Circadian RhythmsNCT06296823
Biomarkers for Peripheral Circadian Clocks in Humans
A study testing Simulated jetlag protocol in people with Circadian Rhythms, run by University of Colorado, Boulder at 1 site in United States.
Trial summary
The purpose of this project is to improve our understanding of peripheral circadian rhythms in humans. Circadian clocks are present in most tissues of the body with importance for optimal physiological function, health, and behavior. Read more about this study
- Who is it for?
- Ages 17 to 35 yearsHealthy volunteers can take part
- Conditions the study is for
- Circadian Rhythms
- What is being tested?
- Simulated jetlag protocol
- Type of treatment
- Lifestyle or therapy programme
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 14 participants
- Where
- 1 siteUnited States
- Study dates
- 1 Sep 2023to 31 Aug 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 17 to 35 years
- All sexes
- Healthy volunteers accepted
- Child, Adult
Who may be able to join
- 1) 17-35 years old 2) English speaking 3) Healthy 5) Altitude history: Currently residing at Denver altitude or higher
Who cannot join
- 1. Any medical, psychiatric, or sleep disorder.
Trial locations and contacts
1 site in 1 country. Contact the study team or a site near you to ask about taking part.
United States1 site, 1 recruiting
- Recruiting
Sleep and Chronobiology Laboratory
Boulder, Colorado, 80303
Kenneth Wright, 303-735-1923, sleep.study@colorado.edu
About this study
The purpose of this project is to improve our understanding of peripheral circadian rhythms in humans. Circadian clocks are present in most tissues of the body with importance for optimal physiological function, health, and behavior. This project will utilize simulated jetlag protocols to systematically test novel hypotheses about the regulation of peripheral circadian rhythms in humans. Specifically, we will examine how changes in the time of when we are exposed to light and the timing of when we eat impacts proteins in the blood and saliva that represent rhythms from clocks in the brain (e.g., rhythms of the hormones melatonin and cortisol coordinated by the brain) and rhythms from clocks in body tissues (e.g., proteins made by immune and bone cells, and cells in the stomach and liver). We also aim to discover new blood-based biomarkers of peripheral rhythms in humans. We anticipate our findings will be the first step in developing novel circadian based treatments for aligning peripheral clocks under conditions such as jetlag, and for developing novel circadian biomarkers that will advance our scientific understanding of circadian rhythms.
Read the detailed description
Visit 1: Participants who meet pre-screen/initial inclusion criteria will be consented at Visit 1, complete additional questionnaires and interviews to assess inclusion/exclusion criteria, and we will collect descriptive data as well as have our clinical psychologist perform a clinical interview.
Visit 2: Participants will undergo medical screening at the Clinical Translational Research Center at the University of Colorado Boulder (UCB-CTRC) to determine health status.
Visits 3 \& 6: Participants will be asked to maintain a regular ~8h sleep-wake schedule for two weeks prior to Visits 5 and 8. Participants will wear a wrist activity, skin temperature, and light exposure recorder. Participants will be asked to remain in the local time zone during ambulatory recording procedures and be asked to keep their typical schedules (e.g., not stay up all night for work or social events and not reside in a new place different from their place of residence).
Visit 4 \& 7: Participants will come to the laboratory on days 11 and 39, where qualified staff will apply a Continuous Glucose Monitoring (CGM) sensor to be worn for ~3 days at home and will continue in the laboratory. For the three days leading up to the study isocaloric meals including breakfast, lunch, and dinner will be provided. Participants will be asked to consume these energy balanced research diets (no caffeine) and meal timing will be scheduled (breakfast ~30 min, lunch ~5h, and dinner ~10h after awakening,). Exercise will be proscribed for these 3-days prior to the in-lab study.
Visits 5 \& 8: Participants will be randomized to condition order using an ABBA design (i.e., randomized into one of the two experimental conditions first in a crossover design: 3-days bright light exposure or 3-days of earlier timed meals). Both conditions are tested under an advanced sleep-wake schedule equivalent to traveling 5 time zones east. All participants will complete both conditions. On the second visit, participants will be tested in the other condition. Participants will live in the laboratory for 7.7 days each visit.
- Conditions
- Circadian Rhythms
- Being tested
- Simulated jetlag protocol
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Simulated jetlag protocolBehavioural
16 hours of wakefulness and an 8 hour scheduled sleep opportunity in a simulated jetlag protocol where you will go to bed and awaken earlier than usual.
| Study group | Role | What they receive |
|---|---|---|
| Meal timing | Experimental | Three days of meals, bedtimes and wake times scheduled to occur 5h earlier. Receives: Behavioral: Simulated jetlag protocol |
| Bright light | Experimental | Three days of exposure to bright light of ~3,000 lux, which is less than one-third the brightness of a sunrise or sunset (timed to start earlier by 1h each day) with scheduled bed and wake times timed 5h earlier. Receives: Behavioral: Simulated jetlag protocol |
What is being measured
The primary outcome is the main question the study is designed to answer.
PYY
Appetitive hormone-promotes satiety
Measured: hourly for up to 25 hours on two occasions
Ghrelin
Appetitive hormone-promotes food intake
Measured: hourly for up to 25 hours on two occasions
Leptin
Appetitive hormone-promotes satiety
Measured: hourly for up to 25 hours on two occasions
CRP
Acute phase response/also marker of inflammation
Measured: hourly for up to 25 hours on two occasions
OMD
Biomineralization
Measured: hourly for up to 25 hours on two occasions
PAI-1
Inhibitor of fibrinolysis
Measured: hourly for up to 25 hours on two occasions
IgE
Immune responses to parasites and allergens
Measured: hourly for up to 25 hours on two occasions
CCL18
Chemotaxis / immune cell trafficking
Measured: hourly for up to 25 hours on two occasions
PTH
Serum calcium homeostasis
Measured: hourly for up to 25 hours on two occasions
Secondary outcomes (3)
Glucose
Blood sugar
Measured: continuously for up to 35 hours on two occasions
Insulin
hormone that helps regulated blood glucose levels
Measured: hourly for up to 25 hours on two occasions
Proteomics
proteins
Measured: hourly for up to 25 hours on two occasions
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted6 Mar 2024
- Study start1 Sep 2023
- Primary completion31 Aug 2027 (estimated)
- Study completion31 Aug 2027 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Circadian RhythmsStudies 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
- None (open label)
- Enrolment
- 14 participants (estimated)
Sponsor and investigators
- Lead sponsor
- University of Colorado, Boulder
- Sponsor type
- University, hospital or other
- Collaborators
- University of Colorado, Denver
- Responsible party
- Principal investigator, Kenneth Wright, University of Colorado, Boulder
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT06296823
- Sponsor's protocol ID
- 22-0466
- Status last verified
- Jun 2026
- First submitted
- 29 Feb 2024
- Last updated
- 17 Jun 2026
- Results posted
- No
- Data monitoring committee
- Yes
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- Yes: Any data generated from the proposed work that is presented in a peer reviewed journal will be de-identified. Other data that is presented in a peer reviewed journal will be archived indefinitely and made available upon request. Microbiome data will be deposited in the International Nucleotide Sequence Database Collaboration www.insdc.org/ and is already deposited in Qiita http://qiita.microbio.me Metabolomics data will be deposited in Global Natural Products Social (GNPS) molecular networking http://gnps.ucsd.edu
Study at a glance
From the registry record, last updated by the sponsor on 17 Jun 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Biomarkers for Peripheral Circadian Clocks in Humans
- ClinicalTrials.gov ID
- NCT06296823
- Acronym / sponsor ID
- 22-0466
- Conditions
- Circadian Rhythms
- Study type
- Interventional
- Recruitment status
- Recruiting
- Enrolment
- 14 participants (estimated)
- Lead sponsor
- University of Colorado, BoulderUniversity, hospital or other
- Collaborators
- University of Colorado, Denver
- Study start
- 1 Sep 2023 (actual)
- Primary completion
- 31 Aug 2027 (estimated)
- Study completion
- 31 Aug 2027 (estimated)
- First posted
- 6 Mar 2024 (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.
The purpose of this project is to improve our understanding of peripheral circadian rhythms in humans. Circadian clocks are present in most tissues of the body with importance for optimal physiological function, health, and behavior. This project will utilize simulated jetlag protocols to systematically test novel hypotheses about the regulation of peripheral circadian rhythms in humans. Specifically, we will examine how changes in the time of when we are exposed to light and the timing of when we eat impacts proteins in the blood and saliva that represent rhythms from clocks in the brain (e.g., rhythms of the hormones melatonin and cortisol coordinated by the brain) and rhythms from clocks in body tissues (e.g., proteins made by immune and bone cells, and cells in the stomach and liver). We also aim to discover new blood-based biomarkers of peripheral rhythms in humans. We anticipate our findings will be the first step in developing novel circadian based treatments for aligning peripheral clocks under conditions such as jetlag, and for developing novel circadian biomarkers that will advance our scientific understanding of circadian rhythms.
Detailed description
Visit 1: Participants who meet pre-screen/initial inclusion criteria will be consented at Visit 1, complete additional questionnaires and interviews to assess inclusion/exclusion criteria, and we will collect descriptive data as well as have our clinical psychologist perform a clinical interview.
Visit 2: Participants will undergo medical screening at the Clinical Translational Research Center at the University of Colorado Boulder (UCB-CTRC) to determine health status.
Visits 3 \& 6: Participants will be asked to maintain a regular ~8h sleep-wake schedule for two weeks prior to Visits 5 and 8. Participants will wear a wrist activity, skin temperature, and light exposure recorder. Participants will be asked to remain in the local time zone during ambulatory recording procedures and be asked to keep their typical schedules (e.g., not stay up all night for work or social events and not reside in a new place different from their place of residence).
Visit 4 \& 7: Participants will come to the laboratory on days 11 and 39, where qualified staff will apply a Continuous Glucose Monitoring (CGM) sensor to be worn for ~3 days at home and will continue in the laboratory. For the three days leading up to the study isocaloric meals including breakfast, lunch, and dinner will be provided. Participants will be asked to consume these energy balanced research diets (no caffeine) and meal timing will be scheduled (breakfast ~30 min, lunch ~5h, and dinner ~10h after awakening,). Exercise will be proscribed for these 3-days prior to the in-lab study.
Visits 5 \& 8: Participants will be randomized to condition order using an ABBA design (i.e., randomized into one of the two experimental conditions first in a crossover design: 3-days bright light exposure or 3-days of earlier timed meals). Both conditions are tested under an advanced sleep-wake schedule equivalent to traveling 5 time zones east. All participants will complete both conditions. On the second visit, participants will be tested in the other condition. Participants will live in the laboratory for 7.7 days each visit.
Study design
- Primary purpose
- Basic science
- Allocation
- Randomised
- Intervention model
- Crossover
- Masking
- None (open label)
- Number of arms
- 2
| Arm | Type | Receives |
|---|---|---|
| Meal timing | Experimental | Behavioral: Simulated jetlag protocolThree days of meals, bedtimes and wake times scheduled to occur 5h earlier. |
| Bright light | Experimental | Behavioral: Simulated jetlag protocolThree days of exposure to bright light of ~3,000 lux, which is less than one-third the brightness of a sunrise or sunset (timed to start earlier by 1h each day) with scheduled bed and wake times timed 5h earlier. |
Who may qualify
- Ages
- 17 to 35 years
- Sex
- All
- Healthy volunteers
- Accepted
- Age groups
- Child, Adult
Key inclusion criteria (1 listed)
- 1) 17-35 years old 2) English speaking 3) Healthy 5) Altitude history: Currently residing at Denver altitude or higher
Key exclusion criteria (1 listed)
- 1. Any medical, psychiatric, or sleep disorder.
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 |
|---|---|---|
| Simulated jetlag protocol16 hours of wakefulness and an 8 hour scheduled sleep opportunity in a simulated jetlag protocol where you will go to bed and awaken earlier than usual. | Behavioural | Bright light, Meal timing |
Primary outcome
PYY
Time frame: hourly for up to 25 hours on two occasions
Appetitive hormone-promotes satiety
Ghrelin
Time frame: hourly for up to 25 hours on two occasions
Appetitive hormone-promotes food intake
Leptin
Time frame: hourly for up to 25 hours on two occasions
Appetitive hormone-promotes satiety
CRP
Time frame: hourly for up to 25 hours on two occasions
Acute phase response/also marker of inflammation
OMD
Time frame: hourly for up to 25 hours on two occasions
Biomineralization
PAI-1
Time frame: hourly for up to 25 hours on two occasions
Inhibitor of fibrinolysis
IgE
Time frame: hourly for up to 25 hours on two occasions
Immune responses to parasites and allergens
CCL18
Time frame: hourly for up to 25 hours on two occasions
Chemotaxis / immune cell trafficking
PTH
Time frame: hourly for up to 25 hours on two occasions
Serum calcium homeostasis
3 secondary outcomes
Glucose
Time frame: continuously for up to 35 hours on two occasions
Insulin
Time frame: hourly for up to 25 hours on two occasions
Proteomics
Time frame: hourly for up to 25 hours on two occasions
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 17 Jun 2026.
- Individual participant dataSharing planned: Yes. Any data generated from the proposed work that is presented in a peer reviewed journal will be de-identified. Other data that is presented in a peer reviewed journal will be archived indefinitely and made available upon request. Microbiome data will be deposited in the International Nucleotide Sequence Database Collaboration www.insdc.org/ and is already deposited in Qiita http://qiita.microbio.me Metabolomics data will be deposited in Global Natural Products Social (GNPS) molecular networking http://gnps.ucsd.edu
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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.
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing Simulated jetlag protocol in people with Circadian Rhythms, run by University of Colorado, Boulder at 1 site in United States.
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 1 inclusion and 1 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: looking for participants now, as of the sponsor's last update on 17 Jun 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?
Contact Kenneth Wright, PhD (303-735-1923, sleep.study@colorado.edu), or a site near the patient. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
PYY (time frame: hourly for up to 25 hours on two occasions). The study lists 9 primary outcomes in all. It is what the study was designed to measure, not a finding.
Where can I read the original study information?
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 17 Jun 2026.