HealthyPhase 4NCT04831398
The Effects of Acute Melatonin Supplementation on Cardiovascular Responses to Sympathetic Activation
A Phase 4 study testing melatonin in people with Healthy, run by University of Oklahoma at 1 site in United States.
Trial summary
the purpose of this experiment is to determine if acute melatonin supplementation alters central and peripheral cardiovascular responses to a cold pressor test at rest and during dynamic exercise. Read more about this study
- Who is it for?
- Ages 18 to 35 yearsHealthy volunteers can take part
- Conditions the study is for
- Healthy
- What is being tested?
- melatonin
- Could I receive a placebo?
- Yes, some participants may receive a placebo
- How many people
- 100 participants
- Where
- 1 siteUnited States
- Study dates
- 1 Jan 2023to Dec 2026
- Phase
- Phase 4
- 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 18 to 35 years
- All sexes
- Healthy volunteers accepted
- Adult
Who may be able to join
- Healthy men and women
- Women must be premenopausal with a regular menstrual cycle (26-30 days)
Who cannot join
- History of autonomic dysfunction
- Cardiovascular diseases
- Diabetes
- Tobacco/nicotine use
- Systolic Pressure >= 130 mmHg
- Diastolic Pressure >= 85 mmHg
Show all 11Show fewer
- Regular melatonin use >= 1 use/week
- Allergy to melatonin
- Cardiometabolic medication use (e.g. anti-hypertensives, insulin-sensitizing, statins)
- Sex hormone replacement medical use (e.g. testosterone, estrogen, progesterone)
- Pregnancy
Trial locations and contacts
1 site in 1 country.
United States1 site
Department of Health and Exercise Science
Norman, Oklahoma, 73019
About this study
the purpose of this experiment is to determine if acute melatonin supplementation alters central and peripheral cardiovascular responses to a cold pressor test at rest and during dynamic exercise.
Read the detailed description
After IRB approval, experiments will take place in the Human Circulation Research Laboratory in the Department of Health and Exercise on the University of Oklahoma Norman campus. All subjects will complete a total of 3 visits. The first is a screening visit to provide informed consent and to ensure the potential participant meets all inclusion criteria and no exclusion criteria. Once consented and enrolled, participants will be familiarized with experimental protocols. On separate days (visits 2 and 3), participants will complete placebo (PLA) and melatonin (MEL) in a randomly ordered, single-blind, counter-balanced design. PLA or MEL treatment will precede testing by 30min to maximize absorption into the circulation (Bartoli, 2013).
All experiments (PLA/MEL) will begin with the subject lying supine for 5 min of quiet rest where baseline measurements are taken, followed by activation of the lower body negative pressure (LBNP) device causing suction at -20 mmHg. Following LBNP participants will be given 10 minutes of rest to recover all variables to pre-LBNP values. After which participants will be given a hand grip dynamometer to complete 7 minutes of exercise at an intensity of 20% MVC at a 1s contraction to 2s relaxation cycle paced by a metronome. During the final 2 minutes of the 7 minutes of exercise the LBNP device will be activated again to -20mmHg such that the participant will be completing LBNP during rhythmic grip exercise. After the completion of exercise, the subject will remain supine for 10min. Then the a Total Labile Signal (TLS) procedure will be conducted. Where the experimental limb is occluded using a blood pressure cuff for 5min. The cuff is then rapidly deflated. The lowest oxyhemoglobin measured during the occlusion is recorded. After the TLS procedure, the subject will be de-instrumented and will leave the laboratory.
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
melatoninDietary supplement
A 5mg dose of melatonin spay will be delivered sublingually.
PlaceboOther
10 sprays of diluted mint extract. This mimics the sensation and taste of the melatonin spray
| Study group | Role | What they receive |
|---|---|---|
| Placebo | Placebo comparator | Placebo (PLA) is 10 sublingual sprays of a diluted (1 microliter/29ml filtered water) mint extract. Receives: Other: Placebo |
| Melatonin | Experimental | 5mg commercially available melatonin (MEL) spray will be given sublingually. Receives: Dietary Supplement: melatonin |
What is being measured
The primary outcome is the main question the study is designed to answer.
Muscle Tissue Oxygenation
Concentrations of Total, Oxy, and deoxyhemoglobin of Flexor Digitorum Profundus muscle of the forearm
Measured: 7 minutes of rest and 7 minutes of exercise
Mean Arterial Pressure
average pressure within the arteries
Measured: 7 minutes of rest and 7 minutes of exercise
Secondary outcomes (7)
Cerebral Oxygenation
Concentrations of Total, Oxy, and deoxyhemoglobin of the Prefrontal Cortex of the brain
Measured: 7 minutes of rest and 7 minutes of exercise
Heart Rate
number of heart beats per minute
Measured: 7 minutes of rest and 7 minutes of exercise
Respiratory Rate
number of breaths per minute
Measured: 7 minutes of rest and 7 minutes of exercise
Cardiac Output
volume of blood pumped by the heart per minute
Measured: 7 minutes of rest and 7 minutes of exercise
Stroke Volume
volume of blood pumped by the heart per heart beat
Measured: 7 minutes of rest and 7 minutes of exercise
Total peripheral resistance
amount of force affecting resistance to blood flow throughout the circulatory system
Measured: 7 minutes of rest and 7 minutes of exercise
Heart Rate Variability
measure of the variation in time between each heart beat
Measured: 7 minutes of rest and 7 minutes of exercise
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted5 Apr 2021
- Study start1 Jan 2023
- Primary completionNov 2026 (estimated)
- Study completionDec 2026 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for HealthyStudies of the same condition, open and under way.
- More trials run by University of OklahomaThe sponsor's other registered studies.
- 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 4
- Primary purpose
- Basic science
- Allocation
- Randomised
- Intervention model
- Crossover
- Model description
- This study is a single-blind crossover design.
- Masking
- Single blind
- Who is masked
- Participant
- Enrolment
- 100 participants (estimated)
Sponsor and investigators
- Lead sponsor
- University of Oklahoma
- Sponsor type
- University, hospital or other
- Responsible party
- Sponsor
- Investigators
- Jeremy M Kellawan, Principal investigator, University of Oklahoma
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT04831398
- Sponsor's protocol ID
- 13084
- Status last verified
- Apr 2026
- First submitted
- 1 Apr 2021
- Last updated
- 5 May 2026
- Results posted
- No
- Data monitoring committee
- Yes
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- No: The is no plan to share IPD
Study at a glance
From the registry record, last updated by the sponsor on 5 May 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- The Effects of Acute Melatonin Supplementation on Cardiovascular Responses to Sympathetic Activation
- ClinicalTrials.gov ID
- NCT04831398
- Acronym / sponsor ID
- 13084
- Conditions
- Healthy
- Phase
- Phase 4
- Study type
- Interventional
- Recruitment status
- Active, not recruiting
- Enrolment
- 100 participants (estimated)
- Lead sponsor
- University of OklahomaUniversity, hospital or other
- Study start
- 1 Jan 2023 (actual)
- Primary completion
- Nov 2026 (estimated)
- Study completion
- Dec 2026 (estimated)
- First posted
- 5 Apr 2021 (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 experiment is to determine if acute melatonin supplementation alters central and peripheral cardiovascular responses to a cold pressor test at rest and during dynamic exercise.
Detailed description
After IRB approval, experiments will take place in the Human Circulation Research Laboratory in the Department of Health and Exercise on the University of Oklahoma Norman campus. All subjects will complete a total of 3 visits. The first is a screening visit to provide informed consent and to ensure the potential participant meets all inclusion criteria and no exclusion criteria. Once consented and enrolled, participants will be familiarized with experimental protocols. On separate days (visits 2 and 3), participants will complete placebo (PLA) and melatonin (MEL) in a randomly ordered, single-blind, counter-balanced design. PLA or MEL treatment will precede testing by 30min to maximize absorption into the circulation (Bartoli, 2013).
All experiments (PLA/MEL) will begin with the subject lying supine for 5 min of quiet rest where baseline measurements are taken, followed by activation of the lower body negative pressure (LBNP) device causing suction at -20 mmHg. Following LBNP participants will be given 10 minutes of rest to recover all variables to pre-LBNP values. After which participants will be given a hand grip dynamometer to complete 7 minutes of exercise at an intensity of 20% MVC at a 1s contraction to 2s relaxation cycle paced by a metronome. During the final 2 minutes of the 7 minutes of exercise the LBNP device will be activated again to -20mmHg such that the participant will be completing LBNP during rhythmic grip exercise. After the completion of exercise, the subject will remain supine for 10min. Then the a Total Labile Signal (TLS) procedure will be conducted. Where the experimental limb is occluded using a blood pressure cuff for 5min. The cuff is then rapidly deflated. The lowest oxyhemoglobin measured during the occlusion is recorded. After the TLS procedure, the subject will be de-instrumented and will leave the laboratory.
Study design
- Primary purpose
- Basic science
- Allocation
- Randomised
- Intervention model
- Crossover
- Masking
- Single blind (participant)
- Number of arms
- 2
- Model description
- This study is a single-blind crossover design.
| Arm | Type | Receives |
|---|---|---|
| Placebo | Placebo comparator | Other: PlaceboPlacebo (PLA) is 10 sublingual sprays of a diluted (1 microliter/29ml filtered water) mint extract. |
| Melatonin | Experimental | Dietary Supplement: melatonin5mg commercially available melatonin (MEL) spray will be given sublingually. |
Who may qualify
- Ages
- 18 to 35 years
- Sex
- All
- Healthy volunteers
- Accepted
- Age groups
- Adult
Key inclusion criteria (2 listed)
- Healthy men and women
- Women must be premenopausal with a regular menstrual cycle (26-30 days)
Key exclusion criteria (11 listed)
- History of autonomic dysfunction
- Cardiovascular diseases
- Diabetes
- Tobacco/nicotine use
- Systolic Pressure >= 130 mmHg
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 |
|---|---|---|
| melatoninA 5mg dose of melatonin spay will be delivered sublingually. | Dietary supplement | Melatonin |
| Placebo10 sprays of diluted mint extract. This mimics the sensation and taste of the melatonin spray | Other | Placebo |
Primary outcome
Muscle Tissue Oxygenation
Time frame: 7 minutes of rest and 7 minutes of exercise
Concentrations of Total, Oxy, and deoxyhemoglobin of Flexor Digitorum Profundus muscle of the forearm
Mean Arterial Pressure
Time frame: 7 minutes of rest and 7 minutes of exercise
average pressure within the arteries
7 secondary outcomes
Cerebral Oxygenation
Time frame: 7 minutes of rest and 7 minutes of exercise
Heart Rate
Time frame: 7 minutes of rest and 7 minutes of exercise
Respiratory Rate
Time frame: 7 minutes of rest and 7 minutes of exercise
Cardiac Output
Time frame: 7 minutes of rest and 7 minutes of exercise
Stroke Volume
Time frame: 7 minutes of rest and 7 minutes of exercise
Total peripheral resistance
Time frame: 7 minutes of rest and 7 minutes of exercise
Heart Rate Variability
Time frame: 7 minutes of rest and 7 minutes of exercise
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 5 May 2026.
- Individual participant dataSharing planned: No. The is no plan to share IPD
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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.
Jeremy M Kellawan principal investigator
University of Oklahoma
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A Phase 4 study testing melatonin in people with Healthy, run by University of Oklahoma 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 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 5 May 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. Some participants in this study may receive a placebo. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
What does this phase mean?
Phase 4 studies take place after a treatment is approved, to learn more about its long-term benefits and risks in everyday use.
Not every study follows the same path, and some studies (observational studies, device studies) have no phase.
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?
Muscle Tissue Oxygenation (time frame: 7 minutes of rest and 7 minutes of exercise). The study lists 2 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 5 May 2026.