Health Adult SubjectsNCT07344636
Effects of NR Supplementation on Metabolic Flexibility in Zone 2 Training
A study testing Nicotinamide Riboside (NR) in people with Health Adult Subjects, run by ZHANG Jiaqi at 1 site in China.
Trial summary
Zone 2 training, a low-intensity endurance exercise performed at approximately 66-80% of VO₂max or near the first ventilatory threshold, has gained popularity for improving aerobic capacity, fat metabolism, and mitochondrial efficiency. Read more about this study
- Who is it for?
- Ages 18 to 80 yearsHealthy volunteers can take part
- Conditions the study is for
- Health Adult Subjects
- What is being tested?
- Nicotinamide Riboside (NR)
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 16 participants
- Where
- 1 siteChina
- Study dates
- 6 Jan 2026to 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 18 to 80 years
- All sexes
- Healthy volunteers accepted
- Adult, Older adult
Who may be able to join
- Over 18 years old
- BMI <30 kg/m2
Who cannot join
- Present of health conditions that contraindicate participation in exercise training, such as a history of cardiovascular disease, cancer, or musculoskeletal disorders
- Currently taking vitamin B supplements and/or NAD precursors
- Taking medication that may affect the test results
Trial locations and contacts
1 site in 1 country. Contact the study team or a site near you to ask about taking part.
China1 site, 1 recruiting
- Recruiting
G02, Kwok Sports Building, The Chinese University of Hong Kong
Hong Kong, Please Select, 999077
Jiaqi ZHANG, 852 95596303, z.jiaqi@link.cuhk.edu.hk
About this study
Official title: Temporal and Dose-response Effects of Nicotinamide Riboside Supplementation on Metabolic Flexibility During Zone 2 Training in Adults: a Double-blinded, Randomized, Controlled, Crossover Trial
Zone 2 training, a low-intensity endurance exercise performed at approximately 66-80% of VO₂max or near the first ventilatory threshold, has gained popularity for improving aerobic capacity, fat metabolism, and mitochondrial efficiency. It preserves glycogen stores and delays fatigue, making it an essential training method for both athletes and recreational exercisers. Nicotinamide adenine dinucleotide (NAD) is a vital metabolite that regulates cellular energy metabolism and redox homeostasis. It participates in oxidative reactions within the tricarboxylic acid cycle and electron transport chain, sustaining ATP synthesis and mitochondrial efficiency. Exercise influences multiple pathways of NAD metabolism, altering the NAD⁺/NADH ratio and thereby affecting energy production and fatigue resistance. Studies have shown that both aerobic exercise and NAD precursor supplementation (e.g., nicotinamide riboside [NR]) can elevate body NAD levels and enhance mitochondrial function, though findings remain inconsistent due to variations in dosage and participants' characteristics. This study aims to investigate how acute NR supplementation interacts with Zone 2 cycling training in adults. Specifically, it examines the temporal and dose-dependent effects of NR supplementation on metabolic flexibility and exercise performance. The results may clarify the potential synergistic benefits of combining NAD supplementation with low-intensity endurance training to improve aerobic adaptability.
- Conditions
- Health Adult Subjects
- Being tested
- Nicotinamide Riboside (NR)
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Nicotinamide Riboside (NR)Dietary supplement
600 mg NR
Nicotinamide Riboside (NR)Dietary supplement
300 mg NR
| Study group | Role | What they receive |
|---|---|---|
| 600 mg | Experimental | Not described Receives: Dietary Supplement: Nicotinamide Riboside (NR) |
| 300 mg | Experimental | Not described Receives: Dietary Supplement: Nicotinamide Riboside (NR) |
| 0 mg | No intervention | Not described |
What is being measured
The primary outcome is the main question the study is designed to answer.
Substrate utilization (CHO and fat oxidation rate)
Measured: From enrollment to the end of treatment at 4 weeks
Secondary outcomes (9)
Oxygen consumption
Measured: From enrollment to the end of treatment at 4 weeks
Heart rate
Measured: From enrollment to the end of treatment at 4 weeks
Blood glucose concentration
Measured: From enrollment to the end of treatment at 4 weeks
Blood lactate concentration
Measured: From enrollment to the end of treatment at 4 weeks
Peak power output
Measured: From enrollment to the end of treatment at 4 weeks
Mean power output
Measured: From enrollment to the end of treatment at 4 weeks
Rating of perceived exertion
Measured: From enrollment to the end of treatment at 4 weeks
Muscle pain scale
Muscle pain scale is a 5-point likert scale ranging from "1- Not at all" to "5- Extreme", with higher value indicating muscle pain.
Measured: From enrollment to the end of treatment at 4 weeks
Muscle fatigue scale
Muscle fatigue scale is a 5-point likert scale ranging from "1- Not at all" to "5- Extreme", with higher value indicating muscle fatigue.
Measured: From enrollment to the end of treatment at 4 weeks
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted15 Jan 2026
- Study start6 Jan 2026
- Primary completionJul 2027 (estimated)
- Study completionJul 2027 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Health Adult SubjectsStudies 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
- Other
- Allocation
- Randomised
- Intervention model
- Crossover
- Masking
- Double blind
- Who is masked
- Participant, Outcomes assessor
- Enrolment
- 16 participants (estimated)
Sponsor and investigators
- Lead sponsor
- ZHANG Jiaqi
- Sponsor type
- University, hospital or other
- Responsible party
- Sponsor-investigator, ZHANG Jiaqi, Chinese University of Hong Kong
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07344636
- Sponsor's protocol ID
- SBRE-25-0349
- Status last verified
- Mar 2026
- First submitted
- 5 Jan 2026
- Last updated
- 18 Mar 2026
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- Undecided
Study at a glance
From the registry record, last updated by the sponsor on 18 Mar 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Temporal and Dose-response Effects of Nicotinamide Riboside Supplementation on Metabolic Flexibility During Zone 2 Training in Adults: a Double-blinded, Randomized, Controlled, Crossover Trial
- ClinicalTrials.gov ID
- NCT07344636
- Acronym / sponsor ID
- SBRE-25-0349
- Conditions
- Health Adult Subjects
- Study type
- Interventional
- Recruitment status
- Recruiting
- Enrolment
- 16 participants (estimated)
- Lead sponsor
- ZHANG JiaqiUniversity, hospital or other
- Study start
- 6 Jan 2026 (actual)
- Primary completion
- Jul 2027 (estimated)
- Study completion
- Jul 2027 (estimated)
- First posted
- 15 Jan 2026 (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.
Zone 2 training, a low-intensity endurance exercise performed at approximately 66-80% of VO₂max or near the first ventilatory threshold, has gained popularity for improving aerobic capacity, fat metabolism, and mitochondrial efficiency. It preserves glycogen stores and delays fatigue, making it an essential training method for both athletes and recreational exercisers. Nicotinamide adenine dinucleotide (NAD) is a vital metabolite that regulates cellular energy metabolism and redox homeostasis. It participates in oxidative reactions within the tricarboxylic acid cycle and electron transport chain, sustaining ATP synthesis and mitochondrial efficiency. Exercise influences multiple pathways of NAD metabolism, altering the NAD⁺/NADH ratio and thereby affecting energy production and fatigue resistance. Studies have shown that both aerobic exercise and NAD precursor supplementation (e.g., nicotinamide riboside [NR]) can elevate body NAD levels and enhance mitochondrial function, though findings remain inconsistent due to variations in dosage and participants' characteristics. This study aims to investigate how acute NR supplementation interacts with Zone 2 cycling training in adults. Specifically, it examines the temporal and dose-dependent effects of NR supplementation on metabolic flexibility and exercise performance. The results may clarify the potential synergistic benefits of combining NAD supplementation with low-intensity endurance training to improve aerobic adaptability.
Study design
- Primary purpose
- Other
- Allocation
- Randomised
- Intervention model
- Crossover
- Masking
- Double blind (participant, outcomes assessor)
- Number of arms
- 3
| Arm | Type | Receives |
|---|---|---|
| 600 mg | Experimental | Dietary Supplement: Nicotinamide Riboside (NR) |
| 300 mg | Experimental | Dietary Supplement: Nicotinamide Riboside (NR) |
| 0 mg | No intervention | – |
Who may qualify
- Ages
- 18 to 80 years
- Sex
- All
- Healthy volunteers
- Accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (2 listed)
- Over 18 years old
- BMI <30 kg/m2
Key exclusion criteria (3 listed)
- Present of health conditions that contraindicate participation in exercise training, such as a history of cardiovascular disease, cancer, or musculoskeletal disorders
- Currently taking vitamin B supplements and/or NAD precursors
- Taking medication that may affect the test results
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 |
|---|---|---|
| Nicotinamide Riboside (NR)600 mg NR | Dietary supplement | 600 mg |
| Nicotinamide Riboside (NR)300 mg NR | Dietary supplement | 300 mg |
Primary outcome
Substrate utilization (CHO and fat oxidation rate)
Time frame: From enrollment to the end of treatment at 4 weeks
9 secondary outcomes
Oxygen consumption
Time frame: From enrollment to the end of treatment at 4 weeks
Heart rate
Time frame: From enrollment to the end of treatment at 4 weeks
Blood glucose concentration
Time frame: From enrollment to the end of treatment at 4 weeks
Blood lactate concentration
Time frame: From enrollment to the end of treatment at 4 weeks
Peak power output
Time frame: From enrollment to the end of treatment at 4 weeks
Mean power output
Time frame: From enrollment to the end of treatment at 4 weeks
Rating of perceived exertion
Time frame: From enrollment to the end of treatment at 4 weeks
Muscle pain scale
Time frame: From enrollment to the end of treatment at 4 weeks
Muscle fatigue scale
Time frame: From enrollment to the end of treatment at 4 weeks
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 18 Mar 2026.
- Individual participant dataSharing planned: Undecided
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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.
G02, Kwok Sports Building, The Chinese University of Hong Kong
Hong Kong, China
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing Nicotinamide Riboside (NR) in people with Health Adult Subjects, run by ZHANG Jiaqi at 1 site in China.
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 3 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 18 Mar 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 China. 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?
Each site lists its own contact: choose the nearest one under Trial locations. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Substrate utilization (CHO and fat oxidation rate) (time frame: From enrollment to the end of treatment at 4 weeks). 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 18 Mar 2026.