Focus on Omega 3 Index on RecoveryIMPROVE-8NCT07439601
Long-Term Omega-3 and Omega-3 Index >8%: Effects on Physiological Recovery
A study testing Oil Supplementation in people with Focus on Omega 3 Index on Recovery, run by St. Mary's University, Twickenham.
Trial summary
The Omega-3 Index measures how much of the Omega-3 fats EPA and DHA are built into red blood cell membranes. These fats are essential for health, but the body cannot make enough of them, so they must come from foods like oily fish or from supplements. Read more about this study
- Who is it for?
- Ages 18 to 50 yearsHealthy volunteers can take part
- Conditions the study is for
- Focus on Omega 3 Index on Recovery
- What is being tested?
- Oil Supplementation
- Type of treatment
- Pill or oral medicine
- Could I receive a placebo?
- Yes, some participants may receive a placebo
- How many people
- 46 participants
- Where
- No sites listed yet
- Study dates
- 28 Feb 2026to 30 Dec 2028
- 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 50 years
- All sexes
- Healthy volunteers accepted
- Adult
Who may be able to join
- An Omega-3 index of ≤ 6%
- Age 18-50 years
- Sub-elite to elite athletes from local sports teams (e.g. cycling, triathlon)
- Male and female
Who cannot join
- inflammatory diseases, injuries that prevent them exercising.
Trial locations and contacts
No sites are listed yet. Contact the study team or a site near you to ask about taking part.
About this study
Official title: The Impact of Long-term Omega-3 Supplementation and an Omega-3 Index Above 8% on Physiological Recovery Following Exercise-Induced Muscle Damage
The Omega-3 Index measures how much of the Omega-3 fats EPA and DHA are built into red blood cell membranes. These fats are essential for health, but the body cannot make enough of them, so they must come from foods like oily fish or from supplements. The Index reflects long-term Omega-3 intake and is considered optimal at 8% or higher. Levels below this range have been linked with poorer cardiovascular health (Harris \& Von Schacky, 2004).
. For athletes, Omega-3 research suggests they can help reduce inflammation, ease muscle soreness, and support immune function. Despite this, many elite athletes appear to have Omega-3 Index values around 4-5%, well below the recommended level of 8%.
Therefore, the aim of this study is to investigate whether increasing the Omega-3 index has any recovery benefits post a bout of downhill running in athletes. Downhill running is commonly used as way to cause exercise-induced muscle damage and study recovery. The Omega-3 index will be increased with a daily fish oil supplement.
Read the detailed description
The proposed research will follow quantitative methods using a randomized independent-groups design. Participants will be allocated to one of two conditions: a placebo group or a fish oil supplementation group. All testing will take place in the St. Mary's University Performance Labs.
Screening and Eligibility
At the initial visit, participants will provide informed consent and complete a PAR-Q form. Eligibility screening will include confirmation that participants have an Omega-3 index ≤ 5%, assessed via a dried blood spot sample obtained from a capillary finger-prick. Samples are processed by OmegaQuant at their lab in Stirling, and results are typically returned within one week.
Participants will also be excluded if they are currently consuming ≥1 g/day of fish-oil supplements.
Randomisation and Blinding
Eligible participants will be randomly assigned to one of the two experimental groups using a random number generator (https://www.random.org). The study will follow a double-blind design: participants will not know which supplement they receive, and the primary investigators involved in data collection will also remain blinded. Supplement distribution and any dose adjustments will be conducted by a separate member of the research team who is unblinded and not involved in testing of participants or data analysis.
Screening Tests/familiarisation
Once Omega-3 index results are available, eligible participants will return to the lab for physiological screening/familiarisation of the test battery and to receive their supplements. Screening/familiarisation procedures include:
- An incremental treadmill ramp test, starting at 8 km·h-¹ and increasing by 1 km·h-¹ every 3 minutes until volitional exhaustion. During the test the below measures will be taken:
- Capillary blood lactate sampling (finger or earlobe) every 3 minutes.
- Continuous breath-by-breath respiratory analysis using the Vyntus online gas analyser.
- Heart rate monitoring (Polar H10) and Rate of Perceived Exertion (RPE; Borg scale).
The screening session also introduces participants to the test battery illustrated in Figure 3.
Supplementation Phase (Part A)
Participants will be asked to refrain from:
- Alcohol for 48 hours before each testing session.
- Caffeine for 12 hours before each testing session.
Participants will consume their assigned supplements daily for four months. Investigators will contact participants approximately every four weeks to assess adherence and to distribute additional supplement supplies.
At two months, a repeat dried blood spot sample will assess whether Omega-3 levels in the fish-oil group are increasing as expected. If required, supplementation will be adjusted using the OmegaQuant calculator (https://omegaquant.com/omega-3-index-calculator/). Adjustments will typically involve changes of approximately 0.5 g/day (EPA + DHA).
To maintain double-blinding, placebo dosages will also be altered by ±0.5 g/day, ensuring both investigator and participant remain unaware of group allocation.
After four months, participants will provide another dried blood sample. The aim is for the fish-oil group to reach an Omega-3 index ≥ 8%. Participants who do not meet their target will continue supplementation for an additional 2-4 weeks, followed by another blood test, until the required level is achieved. A cut-off point 6 additional weeks will be incorporated.
Completion of this phase constitutes Part A: the supplementation phase. Exercise-Induced Muscle Damage Trial (Part B) Approximately one week before Part B, participants will return to the lab to complete a second treadmill ramp test to determine the appropriate speed for the downhill running protocol.
Participants will then attend the laboratory on four consecutive days to complete pre- and post-exercise assessments associated with the exercise-induced muscle damage protocol.
The proposed study requires participants to take fish oil supplementation in order to increase their Omega-3 index and investigate whether this produces performance or recovery benefits, beyond the well-established long-term health effects associated with approximately 3 g/day of EPA + DHA. Fish oil supplementation is widely used in both clinical and general health contexts and is considered safe at doses of up to 5 g/day, as recognised by the European Food Safety Authority.
Participants will be recruited to complete the supplementation phase and take part in an exercise-induced muscle damage (EIMD) protocol. They will be randomly allocated to one of the two study groups (fish oil or placebo).
Fish oil supplementation will be provided by OmegaQuant (https://parasolnutrition.com/product/omega-3-fish-oil/) , this supplement is commercially available
Test battery:
- Venous Blood Samples Venous blood samples will be collected to assess resting concentrations of inflammatory and muscle-damage biomarkers, including Interleukin-6 (IL-6), Interleukin-10 (IL-10), Tumor Necrosis Factor-α (TNF-α), myoglobin, lactate dehydrogenase (LDH), and creatine kinase (CK). Samples will be obtained by qualified phlebotomists at St Mary's University (Toby Helder, Prof. Charles Pedlar, and Dr Jessica Hill). All venous samples will be stored at -80°C and later analysed using enzyme-linked immunosorbent assays (ELISAs). Venous sampling will occur at all required testing timepoints.
- FORD/FORT Capillary Blood Testing Fingertip capillary blood samples (50 µL and 20 µL, respectively) will be collected to assess oxidative stress using the Clini5 device (Callegari, Italy):
- FORT: Free Oxygen Radical Test
- FORD: Free Oxygen Radical Defence Test These provide an overall assessment of redox status. The device uses rapid, ready-prepared reagents requiring no cooling or manual preparation. Results are available within 6 minutes.
- hs-CRP Capillary Blood Testing A 20 µL fingertip capillary sample will be collected to measure high-sensitivity C-reactive protein (hs-CRP), a marker of systemic inflammation. Analysis will be performed using the Eurolyser Cube S analyser (Eurolyser, Austria), with results available within 5 minutes.
- Perceived Muscle Soreness Participants will report muscle soreness using two validated scales:
- The Visual Analogue Scale (VAS)
- The Borg CR-10 Scale These will be administered at all relevant timepoints.
- Maximal Strength Testing (Cybex Dynamometer) Isokinetic Strength: Peak torque of the knee extensors will be measured at 60°·s-¹ using a Cybex isokinetic dynamometer. This will be completed at all testing timepoints.
- Isometric Mid-Thigh Pull (IMTP) Peak force and rate of force development will be assessed using an isometric mid-thigh pull rig with standardised knee and hip angles. Force production will be recorded via VALD force plates.
- Countermovement Jump (CMJ) Participants will perform countermovement jumps on VALD force plates to assess neuromuscular function. They will complete three warm-up jumps, followed by three recorded trials, with hands placed on the hips to minimise upper-body contribution.
Downhill running protocol Participants will arrive in a fasted state either over night (for morning sessions) or a minimum of four hours fasted (mid-morning, afternoon and evening sessions). Participants will be familiarized with all equipment used and procedures before baseline measurements of height, weight and body composition are taken and pre-test venous blood sample taken. Participants will then complete a five-minute warm-up on a treadmill at 1% gradient at a self-selected speed. Following the warm-up, the treadmill will then be lowered to -10% gradient and participants will run for 45 minutes at 70% of their maximal aerobic capacity.
- Participants will be required to take their assigned supplements daily for a period of four months. During this phase, they will have brief check-ins approximately every four weeks to monitor wellbeing and adherence. At the midpoint of supplementation (two months), a short visit is required for a dried blood spot test (see Figure 1 for an overview of the study timeline).
Although the overall study duration spans several months, data collection involves only nine in-person visits, most of which will last under one hour. Only the main exercise-testing sessions will be longer in duration.
- The research will take part at St Mary's University in the performance Laboratories.
- All testing equipment used is the property of St Mary's University Twickenham. All supplement will be provided by OmegaQuant. All testing procedures are as outlined by British Association of Sport and Exercise Science.
- Conditions
- Focus on Omega 3 Index on Recovery
- Being tested
- Oil Supplementation
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Oil SupplementationDietary supplement
Also called Omega 3, PUFA
We are providing fish oil supplementation with the aim to increase the omega 3 index (O3I) in red blood cells from a low amount (5-6%) to a high amount >8%. The fish oil group will be provided a supplement with a dose of EPA and DHA which is designed for them to get to this level. The placebo group has a supplement which is not designed to increase the EPA + DHA in the blood. After 4 months, the O3I levels in the blood will be checked and if they have reached the appropriate level they will proceed to the next phase which is to complete a muscle damaging protocol specifically down hill running. They will then be assessed on their recovery directly post exercise, 24h, 48h, and 72h post exercise.
| Study group | Role | What they receive |
|---|---|---|
| Fish Oil Group | Experimental | This group will take 4 pills a day of omegaquants parasol fish oil supplementation (https://parasolnutrition.com/product/omega-3-fish-oil/) . This dose will provide 4g a day of total fat and 2.8 g/day of EPA+DHA. The participants will be taking the pills for 4 months and will be instructed to take 2 in the morning and 2 in the evening with meals. Receives: Dietary Supplement: Oil Supplementation |
| Placebo group | Placebo comparator | The placebo group will be taking placebo for 4 months. Similar to the fish oil pill it will be a gelatine capsule however they will be taking refined high-oleic sunflower oil. We aim to match the fish oil group by them taking a total of 4g of fat a day. Receives: Dietary Supplement: Oil Supplementation |
What is being measured
The primary outcome is the main question the study is designed to answer.
Plasma interleukin-6 (IL-6) concentration
Venous blood samples will be collected at baseline (pre-exercise) and during recovery at immediately post-exercise, 24 hours, 48 hours, and 72 hours post-exercise. Samples will be processed to obtain plasma and stored at -80°C in coded tubes to maintain participant confidentiality. After completion of sample collection for all participants, plasma IL-6 concentration will be quantified (e.g., via immunoassay) and reported as concentration at each time point and/or change from baseline.
Measured: Participants will complete this once at baseline and then again after 4 months of supplementation.
Plasma interleukin-10 (IL-10) concentration
Venous blood samples will be collected at baseline (pre-exercise) and during recovery at immediately post-exercise, 24 hours, 48 hours, and 72 hours post-exercise. Samples will be processed to obtain plasma and stored at -80°C in coded tubes to maintain participant confidentiality. After completion of sample collection for all participants, plasma IL-10 concentration will be quantified (e.g., via immunoassay) and reported as concentration at each time point and/or change from baseline.
Measured: Participants will complete this once at baseline and then again after 4 months of supplementation.
Plasma Tumor Necrosis Factor-α (TNF-α) concentration
Venous blood samples will be collected at baseline (pre-exercise) and during recovery at immediately post-exercise, 24 hours, 48 hours, and 72 hours post-exercise. Samples will be processed to obtain plasma and stored at -80°C in coded tubes to maintain participant confidentiality. After completion of sample collection for all participants, plasma TNF-α concentration will be quantified (e.g., via immunoassay) and reported as concentration at each time point and/or change from baseline.
Measured: Participants will complete this once at baseline and then again after 4 months of supplementation.
Myoglobin concentration
Venous blood samples will be collected at baseline (pre-exercise) and during recovery at immediately post-exercise, 24 hours, 48 hours, and 72 hours post-exercise. Samples will be processed to obtain both plasma and serum and stored at -80°C in coded tubes to maintain participant confidentiality. After completion of sample collection for all participants, myoglobin concentration will be quantified (e.g., via immunoassay) and reported as concentration at each time point and/or change from baseline.
Measured: Participants will complete this once at baseline and then again after 4 months of supplementation.
Serum Lactate dehydrogenase (LDH) concentration
Venous blood samples will be collected at baseline (pre-exercise) and during recovery at immediately post-exercise, 24 hours, 48 hours, and 72 hours post-exercise. Samples will be processed to obtain plasma and stored at -80°C in coded tubes to maintain participant confidentiality. After completion of sample collection for all participants, Serum LDH concentration will be quantified (e.g., via immunoassay) and reported as concentration at each time point and/or change from baseline.
Measured: Participants will complete this once at baseline and then again after 4 months of supplementation.
Plasma creatine kinase (CK) concentration
Venous blood samples will be collected at baseline (pre-exercise) and during recovery at immediately post-exercise, 24 hours, 48 hours, and 72 hours post-exercise. Samples will be processed to obtain plasma and stored at -80°C in coded tubes to maintain participant confidentiality. After completion of sample collection for all participants, plasma CK concentration will be quantified (e.g., via immunoassay) and reported as concentration at each time point and/or change from baseline.
Measured: Participants will complete this once at baseline and then again after 4 months of supplementation.
Plasma high sensitivity C-reactive Protein (hs-CRP) concentration
Venous blood samples will be collected at baseline (pre-exercise) and during recovery at immediately post-exercise, 24 hours, 48 hours, and 72 hours post-exercise. Samples will be processed to obtain plasma and stored at -80°C in coded tubes to maintain participant confidentiality. After completion of sample collection for all participants, plasma hs-CRP concentration will be quantified (e.g., via immunoassay) and reported as concentration at each time point and/or change from baseline.
Measured: Participants will complete this once at baseline and then again after 4 months of supplementation.
Capillary Free Oxygen Radical Test (FORT) Concentration
Capillary whole blood samples (20 µL) will be collected at baseline (pre-exercise) and immediately post-exercise from the fingertip or earlobe using a single-use lancet. Oxidative stress will be assessed using the Free Oxygen Radicals Test (FORT) on the Callegari Clini5 analyser; analysis time is approximately 6 minutes. Results will be recorded at each time point and reported as the FORT value and change from baseline.
Measured: Participants will complete this once at baseline and then again after 4 months of supplementation.
Capillary Free Oxygen Radical Defence (FORD) Concentration
Capillary whole blood samples (50 µL) will be collected at baseline (pre-exercise) and immediately post-exercise from the fingertip or earlobe using a single-use lancet. Oxidative stress will be assessed using the Free Oxygen Radical Defence (FORD) on the Callegari Clini5 analyser; analysis time is approximately 6 minutes. Results will be recorded at each time point and reported as the FORT value and change from baseline.
Measured: Participants will complete this once at baseline and then again after 4 months of supplementation.
Secondary outcomes (6)
Muscle soreness (Visual Analogue Scale, VAS)
Participants will complete 5 bodyweight squats, then rate perceived leg muscle soreness using a visual analogue scale (VAS) by placing a mark on a 100-mm line anchored from "no soreness" to "worst soreness imaginable." The score will be recorded in mm (0-100) at each assessment time point and analysed as the VAS value and/or change from baseline.
Measured: Participants will complete this once at baseline and then again after 4 months of supplementation.
Muscle soreness (Borg CR-10 Scale)
Participants will rate perceived exertion using the Borg Category-Ratio 10 (CR-10) scale at baseline (pre-exercise), immediately post-exercise, and during recovery at 24 hours, 48 hours, and 72 hours post-exercise (aligned with venous sampling time points). The CR-10 ranges from 0 ("nothing at all") to 10 ("maximal"), and participants will select the number that best represents their exertion. Scores will be recorded in CR-10 units at each time point and analysed as the value and/or change from baseline.
Measured: Participants will complete this once at baseline and then again after 4 months of supplementation.
Knee extensor strength (isokinetic dynamometry: peak torque at 60°/s)
Peak torque of the knee extensors will be assessed using a Cybex isokinetic dynamometer at an angular velocity of 60°·s-¹. Testing will be performed at all study assessment time points (baseline and post-exercise recovery visits). Peak torque will be recorded in N·m for each assessment and analysed as the value at each time point and/or change from baseline.
Measured: Participants will complete this once at baseline and then again after 4 months of supplementation.
Knee extensor isometric endurance (time to task failure at 50% peak torque)
Knee extensor isometric endurance will be assessed using the Cybex dynamometer. After determination of knee extensor peak torque, participants will perform a sustained isometric contraction at 50% of their isokinetic peak torque and will be instructed to hold the target force/torque for as long as possible. The test will be terminated when the participant can no longer maintain the target (time to task failure). Endurance will be recorded as time (seconds) at each assessment time point and analysed as the value and/or change from baseline.
Measured: Participants will complete this once at baseline and then again after 4 months of supplementation.
Isometric mid-thigh pull (IMTP): peak force and rate of force development
Peak force and rate of force development (RFD) will be assessed using an isometric mid-thigh pull (IMTP) rig. Participants will be positioned in a standardized pulling posture with consistent knee and hip angles across sessions and secured to a fixed bar/rig. After instruction and familiarisation, participants will perform maximal isometric pulls "as hard and as fast as possible" for a fixed duration, with trials separated by standardized rest periods. Ground reaction forces will be recorded using VALD force plates, and outcomes will be derived as peak force (N) and RFD (e.g., N·s-¹) at each testing time point and/or change from baseline.
Measured: Participants will complete this once at baseline and then again after 4 months of supplementation.
Countermovement jump (CMJ): jump performance
Countermovement jump performance will be assessed using VALD force plates. Participants will perform standardized CMJs (e.g., hands on hips) from an upright standing position, completing a rapid downward countermovement followed immediately by a maximal vertical jump. Trials will be separated by standardized rest periods, and force-time data will be recorded for each jump. Outcomes will be derived from the force-plate data (e.g., jump height and/or peak power/peak force, as specified) at each testing time point and/or change from baseline.
Measured: Participants will complete this once at baseline and then again after 4 months of supplementation.
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted27 Feb 2026
- Study start28 Feb 2026 (estimated)
- Primary completion30 Dec 2027 (estimated)
- Study completion30 Dec 2028 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Focus on Omega 3 Index on RecoveryStudies 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
- Parallel groups
- Masking
- Double blind
- Who is masked
- Investigator, Outcomes assessor
- Enrolment
- 46 participants (estimated)
Sponsor and investigators
- Lead sponsor
- St. Mary's University, Twickenham
- Sponsor type
- University, hospital or other
- Responsible party
- Sponsor
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07439601
- Sponsor's protocol ID
- SMU_ETHICS_2025-26_198
- Acronym
- IMPROVE-8
- Status last verified
- Feb 2026
- First submitted
- 6 Feb 2026
- Last updated
- 27 Feb 2026
- Results posted
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- No: Individual participant data will not be made publicly available because the dataset contains sensitive health/biological measures collected repeatedly over time, and the combination of variables may allow re-identification in a relatively small cohort. Data sharing beyond the study team is not covered by the current consent and ethics approval, and unrestricted release would conflict with institutional and legal privacy requirements.
Study at a glance
From the registry record, last updated by the sponsor on 27 Feb 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- The Impact of Long-term Omega-3 Supplementation and an Omega-3 Index Above 8% on Physiological Recovery Following Exercise-Induced Muscle Damage
- ClinicalTrials.gov ID
- NCT07439601
- Acronym / sponsor ID
- IMPROVE-8 / SMU_ETHICS_2025-26_198
- Conditions
- Focus on Omega 3 Index on Recovery
- Study type
- Interventional
- Recruitment status
- Not yet recruiting
- Enrolment
- 46 participants (estimated)
- Lead sponsor
- St. Mary's University, TwickenhamUniversity, hospital or other
- Study start
- 28 Feb 2026 (estimated)
- Primary completion
- 30 Dec 2027 (estimated)
- Study completion
- 30 Dec 2028 (estimated)
- First posted
- 27 Feb 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.
The Omega-3 Index measures how much of the Omega-3 fats EPA and DHA are built into red blood cell membranes. These fats are essential for health, but the body cannot make enough of them, so they must come from foods like oily fish or from supplements. The Index reflects long-term Omega-3 intake and is considered optimal at 8% or higher. Levels below this range have been linked with poorer cardiovascular health (Harris \& Von Schacky, 2004).
. For athletes, Omega-3 research suggests they can help reduce inflammation, ease muscle soreness, and support immune function. Despite this, many elite athletes appear to have Omega-3 Index values around 4-5%, well below the recommended level of 8%.
Therefore, the aim of this study is to investigate whether increasing the Omega-3 index has any recovery benefits post a bout of downhill running in athletes. Downhill running is commonly used as way to cause exercise-induced muscle damage and study recovery. The Omega-3 index will be increased with a daily fish oil supplement.
Detailed description
The proposed research will follow quantitative methods using a randomized independent-groups design. Participants will be allocated to one of two conditions: a placebo group or a fish oil supplementation group. All testing will take place in the St. Mary's University Performance Labs.
Screening and Eligibility
At the initial visit, participants will provide informed consent and complete a PAR-Q form. Eligibility screening will include confirmation that participants have an Omega-3 index ≤ 5%, assessed via a dried blood spot sample obtained from a capillary finger-prick. Samples are processed by OmegaQuant at their lab in Stirling, and results are typically returned within one week.
Participants will also be excluded if they are currently consuming ≥1 g/day of fish-oil supplements.
Randomisation and Blinding
Eligible participants will be randomly assigned to one of the two experimental groups using a random number generator (https://www.random.org). The study will follow a double-blind design: participants will not know which supplement they receive, and the primary investigators involved in data collection will also remain blinded. Supplement distribution and any dose adjustments will be conducted by a separate member of the research team who is unblinded and not involved in testing of participants or data analysis.
Screening Tests/familiarisation
Once Omega-3 index results are available, eligible participants will return to the lab for physiological screening/familiarisation of the test battery and to receive their supplements. Screening/familiarisation procedures include:
- An incremental treadmill ramp test, starting at 8 km·h-¹ and increasing by 1 km·h-¹ every 3 minutes until volitional exhaustion. During the test the below measures will be taken:
- Capillary blood lactate sampling (finger or earlobe) every 3 minutes.
- Continuous breath-by-breath respiratory analysis using the Vyntus online gas analyser.
- Heart rate monitoring (Polar H10) and Rate of Perceived Exertion (RPE; Borg scale).
The screening session also introduces participants to the test battery illustrated in Figure 3.
Supplementation Phase (Part A)
Participants will be asked to refrain from:
- Alcohol for 48 hours before each testing session.
- Caffeine for 12 hours before each testing session.
Participants will consume their assigned supplements daily for four months. Investigators will contact participants approximately every four weeks to assess adherence and to distribute additional supplement supplies.
At two months, a repeat dried blood spot sample will assess whether Omega-3 levels in the fish-oil group are increasing as expected. If required, supplementation will be adjusted using the OmegaQuant calculator (https://omegaquant.com/omega-3-index-calculator/). Adjustments will typically involve changes of approximately 0.5 g/day (EPA + DHA).
To maintain double-blinding, placebo dosages will also be altered by ±0.5 g/day, ensuring both investigator and participant remain unaware of group allocation.
After four months, participants will provide another dried blood sample. The aim is for the fish-oil group to reach an Omega-3 index ≥ 8%. Participants who do not meet their target will continue supplementation for an additional 2-4 weeks, followed by another blood test, until the required level is achieved. A cut-off point 6 additional weeks will be incorporated.
Completion of this phase constitutes Part A: the supplementation phase. Exercise-Induced Muscle Damage Trial (Part B) Approximately one week before Part B, participants will return to the lab to complete a second treadmill ramp test to determine the appropriate speed for the downhill running protocol.
Participants will then attend the laboratory on four consecutive days to complete pre- and post-exercise assessments associated with the exercise-induced muscle damage protocol.
The proposed study requires participants to take fish oil supplementation in order to increase their Omega-3 index and investigate whether this produces performance or recovery benefits, beyond the well-established long-term health effects associated with approximately 3 g/day of EPA + DHA. Fish oil supplementation is widely used in both clinical and general health contexts and is considered safe at doses of up to 5 g/day, as recognised by the European Food Safety Authority.
Participants will be recruited to complete the supplementation phase and take part in an exercise-induced muscle damage (EIMD) protocol. They will be randomly allocated to one of the two study groups (fish oil or placebo).
Fish oil supplementation will be provided by OmegaQuant (https://parasolnutrition.com/product/omega-3-fish-oil/) , this supplement is commercially available
Test battery:
- Venous Blood Samples Venous blood samples will be collected to assess resting concentrations of inflammatory and muscle-damage biomarkers, including Interleukin-6 (IL-6), Interleukin-10 (IL-10), Tumor Necrosis Factor-α (TNF-α), myoglobin, lactate dehydrogenase (LDH), and creatine kinase (CK). Samples will be obtained by qualified phlebotomists at St Mary's University (Toby Helder, Prof. Charles Pedlar, and Dr Jessica Hill). All venous samples will be stored at -80°C and later analysed using enzyme-linked immunosorbent assays (ELISAs). Venous sampling will occur at all required testing timepoints.
- FORD/FORT Capillary Blood Testing Fingertip capillary blood samples (50 µL and 20 µL, respectively) will be collected to assess oxidative stress using the Clini5 device (Callegari, Italy):
- FORT: Free Oxygen Radical Test
- FORD: Free Oxygen Radical Defence Test These provide an overall assessment of redox status. The device uses rapid, ready-prepared reagents requiring no cooling or manual preparation. Results are available within 6 minutes.
- hs-CRP Capillary Blood Testing A 20 µL fingertip capillary sample will be collected to measure high-sensitivity C-reactive protein (hs-CRP), a marker of systemic inflammation. Analysis will be performed using the Eurolyser Cube S analyser (Eurolyser, Austria), with results available within 5 minutes.
- Perceived Muscle Soreness Participants will report muscle soreness using two validated scales:
- The Visual Analogue Scale (VAS)
- The Borg CR-10 Scale These will be administered at all relevant timepoints.
- Maximal Strength Testing (Cybex Dynamometer) Isokinetic Strength: Peak torque of the knee extensors will be measured at 60°·s-¹ using a Cybex isokinetic dynamometer. This will be completed at all testing timepoints.
- Isometric Mid-Thigh Pull (IMTP) Peak force and rate of force development will be assessed using an isometric mid-thigh pull rig with standardised knee and hip angles. Force production will be recorded via VALD force plates.
- Countermovement Jump (CMJ) Participants will perform countermovement jumps on VALD force plates to assess neuromuscular function. They will complete three warm-up jumps, followed by three recorded trials, with hands placed on the hips to minimise upper-body contribution.
Downhill running protocol Participants will arrive in a fasted state either over night (for morning sessions) or a minimum of four hours fasted (mid-morning, afternoon and evening sessions). Participants will be familiarized with all equipment used and procedures before baseline measurements of height, weight and body composition are taken and pre-test venous blood sample taken. Participants will then complete a five-minute warm-up on a treadmill at 1% gradient at a self-selected speed. Following the warm-up, the treadmill will then be lowered to -10% gradient and participants will run for 45 minutes at 70% of their maximal aerobic capacity.
- Participants will be required to take their assigned supplements daily for a period of four months. During this phase, they will have brief check-ins approximately every four weeks to monitor wellbeing and adherence. At the midpoint of supplementation (two months), a short visit is required for a dried blood spot test (see Figure 1 for an overview of the study timeline).
Although the overall study duration spans several months, data collection involves only nine in-person visits, most of which will last under one hour. Only the main exercise-testing sessions will be longer in duration.
- The research will take part at St Mary's University in the performance Laboratories.
- All testing equipment used is the property of St Mary's University Twickenham. All supplement will be provided by OmegaQuant. All testing procedures are as outlined by British Association of Sport and Exercise Science.
Study design
- Primary purpose
- Other
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Double blind (investigator, outcomes assessor)
- Number of arms
- 2
| Arm | Type | Receives |
|---|---|---|
| Fish Oil Group | Experimental | Dietary Supplement: Oil SupplementationThis group will take 4 pills a day of omegaquants parasol fish oil supplementation (https://parasolnutrition.com/product/omega-3-fish-oil/) . This dose will provide 4g a day of total fat and 2.8 g/day of EPA+DHA. The participants will be taking the pills for 4 months and will be instructed to take 2 in the morning and 2 in the evening with meals. |
| Placebo group | Placebo comparator | Dietary Supplement: Oil SupplementationThe placebo group will be taking placebo for 4 months. Similar to the fish oil pill it will be a gelatine capsule however they will be taking refined high-oleic sunflower oil. We aim to match the fish oil group by them taking a total of 4g of fat a day. |
Who may qualify
- Ages
- 18 to 50 years
- Sex
- All
- Healthy volunteers
- Accepted
- Age groups
- Adult
Key inclusion criteria (4 listed)
- An Omega-3 index of ≤ 6%
- Age 18-50 years
- Sub-elite to elite athletes from local sports teams (e.g. cycling, triathlon)
- Male and female
Key exclusion criteria (1 listed)
- inflammatory diseases, injuries that prevent them exercising.
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 |
|---|---|---|
| Oil SupplementationAlso: Omega 3, PUFAWe are providing fish oil supplementation with the aim to increase the omega 3 index (O3I) in red blood cells from a low amount (5-6%) to a high amount >8%. The fish oil group will be provided a supplement with a dose of EPA and DHA which is designed for them to get to this level. The placebo group has a supplement which is not designed to increase the EPA + DHA in the blood. After 4 months, the O3I levels in the blood will be checked and if they have reached the appropriate level they will proceed to the next phase which is to complete a muscle damaging protocol specifically down hill running. They will then be assessed on their recovery directly post exercise, 24h, 48h, and 72h post exercise. | Dietary supplement | Fish Oil Group, Placebo group |
Primary outcome
Plasma interleukin-6 (IL-6) concentration
Time frame: Participants will complete this once at baseline and then again after 4 months of supplementation.
Venous blood samples will be collected at baseline (pre-exercise) and during recovery at immediately post-exercise, 24 hours, 48 hours, and 72 hours post-exercise. Samples will be processed to obtain plasma and stored at -80°C in coded tubes to maintain participant confidentiality. After completion of sample collection for all participants, plasma IL-6 concentration will be quantified (e.g., via immunoassay) and reported as concentration at each time point and/or change from baseline.
Plasma interleukin-10 (IL-10) concentration
Time frame: Participants will complete this once at baseline and then again after 4 months of supplementation.
Venous blood samples will be collected at baseline (pre-exercise) and during recovery at immediately post-exercise, 24 hours, 48 hours, and 72 hours post-exercise. Samples will be processed to obtain plasma and stored at -80°C in coded tubes to maintain participant confidentiality. After completion of sample collection for all participants, plasma IL-10 concentration will be quantified (e.g., via immunoassay) and reported as concentration at each time point and/or change from baseline.
Plasma Tumor Necrosis Factor-α (TNF-α) concentration
Time frame: Participants will complete this once at baseline and then again after 4 months of supplementation.
Venous blood samples will be collected at baseline (pre-exercise) and during recovery at immediately post-exercise, 24 hours, 48 hours, and 72 hours post-exercise. Samples will be processed to obtain plasma and stored at -80°C in coded tubes to maintain participant confidentiality. After completion of sample collection for all participants, plasma TNF-α concentration will be quantified (e.g., via immunoassay) and reported as concentration at each time point and/or change from baseline.
Myoglobin concentration
Time frame: Participants will complete this once at baseline and then again after 4 months of supplementation.
Venous blood samples will be collected at baseline (pre-exercise) and during recovery at immediately post-exercise, 24 hours, 48 hours, and 72 hours post-exercise. Samples will be processed to obtain both plasma and serum and stored at -80°C in coded tubes to maintain participant confidentiality. After completion of sample collection for all participants, myoglobin concentration will be quantified (e.g., via immunoassay) and reported as concentration at each time point and/or change from baseline.
Serum Lactate dehydrogenase (LDH) concentration
Time frame: Participants will complete this once at baseline and then again after 4 months of supplementation.
Venous blood samples will be collected at baseline (pre-exercise) and during recovery at immediately post-exercise, 24 hours, 48 hours, and 72 hours post-exercise. Samples will be processed to obtain plasma and stored at -80°C in coded tubes to maintain participant confidentiality. After completion of sample collection for all participants, Serum LDH concentration will be quantified (e.g., via immunoassay) and reported as concentration at each time point and/or change from baseline.
Plasma creatine kinase (CK) concentration
Time frame: Participants will complete this once at baseline and then again after 4 months of supplementation.
Venous blood samples will be collected at baseline (pre-exercise) and during recovery at immediately post-exercise, 24 hours, 48 hours, and 72 hours post-exercise. Samples will be processed to obtain plasma and stored at -80°C in coded tubes to maintain participant confidentiality. After completion of sample collection for all participants, plasma CK concentration will be quantified (e.g., via immunoassay) and reported as concentration at each time point and/or change from baseline.
Plasma high sensitivity C-reactive Protein (hs-CRP) concentration
Time frame: Participants will complete this once at baseline and then again after 4 months of supplementation.
Venous blood samples will be collected at baseline (pre-exercise) and during recovery at immediately post-exercise, 24 hours, 48 hours, and 72 hours post-exercise. Samples will be processed to obtain plasma and stored at -80°C in coded tubes to maintain participant confidentiality. After completion of sample collection for all participants, plasma hs-CRP concentration will be quantified (e.g., via immunoassay) and reported as concentration at each time point and/or change from baseline.
Capillary Free Oxygen Radical Test (FORT) Concentration
Time frame: Participants will complete this once at baseline and then again after 4 months of supplementation.
Capillary whole blood samples (20 µL) will be collected at baseline (pre-exercise) and immediately post-exercise from the fingertip or earlobe using a single-use lancet. Oxidative stress will be assessed using the Free Oxygen Radicals Test (FORT) on the Callegari Clini5 analyser; analysis time is approximately 6 minutes. Results will be recorded at each time point and reported as the FORT value and change from baseline.
Capillary Free Oxygen Radical Defence (FORD) Concentration
Time frame: Participants will complete this once at baseline and then again after 4 months of supplementation.
Capillary whole blood samples (50 µL) will be collected at baseline (pre-exercise) and immediately post-exercise from the fingertip or earlobe using a single-use lancet. Oxidative stress will be assessed using the Free Oxygen Radical Defence (FORD) on the Callegari Clini5 analyser; analysis time is approximately 6 minutes. Results will be recorded at each time point and reported as the FORT value and change from baseline.
6 secondary outcomes
Muscle soreness (Visual Analogue Scale, VAS)
Time frame: Participants will complete this once at baseline and then again after 4 months of supplementation.
Muscle soreness (Borg CR-10 Scale)
Time frame: Participants will complete this once at baseline and then again after 4 months of supplementation.
Knee extensor strength (isokinetic dynamometry: peak torque at 60°/s)
Time frame: Participants will complete this once at baseline and then again after 4 months of supplementation.
Knee extensor isometric endurance (time to task failure at 50% peak torque)
Time frame: Participants will complete this once at baseline and then again after 4 months of supplementation.
Isometric mid-thigh pull (IMTP): peak force and rate of force development
Time frame: Participants will complete this once at baseline and then again after 4 months of supplementation.
Countermovement jump (CMJ): jump performance
Time frame: Participants will complete this once at baseline and then again after 4 months of supplementation.
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 27 Feb 2026.
- Individual participant dataSharing planned: No. Individual participant data will not be made publicly available because the dataset contains sensitive health/biological measures collected repeatedly over time, and the combination of variables may allow re-identification in a relatively small cohort. Data sharing beyond the study team is not covered by the current consent and ethics approval, and unrestricted release would conflict with institutional and legal privacy requirements.
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.
Questions about this trial
What is this clinical trial studying?
A study testing Oil Supplementation in people with Focus on Omega 3 Index on Recovery, run by St. Mary's University, Twickenham.
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 4 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: opening soon, as of the sponsor's last update on 27 Feb 2026. Status can change between updates, so confirm with the study contact before making plans.
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?
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 Toby A Helder (+44 943571550, toby.helder@stmarys.ac.uk), or a site near the patient. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Plasma interleukin-6 (IL-6) concentration (time frame: Participants will complete this once at baseline and then again after 4 months of supplementation.). 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 27 Feb 2026; AzTrials last refreshed its copy on 6 Nov 2026.