Creatine Absorption in Healthy AdultsNCT07225335
Impact of OptiCreatine on Plasma Creatine and Gastrointestinal Effects in Males and Females
A study testing OptiCreatine and Creatine Monohydrate in people with Creatine Absorption in Healthy Adults, run by TSI Group LTD at 1 site in United States.
Trial summary
The study aims to evaluate the novel OptiCreatine formulation, which combines creatine with other bioactive compounds purported to enhance absorption and reduce gastrointestinal (GI) discomfort. Read more about this study
- Who is it for?
- Ages 18 to 45 yearsHealthy volunteers can take part
- Conditions the study is for
- Creatine Absorption in Healthy Adults
- What is being tested?
- OptiCreatine and Creatine Monohydrate
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 17 participants
- Where
- 1 siteUnited States
- Study dates
- 5 Nov 2025to 19 Dec 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 45 years
- All sexes
- Healthy volunteers accepted
- Adult
Who may be able to join
- Adults between the ages of 18-45 yrs
- Body mass index of <35 kg/m2
- Recreationally active [≥30 minutes of moderate-intensity physical activity per week as defined by the International Physical Activity Questionnaire (IPAQ)]
- Participant is healthy and free from disease as determined by a health history questionnaire.
- Participant agrees to abstain from caffeine (24 hrs. prior), tobacco (24 hrs. prior), and alcohol (24 hrs. prior) before testing days
Who cannot join
- Has chronic kidney disease, liver disease, chronic obstructive pulmonary disease, or cancer
- Currently using medications that may directly impact the primary outcomes including: diuretics and corticosteroids)
- Currently using creatine monohydrate
- Has severely impaired hearing or speech or inability to speak English
Trial locations and contacts
1 site in 1 country.
United States1 site
Applied Physiology Laboratory (Fetzer Hall, Room 025)
Chapel Hill, North Carolina, 27599-8700
About this study
The study aims to evaluate the novel OptiCreatine formulation, which combines creatine with other bioactive compounds purported to enhance absorption and reduce gastrointestinal (GI) discomfort. Using a randomized, double-blind, crossover design, the study will compare the acute and chronic effects of OptiCreatine versus Creatine monohydrate in healthy, recreationally active adults. Participants will be asked to orally consume both the OptiCreatine and the creatine monohydrate. Primary outcomes include plasma creatine concentrations, gastrointestinal symptomatology, and fluid distribution measured through bioelectrical impedance spectroscopy.
Read the detailed description
The study aims to evaluate the novel OptiCreatine formulation, which combines creatine with other bioactive compounds purported to enhance absorption and reduce gastrointestinal (GI) discomfort. The study objectives are as follows:
- Aim 1: To examine the acute effects of OptiCreatine compared to creatine monohydrate on plasma creatine concentrations and gastrointestinal symptoms.
- Aim 2: To example the effects of 5-days of creatine loading with OptiCreatine compared to creatine monohydrate on gastrointestinal symptoms and fluid distribution.
General Design: All data collection will be completed by the Principal Investigator and Research Assistants at the University of North Carolina. Participants will be asked to report to the Applied Physiology Laboratory and Human Performance Center for enrollment and testing sessions. Thirty-two individuals total will be enrolled into the study. Sixteen participants will be enrolled into the acute phase; Sixteen will be enrolled into the chronic phase with random assignment to OptiCreatine (n=8) or creatine monohydrate (n=8). Participants from the acute phase are eligible to enroll into the chronic phase. The acute phase will require 2 in person visits, in random order, with participants randomly assigned in a cross-over fashion to OptiCreatine vs creatine monohydrate. Blood samples will be obtained at baseline and at 0.5, 1, 1.5, 2, 3, 4, and 5 hrs. following ingestion of the assigned treatment. A minimum of 72 hrs. will take place in between acute visits. For the chronic phase, participants will complete baseline assessments for GI symptoms via questionnaires (bloating questionnaire, gastrointestinal symptom rating scale, digestion associated quality of life questionnaire) and fluid distribution from multi-frequency bioelectrical impedance analysis (MF-BIA). Following baseline testing, participants will be randomly assigned to an OptiCreatine or creatine monohydrate group. Post testing evaluation will occur within 48 hours of the 5-day loading phase.
Supplementation Phase:
- Acute: In a randomized double-blind, cross-over design study, participants will be randomly assigned using a using a computer-generated randomization scheme to consume either OptiCreatine (5 g + 6 oz water, n=8) or creatine monohydrate supplement (5 g + 6 oz water, n=8). All participants will complete both treatments, including a minimum of a 3-day washout period.
- Chronic: In a randomized double-blind design study, participants will be randomly assigned using block randomization in a 1:1 fashion using a computer generation randomization scheme to participants in a creatine loading dose (4 x 5 grams daily- 20 g per day for 5 days) of OptiCreatine or creatine monohydrate.
Participants will be asked to arrive at the laboratory for all visits after a minimum 8-hour fast from caloric foods and beverages, 48-hour abstention from vigorous exercise, and 24-hour abstention from caffeine consumption. Participants will be asked to maintain normal dietary intake along with no more than 200mg of caffeine per day for the duration of the study. Measurements of anthropometrics, GI symptoms, and fluid distribution will be obtained. For the acute phase, blood samples will be taken from the antecubital region.
- Conditions
- Creatine Absorption in Healthy Adults
- Being tested
- OptiCreatine, Creatine Monohydrate
- Keywords
- Absorption, creatine, Healthy adults
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
OptiCreatineDietary supplement
OptiCreatine is a formulation, which combines creatine with other bioactive compounds purported to enhance absorption.
Creatine MonohydrateDietary supplement
Creatine monohydrate (Creapure®)
| Study group | Role | What they receive |
|---|---|---|
| OptiCreatine | Experimental | Combines creatine with other bioactive compounds purported to enhance absorption. Receives: Dietary Supplement: OptiCreatine |
| Creatine monohydrate | Active comparator | Not described Receives: Dietary Supplement: Creatine Monohydrate |
What is being measured
The primary outcome is the main question the study is designed to answer.
Pharmacokinetic Outcomes: Concentration maximum (Cmax)
the maximum observed plasma concentration (Cmax)
Measured: Over a period of 5 hrs. post dose of creatine
Pharmacokinetic Outcomes: Time to concentration maximum (Tmax)
The time to reach the maximum observed plasma concentration
Measured: Over a period of 5 hrs. post dose of creatine
Pharmacokinetic Outcomes: Area Under the Curve (AUC)
The area under the concentration-time curve (AUC)
Measured: Over a period of 5 hrs. post dose of creatine
Secondary outcomes (3)
Digestion-associated Quality of Life Questionnaire (DQLQ) assessment
Digestion-associated Quality of Life Questionnaire (DQLQ) will be assessed on a scale of 0% to 100% at baseline and 6 days, with 0% indicating no effect (never) on digestion-associated quality of life to 90%-100% (always effecting digestion-associated Quality of Life)
Measured: 6 days
Self-perception questionnaire for assessment of bloating
Assessment of bloating using a self-perception questionnaire on a scale of None (no bloating) to very severe (severe bloating) will be conducted at the 1st study visit (baseline), at the 2nd study visit (6 days) after 5 days of creatine loading.
Measured: 6 days
Gastrointestinal Symptom Rating Scale (GSRS)
Gastrointestinal Symptom Rating Scale (GSRS) will be conducted at the 1st study visit (baseline), at the 2nd study visit (6 days) after 5 days of creatine loading. The GSRS is a disease-specific instrument of 15 items combined into five symptom clusters depicting Reflux, Abdominal pain, Indigestion, Diarrhea and Constipation. The GSRS has a seven-point graded Likert-type scale where 1 represents absence of troublesome symptoms and 7 represents very troublesome symptoms.
Measured: 6 days
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted6 Nov 2025
- Study start5 Nov 2025
- Primary completion19 Dec 2025
- Study completion19 Dec 2025
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Creatine Absorption in Healthy AdultsStudies of the same condition, open and under way.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase N/A
- Primary purpose
- Basic science
- Allocation
- Randomised
- Intervention model
- Crossover
- Model description
- Acute: In a randomized double-blind, cross-over design, participants will be randomly assigned using a using a computer-generated randomization scheme to consume either OptiCreatine or creatine monohydrate supplement. All participants will complete both treatments, including a minimum of a 3-day washout period. Chronic: In a randomized double-blind design, participants will be randomly assigned using block randomization in a 1:1 fashion to participants in a creatine loading dose of OptiCreatine or creatine monohydrate.
- Masking
- Double blind
- Who is masked
- Participant, Investigator
- Enrolment
- 17 participants (actual)
Sponsor and investigators
- Lead sponsor
- TSI Group LTD
- Sponsor type
- Industry (pharma, biotech, devices)
- Collaborators
- University of North Carolina
- Responsible party
- Sponsor
- Investigators
- John A Rathmacher, Ph.D., Study director, TSI Group LTD
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07225335
- Sponsor's protocol ID
- 25-2972
- Status last verified
- Mar 2026
- First submitted
- 3 Nov 2025
- Last updated
- 12 Mar 2026
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- No
Study at a glance
From the registry record, last updated by the sponsor on 12 Mar 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Impact of OptiCreatine on Plasma Creatine and Gastrointestinal Effects in Males and Females
- ClinicalTrials.gov ID
- NCT07225335
- Acronym / sponsor ID
- 25-2972
- Conditions
- Creatine Absorption in Healthy Adults
- Keywords
- Absorption, creatine, Healthy adults
- Study type
- Interventional
- Recruitment status
- Completed
- Enrolment
- 17 participants (actual)
- Lead sponsor
- TSI Group LTDIndustry (pharma, biotech, devices)
- Collaborators
- University of North Carolina
- Study start
- 5 Nov 2025 (actual)
- Primary completion
- 19 Dec 2025 (actual)
- Study completion
- 19 Dec 2025 (actual)
- First posted
- 6 Nov 2025 (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 study aims to evaluate the novel OptiCreatine formulation, which combines creatine with other bioactive compounds purported to enhance absorption and reduce gastrointestinal (GI) discomfort. Using a randomized, double-blind, crossover design, the study will compare the acute and chronic effects of OptiCreatine versus Creatine monohydrate in healthy, recreationally active adults. Participants will be asked to orally consume both the OptiCreatine and the creatine monohydrate. Primary outcomes include plasma creatine concentrations, gastrointestinal symptomatology, and fluid distribution measured through bioelectrical impedance spectroscopy.
Detailed description
The study aims to evaluate the novel OptiCreatine formulation, which combines creatine with other bioactive compounds purported to enhance absorption and reduce gastrointestinal (GI) discomfort. The study objectives are as follows:
- Aim 1: To examine the acute effects of OptiCreatine compared to creatine monohydrate on plasma creatine concentrations and gastrointestinal symptoms.
- Aim 2: To example the effects of 5-days of creatine loading with OptiCreatine compared to creatine monohydrate on gastrointestinal symptoms and fluid distribution.
General Design: All data collection will be completed by the Principal Investigator and Research Assistants at the University of North Carolina. Participants will be asked to report to the Applied Physiology Laboratory and Human Performance Center for enrollment and testing sessions. Thirty-two individuals total will be enrolled into the study. Sixteen participants will be enrolled into the acute phase; Sixteen will be enrolled into the chronic phase with random assignment to OptiCreatine (n=8) or creatine monohydrate (n=8). Participants from the acute phase are eligible to enroll into the chronic phase. The acute phase will require 2 in person visits, in random order, with participants randomly assigned in a cross-over fashion to OptiCreatine vs creatine monohydrate. Blood samples will be obtained at baseline and at 0.5, 1, 1.5, 2, 3, 4, and 5 hrs. following ingestion of the assigned treatment. A minimum of 72 hrs. will take place in between acute visits. For the chronic phase, participants will complete baseline assessments for GI symptoms via questionnaires (bloating questionnaire, gastrointestinal symptom rating scale, digestion associated quality of life questionnaire) and fluid distribution from multi-frequency bioelectrical impedance analysis (MF-BIA). Following baseline testing, participants will be randomly assigned to an OptiCreatine or creatine monohydrate group. Post testing evaluation will occur within 48 hours of the 5-day loading phase.
Supplementation Phase:
- Acute: In a randomized double-blind, cross-over design study, participants will be randomly assigned using a using a computer-generated randomization scheme to consume either OptiCreatine (5 g + 6 oz water, n=8) or creatine monohydrate supplement (5 g + 6 oz water, n=8). All participants will complete both treatments, including a minimum of a 3-day washout period.
- Chronic: In a randomized double-blind design study, participants will be randomly assigned using block randomization in a 1:1 fashion using a computer generation randomization scheme to participants in a creatine loading dose (4 x 5 grams daily- 20 g per day for 5 days) of OptiCreatine or creatine monohydrate.
Participants will be asked to arrive at the laboratory for all visits after a minimum 8-hour fast from caloric foods and beverages, 48-hour abstention from vigorous exercise, and 24-hour abstention from caffeine consumption. Participants will be asked to maintain normal dietary intake along with no more than 200mg of caffeine per day for the duration of the study. Measurements of anthropometrics, GI symptoms, and fluid distribution will be obtained. For the acute phase, blood samples will be taken from the antecubital region.
Study design
- Primary purpose
- Basic science
- Allocation
- Randomised
- Intervention model
- Crossover
- Masking
- Double blind (participant, investigator)
- Number of arms
- 2
- Model description
- Acute: In a randomized double-blind, cross-over design, participants will be randomly assigned using a using a computer-generated randomization scheme to consume either OptiCreatine or creatine monohydrate supplement. All participants will complete both treatments, including a minimum of a 3-day washout period. Chronic: In a randomized double-blind design, participants will be randomly assigned using block randomization in a 1:1 fashion to participants in a creatine loading dose of OptiCreatine or creatine monohydrate.
| Arm | Type | Receives |
|---|---|---|
| OptiCreatine | Experimental | Dietary Supplement: OptiCreatineCombines creatine with other bioactive compounds purported to enhance absorption. |
| Creatine monohydrate | Active comparator | Dietary Supplement: Creatine Monohydrate |
Who may qualify
- Ages
- 18 to 45 years
- Sex
- All
- Healthy volunteers
- Accepted
- Age groups
- Adult
Key inclusion criteria (5 listed)
- Adults between the ages of 18-45 yrs
- Body mass index of <35 kg/m2
- Recreationally active [≥30 minutes of moderate-intensity physical activity per week as defined by the International Physical Activity Questionnaire (IPAQ)]
- Participant is healthy and free from disease as determined by a health history questionnaire.
- Participant agrees to abstain from caffeine (24 hrs. prior), tobacco (24 hrs. prior), and alcohol (24 hrs. prior) before testing days
Key exclusion criteria (4 listed)
- Has chronic kidney disease, liver disease, chronic obstructive pulmonary disease, or cancer
- Currently using medications that may directly impact the primary outcomes including: diuretics and corticosteroids)
- Currently using creatine monohydrate
- Has severely impaired hearing or speech or inability to speak English
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 |
|---|---|---|
| OptiCreatineOptiCreatine is a formulation, which combines creatine with other bioactive compounds purported to enhance absorption. | Dietary supplement | OptiCreatine |
| Creatine MonohydrateCreatine monohydrate (Creapure®) | Dietary supplement | Creatine monohydrate |
Primary outcome
Pharmacokinetic Outcomes: Concentration maximum (Cmax)
Time frame: Over a period of 5 hrs. post dose of creatine
the maximum observed plasma concentration (Cmax)
Pharmacokinetic Outcomes: Time to concentration maximum (Tmax)
Time frame: Over a period of 5 hrs. post dose of creatine
The time to reach the maximum observed plasma concentration
Pharmacokinetic Outcomes: Area Under the Curve (AUC)
Time frame: Over a period of 5 hrs. post dose of creatine
The area under the concentration-time curve (AUC)
3 secondary outcomes
Digestion-associated Quality of Life Questionnaire (DQLQ) assessment
Time frame: 6 days
Self-perception questionnaire for assessment of bloating
Time frame: 6 days
Gastrointestinal Symptom Rating Scale (GSRS)
Time frame: 6 days
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 12 Mar 2026.
- Individual participant dataSharing planned: No
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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.
John A Rathmacher, Ph.D. study director
TSI Group LTD
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing OptiCreatine and Creatine Monohydrate in people with Creatine Absorption in Healthy Adults, run by TSI Group LTD 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 5 inclusion and 4 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 12 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 United States. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
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?
Pharmacokinetic Outcomes: Concentration maximum (Cmax) (time frame: Over a period of 5 hrs. post dose of creatine). The study lists 3 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 12 Mar 2026.