Recovery MethodsNCT07492446
Effects of Carnitine Supplementation on Exercise-Induced Muscle Damage: A Randomized Controlled Trial
A study testing L-Carnitine in people with Recovery Methods and Exercise and Recovery, run by Istanbul Sabahattin Zaim University at 1 site in Turkey (Türkiye).
Trial summary
This clinical study aims to investigate the effects of L-carnitine supplementation on recovery following high-intensity interval exercise in young athletes. L-carnitine plays an important role in energy metabolism by facilitating the transport of long-chain fatty acids into the mitochondria for oxidation. Read more about this study
- Who is it for?
- Ages 18 to 25 years, men onlyHealthy volunteers can take part
- Conditions the study is for
- Recovery Methods, Exercise and Recovery, Exercise Fatigue
- What is being tested?
- L-Carnitine
- Type of treatment
- Pill or oral medicine
- Could I receive a placebo?
- Yes, some participants may receive a placebo
- How many people
- 30 participants
- Where
- 1 siteTurkey (Türkiye)
- Study dates
- 9 May 2025to 5 Jun 2025
- Phase
- Interventional
- Are there results?
- None posted in the registry
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 25 years
- Men only
- Healthy volunteers accepted
- Adult
Who may be able to join
- Male athletes aged 18-25 years
- Regularly participating in organized sports training for at least 3 days per week
- Healthy individuals with no diagnosed cardiovascular, metabolic, or musculoskeletal disorders
- Willingness to comply with the supplementation protocol for 21 days
- Agreement to refrain from consuming foods rich in carnitine (e.g., meat and dairy products) during the supplementation period
- Agreement to avoid unfamiliar or strenuous exercise, particularly resistance exercise involving eccentric contractions, for one week prior to the experimental protocol
- Provision of written informed consent to participate in the study
Who cannot join
- Use of dietary supplements (including L-carnitine) within the last 3 weeks
- Presence of musculoskeletal injury or chronic disease that may affect exercise performance
- Use of medications that may influence muscle metabolism or recovery
- Known allergy or intolerance to the supplement components
- Failure to comply with the dietary or supplementation protocol
- Participation in another clinical or exercise intervention study during the study period
- Any condition deemed unsuitable for participation by the research team
Trial locations and contacts
1 site in 1 country.
Turkey (Türkiye)1 site
Istanbul Sabahattin Zaim University, Faculty of Sports Sciences
Istanbul, Küçükçekmece, 34303
About this study
Official title: INVESTIGATION OF THE EFFECT OF L-CARNITINE SUPPLEMENTS IN ATHLETES ON MUSCLE DAMAGE AND DELAYED ONSET MUSCLE PAIN (DOMS) AFTER HIGH INTENSITY INTERVAL TRAINING
This clinical study aims to investigate the effects of L-carnitine supplementation on recovery following high-intensity interval exercise in young athletes. L-carnitine plays an important role in energy metabolism by facilitating the transport of long-chain fatty acids into the mitochondria for oxidation. It has been suggested that L-carnitine supplementation may contribute to improved exercise performance and recovery by reducing metabolic stress and muscle damage associated with high-intensity exercise.
The primary objective of this study is to determine whether L-carnitine supplementation can attenuate exercise-induced muscle damage and delayed onset muscle soreness (DOMS) following high-intensity exercise. In addition, the study aims to evaluate the potential effects of L-carnitine on peak blood lactate concentration, as well as performance-related parameters including maximal power output, relative maximal power output, mean power output, and relative mean power output during high-intensity exercise.
Read more
To address these objectives, participants will be randomly assigned to receive either L-carnitine supplementation or a placebo for a period of 21 days. The placebo will consist of an inert substance designed to resemble the supplement but without any active ingredient. The effects of supplementation on performance and recovery outcomes will be evaluated following a standardized high-intensity exercise protocol.
Participants will be instructed to take the assigned supplement daily throughout the supplementation period. Communication and compliance monitoring will be conducted through a WhatsApp group established by the research team, which will be used to provide reminders and ensure adherence to the study protocol.
To minimize potential confounding factors related to pre-existing muscle damage, participants will be instructed to avoid unfamiliar or strenuous physical activity, particularly resistance exercises involving eccentric contractions, for one week prior to the experimental protocol. Additionally, during the supplementation period, participants will be asked to refrain from consuming foods rich in carnitine, such as meat and dairy products, in order to control dietary carnitine intake.
The findings of this study are expected to provide further insight into the potential role of L-carnitine supplementation in enhancing exercise performance and promoting recovery following high-intensity exercise in young athletes.
- Conditions
- Recovery Methods, Exercise and Recovery, Exercise Fatigue, Carnitine Ingestion, Exercise Ergogenics
- Being tested
- L-Carnitine, Placebo
- Keywords
- L-Carnitine Supplementation, High-Intensity Interval Exercise, Exercise-Induced Muscle Damage, Delayed Onset Muscle Soreness (DOMS), Exercise Recovery
- Medical subject headings
- Motor Activity
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
L-CarnitineDietary supplement
Also called Participants will consume 3 g/day of L-carnitine for 21 days.
Although the optimal dose and method of L-Carnitine use are not clearly defined in the literature, it has been reported that daily doses of 2-4 g are relatively ineffective in raising plasma levels unless used due to bioavailability. On the other hand, it has been suggested that the absolute bioavailability of oral doses greater than 1 g is less than 20% due to low gastrointestinal membrane permeability and limited capacity of intestinal transporters. However, pharmacokinetic data support the administration of L-Carnitine in several doses per day. Therefore, while the literature shows varying doses ranging from 1-4 g/day, generally in single daily doses, in this study, L-Carnitine participants will be given 3 g (3 g/d) of L-Carnitine daily for 3 weeks, at 1 g (1 g/8h) every 8 hours.
PlaceboOther
Also called Placebo participants will be given 3g/d of L-carnitine-like powdered sugar for 21 days.
In this study, placebo group participants will be given 3 grams (3g/d) of powdered sugar daily (1g/8h) at 8-hour intervals for 3 weeks, which resembles L-Carnitine supplements in shape and color.
| Study group | Role | What they receive |
|---|---|---|
| L-Carnitine Supplementation Group | Experimental | Participants in this group will receive L-carnitine supplementation for 21 days prior to completing a standardized high-intensity interval exercise protocol. The effects of supplementation on exercise-induced muscle damage, recovery, blood lactate levels, and anaerobic performance will be evaluated. Receives: Dietary Supplement: L-Carnitine |
| Placebo Group | Placebo comparator | Participants in this group will receive a placebo supplement identical in appearance to the L-carnitine supplement for 21 days prior to the high-intensity interval exercise protocol. Receives: Other: Placebo |
What is being measured
The primary outcome is the main question the study is designed to answer.
Exercise-Induced Muscle Damage (Creatine Kinase and LDH)
Exercise-induced muscle damage will be assessed using blood biomarkers, including creatine kinase (CK) and lactate dehydrogenase (LDH) concentrations measured after the high-intensity interval exercise protocol.
Measured: Immediately before starting a 21-day L-Carnitine supplement, Immediately after 21 days of L-Carnitine supplementation and 2 hours, 24 hours, 48 hours, and 72 hours after the exercise protocol.
Secondary outcomes (6)
Delayed Onset Muscle Soreness (DOMS)
Perceived muscle soreness will be evaluated using a visual analog scale (VAS) to assess delayed onset muscle soreness following the high-intensity exercise protocol.
Measured: Immediately after exercise and 2 hours, 24 hours, 48 hours, and 72 hours post-exercise
Peak Blood Lactate Concentration
Peak blood lactate concentration will be measured to evaluate the metabolic response to the high-intensity exercise protocol.
Measured: Immediately before the exercise test, and at 1, 3, 5, 7, 9, and 11 minutes after the exercise test ends.
Maximal Power Output
Maximal power output during the high-intensity exercise protocol will be recorded to evaluate anaerobic performance.
Measured: The 4*30 second exercise protocol: immediately after the first 30 seconds, immediately after the second 30 seconds, immediately after the third 30 seconds, immediately after the fourth 30 seconds.
Relative Maximal Power Output
Relative maximal power output (power normalized to body mass) will be assessed to evaluate anaerobic performance.
Measured: The 4*30 second exercise protocol: immediately after the first 30 seconds, immediately after the second 30 seconds, immediately after the third 30 seconds, immediately after the fourth 30 seconds.
Mean Power Output
Mean power output during the exercise protocol will be recorded as an indicator of anaerobic performance.
Measured: The 4*30 second exercise protocol: immediately after the first 30 seconds, immediately after the second 30 seconds, immediately after the third 30 seconds, immediately after the fourth 30 seconds.
Relative Mean Power Output
Relative mean power output normalized to body mass will be calculated to evaluate anaerobic performance.
Measured: The 4*30 second exercise protocol: immediately after the first 30 seconds, immediately after the second 30 seconds, immediately after the third 30 seconds, immediately after the fourth 30 seconds.
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted25 Mar 2026
- Study start9 May 2025
- Primary completion15 May 2025
- Study completion5 Jun 2025
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Recovery MethodsStudies 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
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Double blind
- Who is masked
- Participant, Investigator
- Enrolment
- 30 participants (actual)
Sponsor and investigators
- Lead sponsor
- Istanbul Sabahattin Zaim University
- Sponsor type
- University, hospital or other
- Collaborators
- T.C. Dumlupınar Üniversitesi
- Responsible party
- Principal investigator, Muhammet Yilmaz, Istanbul Sabahattin Zaim University
- Investigators
- Halit HARMANCI, Professor Doctor, Study director, Republic of Turkey KUtahya Dumlupınar University
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07492446
- Sponsor's protocol ID
- E-95961207-604.01.01-2245
- Other IDs
- Kutahya Dumlupınar University
- Status last verified
- Mar 2026
- First submitted
- 13 Mar 2026
- Last updated
- 25 Mar 2026
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- No: Data privacy, Ethics committee restrictions, Risk of misinterpretation of data
Study at a glance
From the registry record, last updated by the sponsor on 25 Mar 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- INVESTIGATION OF THE EFFECT OF L-CARNITINE SUPPLEMENTS IN ATHLETES ON MUSCLE DAMAGE AND DELAYED ONSET MUSCLE PAIN (DOMS) AFTER HIGH INTENSITY INTERVAL TRAINING
- ClinicalTrials.gov ID
- NCT07492446
- Acronym / sponsor ID
- E-95961207-604.01.01-2245
- Conditions
- Recovery Methods, Exercise and Recovery, Exercise Fatigue, Carnitine Ingestion, Exercise Ergogenics
- Keywords
- L-Carnitine Supplementation, High-Intensity Interval Exercise, Exercise-Induced Muscle Damage, Delayed Onset Muscle Soreness (DOMS), Exercise Recovery
- Study type
- Interventional
- Recruitment status
- Completed
- Enrolment
- 30 participants (actual)
- Lead sponsor
- Istanbul Sabahattin Zaim UniversityUniversity, hospital or other
- Collaborators
- T.C. Dumlupınar Üniversitesi
- Study start
- 9 May 2025 (actual)
- Primary completion
- 15 May 2025 (actual)
- Study completion
- 5 Jun 2025 (actual)
- First posted
- 25 Mar 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.
This clinical study aims to investigate the effects of L-carnitine supplementation on recovery following high-intensity interval exercise in young athletes. L-carnitine plays an important role in energy metabolism by facilitating the transport of long-chain fatty acids into the mitochondria for oxidation. It has been suggested that L-carnitine supplementation may contribute to improved exercise performance and recovery by reducing metabolic stress and muscle damage associated with high-intensity exercise.
The primary objective of this study is to determine whether L-carnitine supplementation can attenuate exercise-induced muscle damage and delayed onset muscle soreness (DOMS) following high-intensity exercise. In addition, the study aims to evaluate the potential effects of L-carnitine on peak blood lactate concentration, as well as performance-related parameters including maximal power output, relative maximal power output, mean power output, and relative mean power output during high-intensity exercise.
To address these objectives, participants will be randomly assigned to receive either L-carnitine supplementation or a placebo for a period of 21 days. The placebo will consist of an inert substance designed to resemble the supplement but without any active ingredient. The effects of supplementation on performance and recovery outcomes will be evaluated following a standardized high-intensity exercise protocol.
Participants will be instructed to take the assigned supplement daily throughout the supplementation period. Communication and compliance monitoring will be conducted through a WhatsApp group established by the research team, which will be used to provide reminders and ensure adherence to the study protocol.
To minimize potential confounding factors related to pre-existing muscle damage, participants will be instructed to avoid unfamiliar or strenuous physical activity, particularly resistance exercises involving eccentric contractions, for one week prior to the experimental protocol. Additionally, during the supplementation period, participants will be asked to refrain from consuming foods rich in carnitine, such as meat and dairy products, in order to control dietary carnitine intake.
The findings of this study are expected to provide further insight into the potential role of L-carnitine supplementation in enhancing exercise performance and promoting recovery following high-intensity exercise in young athletes.
Study design
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Double blind (participant, investigator)
- Number of arms
- 2
| Arm | Type | Receives |
|---|---|---|
| L-Carnitine Supplementation Group | Experimental | Dietary Supplement: L-CarnitineParticipants in this group will receive L-carnitine supplementation for 21 days prior to completing a standardized high-intensity interval exercise protocol. The effects of supplementation on exercise-induced muscle damage, recovery, blood lactate levels, and anaerobic performance will be evaluated. |
| Placebo Group | Placebo comparator | Other: PlaceboParticipants in this group will receive a placebo supplement identical in appearance to the L-carnitine supplement for 21 days prior to the high-intensity interval exercise protocol. |
Who may qualify
- Ages
- 18 to 25 years
- Sex
- Male only
- Healthy volunteers
- Accepted
- Age groups
- Adult
Key inclusion criteria (7 listed)
- Male athletes aged 18-25 years
- Regularly participating in organized sports training for at least 3 days per week
- Healthy individuals with no diagnosed cardiovascular, metabolic, or musculoskeletal disorders
- Willingness to comply with the supplementation protocol for 21 days
- Agreement to refrain from consuming foods rich in carnitine (e.g., meat and dairy products) during the supplementation period
Key exclusion criteria (7 listed)
- Use of dietary supplements (including L-carnitine) within the last 3 weeks
- Presence of musculoskeletal injury or chronic disease that may affect exercise performance
- Use of medications that may influence muscle metabolism or recovery
- Known allergy or intolerance to the supplement components
- Failure to comply with the dietary or supplementation protocol
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 |
|---|---|---|
| L-CarnitineAlso: Participants will consume 3 g/day of L-carnitine for 21 days.Although the optimal dose and method of L-Carnitine use are not clearly defined in the literature, it has been reported that daily doses of 2-4 g are relatively ineffective in raising plasma levels unless used due to bioavailability. On the other hand, it has been suggested that the absolute bioavailability of oral doses greater than 1 g is less than 20% due to low gastrointestinal membrane permeability and limited capacity of intestinal transporters. However, pharmacokinetic data support the administration of L-Carnitine in several doses per day. Therefore, while the literature shows varying doses ranging from 1-4 g/day, generally in single daily doses, in this study, L-Carnitine participants will be given 3 g (3 g/d) of L-Carnitine daily for 3 weeks, at 1 g (1 g/8h) every 8 hours. | Dietary supplement | L-Carnitine Supplementation Group |
| PlaceboAlso: Placebo participants will be given 3g/d of L-carnitine-like powdered sugar for 21 days.In this study, placebo group participants will be given 3 grams (3g/d) of powdered sugar daily (1g/8h) at 8-hour intervals for 3 weeks, which resembles L-Carnitine supplements in shape and color. | Other | Placebo Group |
Primary outcome
Exercise-Induced Muscle Damage (Creatine Kinase and LDH)
Time frame: Immediately before starting a 21-day L-Carnitine supplement, Immediately after 21 days of L-Carnitine supplementation and 2 hours, 24 hours, 48 hours, and 72 hours after the exercise protocol.
Exercise-induced muscle damage will be assessed using blood biomarkers, including creatine kinase (CK) and lactate dehydrogenase (LDH) concentrations measured after the high-intensity interval exercise protocol.
6 secondary outcomes
Delayed Onset Muscle Soreness (DOMS)
Time frame: Immediately after exercise and 2 hours, 24 hours, 48 hours, and 72 hours post-exercise
Peak Blood Lactate Concentration
Time frame: Immediately before the exercise test, and at 1, 3, 5, 7, 9, and 11 minutes after the exercise test ends.
Maximal Power Output
Time frame: The 4*30 second exercise protocol: immediately after the first 30 seconds, immediately after the second 30 seconds, immediately after the third 30 seconds, immediately after the fourth 30 seconds.
Relative Maximal Power Output
Time frame: The 4*30 second exercise protocol: immediately after the first 30 seconds, immediately after the second 30 seconds, immediately after the third 30 seconds, immediately after the fourth 30 seconds.
Mean Power Output
Time frame: The 4*30 second exercise protocol: immediately after the first 30 seconds, immediately after the second 30 seconds, immediately after the third 30 seconds, immediately after the fourth 30 seconds.
Relative Mean Power Output
Time frame: The 4*30 second exercise protocol: immediately after the first 30 seconds, immediately after the second 30 seconds, immediately after the third 30 seconds, immediately after the fourth 30 seconds.
Results and safety
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 25 Mar 2026.
- Individual participant dataSharing planned: No. Data privacy, Ethics committee restrictions, Risk of misinterpretation of data
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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.
Halit HARMANCI, Professor Doctor study director
Republic of Turkey KUtahya Dumlupınar University
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing L-Carnitine in people with Recovery Methods and Exercise and Recovery, run by Istanbul Sabahattin Zaim University at 1 site in Turkey (Türkiye).
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 7 inclusion and 7 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: finished, as of the sponsor's last update on 25 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 Turkey (Türkiye). 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.
Are results available for this study?
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
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?
Exercise-Induced Muscle Damage (Creatine Kinase and LDH) (time frame: Immediately before starting a 21-day L-Carnitine supplement, Immediately after 21 days of L-Carnitine supplementation and 2 hours, 24 hours, 48 hours, and 72 hours after the exercise protocol.). 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 25 Mar 2026.