditions the study is for: Insulin Resistance, Insulin Sensitivity, Pre Diabetes
What is being tested?: High fructose, fructose labeled meal, High fructose, pyruvate labeled meal and Low fructose, fructose labeled meal
Could I receive a placebo?: No, everyone receives an active treatment
How many people: 35 participants
Where: 1 siteUnited States
Study dates: 15 Sep 2019to 20 Jul 2027
Phase: Interventional
Are there results?: Not yet: the study is under way

Key requirements

Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.

Ages 20 to 55 years
All sexes
Healthy volunteers accepted
Adult

Who may be able to join

Body Mass Index 22 to 35 kg/m2
Prediabetic (HbA1c 5.7% to 6.5%) or hyperinsulinemic (fasting insulin ≥12 µIU/mL) but non-diabetic (fasting glucose <126mg/dL and HbA1c < 6.5%) ; or normal control (fasting insulin <10 µIU/mL, fasting glucose <100 mg/dL, and HbA1c < 5.7%)

Who cannot join

Pregnancy or lactation within the past six months
Type 1 or 2 diabetes mellitus
History of liver disease or aspartate aminotransferase (AST) and alanine aminotransferase (ALT) 2x the upper limit of normal (ULN);
Fasting triglyceride or total cholesterol levels above 95th percentile for age and sex;
Hemoglobin or hematocrit below the lower limit of normal for sex;
Report of hepatitis or HIV infection;

Show all 11Show fewer

History of cancer, use of any anti-diabetic medications or hypolipidemic agents in the past six months;
History of surgical procedure for obesity;
Self-reported change in body weight >5% in the past six months;
History of other conditions known to affect insulin sensitivity and lipid metabolism;
Known intolerance to acetaminophen or components of the liquid test meals.

Trial locations and contacts

1 site in 1 country.

United States1 site

Touro University California
Vallejo, California, 94592

Other trials in United States

About this study

Conditions: Insulin Resistance, Insulin Sensitivity, Pre Diabetes
Being tested: High fructose, fructose labeled meal, High fructose, pyruvate labeled meal, Low fructose, fructose labeled meal, Low fructose, pyruvate labeled meal
Keywords: Fructose, Glucose, Lipogenesis
Medical subject headings: Insulin Resistance, Glucose Intolerance

What participants receive

What participants receive. In a randomised study each person is assigned to one group by chance.

High fructose, fructose labeled mealOther
Liquid meal containing high fructose (16% of energy), labeled with 2-13C fructose
High fructose, pyruvate labeled mealOther
Liquid meal containing high fructose (16% of energy), labeled with 2-13C pyruvate
Low fructose, fructose labeled mealOther
Liquid meals containing low fructose (6% of energy), labeled with 2-13C fructose
Low fructose, pyruvate labeled mealOther
Liquid meal containing low fructose (6% of energy), labeled with 2-13C pyruvate

Study groups in NCT04168372
Study group	Role	What they receive
High fructose meal, with fructose label	Experimental	2-13C fructose incorporated into a meal with high fructose content Receives: Other: High fructose, fructose labeled meal
High fructose meal, with pyruvate label	Experimental	2-13C pyruvate incorporated into a meal with high fructose content Receives: Other: High fructose, pyruvate labeled meal
Low fructose meal, with fructose label	Experimental	2-13C fructose incorporated into a meal with low fructose content Receives: Other: Low fructose, fructose labeled meal
Low fructose meal, with pyruvate label	Experimental	2-13C pyruvate incorporated into a meal with low fructose content Receives: Other: Low fructose, pyruvate labeled meal

What is being measured

The primary outcome is the main question the study is designed to answer.

Hepatic fractional de novo lipogenesis in triglyceride rich lipoprotein (TRL)
Measured by the detection of 13C carbons in TRL-palmitate from administered 13C labeled pyruvate or 13C labeled fructose.
Measured: 6 hours
Rate of appearance of UDP-glucose
An estimate of hepatic glycogen flux measured by administration of D1 galactose and acetaminophen
Measured: 6 hours
Rate of appearance of blood glucose from gluconeogenesis
Measured by the dilution method of labeled glucose
Measured: 6 hours

Secondary outcomes (9)

Serum triglyceride concentration
Fasting and postprandial serum triglyceride levels
Measured: 6 hours
Serum glucose concentration
Fasting and postprandial serum triglyceride levels
Measured: 6 hours
Serum lactate concentration
Fasting and postprandial serum lactate levels
Measured: 6 hours
Serum insulin concentration
Fasting and postprandial insulin levels
Measured: 6 hours
Serum free fatty acid concentration
Fasting and postprandial fatty acid levels
Measured: 6 hours
Enteral (chylomicron) fractional de novo lipogenesis (DNL)
Measured by the detection of 13C carbons in chylomicron-palmitate from administered 13C labeled pyruvate or 13C labeled fructose.
Measured: 6 hours
Hepatic (VLDL) fractional de novo lipogenesis (DNL)
Measured by the detection of 13C carbons in VLDL-palmitate from administered 13C labeled pyruvate or 13C labeled fructose.
Measured: 6 hours
Extrasplanchnic fructose
Calculated using total plasma fructose, plasma 2-13C fructose enrichment, and endogenous fructose production
Measured: 6 hours
Whole body fructose oxidation
Measured by 13C atom % excess in exhaled breath, and VCO2 by indirect calorimetry
Measured: 6 hours

Timeline

From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.

15 Sep 201920 Jul 2027

First posted19 Nov 2019
Study start15 Sep 2019
Primary completion31 Dec 2026 (estimated)
Study completion20 Jul 2027 (estimated)

Resources

Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
Other trials for Insulin ResistanceStudies of the same condition, open and under way.
What the trial phases meanHow a treatment moves from first tests in people to approval.

More details

For doctors and researchers: how the study is designed, who runs it, and its registry IDs.

Study design

Study type: Interventional
Phase: Phase N/A
Primary purpose: Basic science
Allocation: Randomised
Intervention model: Crossover
Masking: Triple blind
Who is masked: Participant, Investigator, Outcomes assessor
Enrolment: 35 participants (actual)

IDs, dates and publications

ClinicalTrials.gov ID: NCT04168372
Sponsor's protocol ID: M-3018
Status last verified: Jul 2026
First submitted: 14 Nov 2019
Last updated: 10 Jul 2026
Results posted: No
Data monitoring committee: No
FDA-regulated drug: No
FDA-regulated device: No

Want to know more?

The sponsor has not listed a contact. The official record may have more details.

Talk to your doctor first and take this page with you. Only the study team can confirm whether you can join.

Questions to ask the study team

What is the study trying to find out?
What would I need to do, and how often would I visit?
Could I receive a placebo instead of the treatment?
What are the possible risks and benefits for me?
Will it cost me anything? Are travel or time paid for?
Can I keep seeing my own doctor during the study?
What happens when the study ends?

See locations

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All Insulin Resistance trials

Study at a glance

From the registry record, last updated by the sponsor on 10 Jul 2026. Recruitment status is as the sponsor reported it: confirm with the study team.

Official title: Fructose: Substrate, Stimulus, or Both?
ClinicalTrials.gov ID: NCT04168372
Acronym / sponsor ID: M-3018
Conditions: Insulin Resistance, Insulin Sensitivity, Pre Diabetes
Keywords: Fructose, Glucose, Lipogenesis
Study type: Interventional
Recruitment status: Active, not recruiting
Enrolment: 35 participants (actual)
Lead sponsor: Touro University, CaliforniaUniversity, hospital or other
Study start: 15 Sep 2019 (actual)
Primary completion: 31 Dec 2026 (estimated)
Study completion: 20 Jul 2027 (estimated)
First posted: 19 Nov 2019 (actual)
Results: Not posted in the source record

Clinical summary

The research question as the sponsor registered it. This describes what the study plans to test, not what it found.

Study design

Primary purpose: Basic science
Allocation: Randomised
Intervention model: Crossover
Masking: Triple blind (participant, investigator, outcomes assessor)
Number of arms: 4

Arm	Type	Receives
High fructose meal, with fructose label	Experimental	Other: High fructose, fructose labeled meal2-13C fructose incorporated into a meal with high fructose content
High fructose meal, with pyruvate label	Experimental	Other: High fructose, pyruvate labeled meal2-13C pyruvate incorporated into a meal with high fructose content
Low fructose meal, with fructose label	Experimental	Other: Low fructose, fructose labeled meal2-13C fructose incorporated into a meal with low fructose content
Low fructose meal, with pyruvate label	Experimental	Other: Low fructose, pyruvate labeled meal2-13C pyruvate incorporated into a meal with low fructose content

Who may qualify

Ages: 20 to 55 years
Sex: All
Healthy volunteers: Accepted
Age groups: Adult

Key inclusion criteria (2 listed)

Body Mass Index 22 to 35 kg/m2
Prediabetic (HbA1c 5.7% to 6.5%) or hyperinsulinemic (fasting insulin ≥12 µIU/mL) but non-diabetic (fasting glucose <126mg/dL and HbA1c < 6.5%) ; or normal control (fasting insulin <10 µIU/mL, fasting glucose <100 mg/dL, and HbA1c < 5.7%)

Key exclusion criteria (11 listed)

Pregnancy or lactation within the past six months
Type 1 or 2 diabetes mellitus
History of liver disease or aspartate aminotransferase (AST) and alanine aminotransferase (ALT) 2x the upper limit of normal (ULN);
Fasting triglyceride or total cholesterol levels above 95th percentile for age and sex;
Hemoglobin or hematocrit below the lower limit of normal for sex;

Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.

Interventions

Intervention	Type	Arms
High fructose, fructose labeled mealLiquid meal containing high fructose (16% of energy), labeled with 2-13C fructose	Other	High fructose meal, with fructose label
High fructose, pyruvate labeled mealLiquid meal containing high fructose (16% of energy), labeled with 2-13C pyruvate	Other	High fructose meal, with pyruvate label
Low fructose, fructose labeled mealLiquid meals containing low fructose (6% of energy), labeled with 2-13C fructose	Other	Low fructose meal, with fructose label
Low fructose, pyruvate labeled mealLiquid meal containing low fructose (6% of energy), labeled with 2-13C pyruvate	Other	Low fructose meal, with pyruvate label

Primary outcome

Hepatic fractional de novo lipogenesis in triglyceride rich lipoprotein (TRL)
Time frame: 6 hours
Measured by the detection of 13C carbons in TRL-palmitate from administered 13C labeled pyruvate or 13C labeled fructose.
Rate of appearance of UDP-glucose
Time frame: 6 hours
An estimate of hepatic glycogen flux measured by administration of D1 galactose and acetaminophen
Rate of appearance of blood glucose from gluconeogenesis
Time frame: 6 hours
Measured by the dilution method of labeled glucose

9 secondary outcomes

Serum triglyceride concentration
Time frame: 6 hours
Serum glucose concentration
Time frame: 6 hours
Serum lactate concentration
Time frame: 6 hours
Serum insulin concentration
Time frame: 6 hours
Serum free fatty acid concentration
Time frame: 6 hours
Enteral (chylomicron) fractional de novo lipogenesis (DNL)
Time frame: 6 hours
Hepatic (VLDL) fractional de novo lipogenesis (DNL)
Time frame: 6 hours
Extrasplanchnic fructose
Time frame: 6 hours
Whole body fructose oxidation
Time frame: 6 hours

Results and safety

This study is still under way. Results are not available in the source record yet.

Research links

Official record on ClinicalTrials.govLast updated by the sponsor 10 Jul 2026.

Related trials for Insulin Resistance

Not yet recruitingPhase 2
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RecruitingObservational study
Long-Term Follow-Up of Survivors of Pediatric Cushing Disease
Cushing Disease
Recruiting
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Recruiting
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Study of the Effect of Innate on the Inflammatory Response to Endotoxin
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Referral and contact

AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.

Jean-Marc Schwarz, PhD principal investigator

Touro University, California

1 site in 1 country: see every site and its status.

Questions about this trial

What is this clinical trial studying?

The full registered description is in the About this study section and the official record.

Who may be eligible to take part?

The sponsor lists 2 inclusion and 11 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.

Is this clinical trial currently recruiting?

The record says: under way, not looking for participants, as of the sponsor's last update on 10 Jul 2026. Status can change between updates, so confirm with the study contact before making plans.

Where is the study taking place?

The record lists 1 site in United States. Whether a site is taking part right now should be confirmed with that site. See every site.

What are the possible benefits and risks?

They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.

Are results available for this study?

This study is still under way. Results are not available in the source record yet.

How can a doctor refer a patient or contact the research team?

The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.

What does the primary outcome measure?

Hepatic fractional de novo lipogenesis in triglyceride rich lipoprotein (TRL) (time frame: 6 hours). The study lists 3 primary outcomes in all. It is what the study was designed to measure, not a finding.

Where can I read the original study information?

On the ClinicalTrials.gov record for NCT04168372.

Does a listing mean the treatment is approved or proven to work?

No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.

How often is this information updated?

AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 10 Jul 2026.