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Trial registered on ANZCTR


Registration number
Help: Registration number
ACTRN12626000247370
Ethics application status
Help: Ethics application status
Approved
Date submitted
Help: Date submitted
27/01/2026
Date registered
Help: Date registered
27/02/2026
Date last updated
Help: Date last updated
27/02/2026
Date data sharing statement initially provided
Help: Data sharing statement date
27/02/2026
Type of registration
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Prospectively registered

Titles & IDs
Public title
Evaluating the Effect of Hydrogel Encapsulated Sodium Bicarbonate on Exercise Tolerance in Healthy Adults
Scientific title
Evaluating the Effect of Hydrogel Encapsulated Sodium Bicarbonate on Exercise Tolerance in Healthy Adults
Additional trial identifiers [1] 316321 0
None
Universal Trial Number (UTN)
Trial acronym
Related trial records

Health condition
Health condition(s) studied:
Physical fatigue 340379 0
Condition category
Condition code
Musculoskeletal 336756 336756 0 0
Normal musculoskeletal and cartilage development and function

Intervention/exposure
Study type
Interventional
Description of the intervention or exposure
The research comprises a randomised double-blind placebo-controlled trial to evaluate the safety, tolerability, and physiological effects of a hydrogel-encapsulated sodium bicarbonate formulation co-delivered with caffeine and carbohydrates. The study seeks to establish whether this intervention improves exercise tolerance and mitigates symptoms of fatigue.


Phase 1 will involve 16 healthy adults (8 per intervention and control group). Participants will complete two test visits at the laboratory in the Flinders University Health and Medicine Research building. During the first visit participants will undertake a cycling based exercise test (INSCYD lactate test) to define baseline exercise tolerance. During the second visit, 96 hours later, they will orally ingest either an active hydrogel formulation containing 0.25 g/kg of body mass of sodium bicarbonate (90 min pre-exercise), as well as 100 mg caffeine and 25 g of carbohydrate (45 min pre-exercise) before undertaking the same INSCYD lactate test. To ensure adherence, treatment ingestion will occur under researcher supervision. Physiological responses will be assessed using capillary lactate sampling, venous blood gas analysis, and subjective effort ratings. Tolerability will be evaluated using gastrointestinal distress symptom questionnaires, palatability scores, and protocol adherence.
Intervention code [1] 332981 0
Treatment: Drugs
Description of the comparator or control
Phase 1 will be replicated identically in 8 healthy adults. However, during the second visit, participants will orally ingest a placebo supplement (90 min pre-exercise) and gel containing only 25 grams of carbohydrates (45 min pre-exercise) before undertaking the same INSCYD lactate test. Physiological responses, subjective effort ratings, tolerability and protocol adherence will be assessed using the same aforementioned measures.
Control group
Placebo

Outcomes
Primary outcome [1] 344179 0
Exercise tolerance
Timepoint [1] 344179 0
Baseline (pre-intervention), each stage of the INSCYD protocol and post-exercise. Post-intervention (single acute dose; assessed during the exercise test conducted ~90 minutes after hydrogel ingestion) Following each stage of the INSCYD lactate protocol.
Primary outcome [2] 344271 0
Supplement safety
Timepoint [2] 344271 0
Immediately post-exercise and 72 h post session.
Secondary outcome [1] 456943 0
Acid–base balance and buffering capacity (assessed as a composite outcome).
Timepoint [1] 456943 0
Baseline (pre-ingestion) Pre-exercise Immediately post-exercise
Secondary outcome [2] 456944 0
Lactate kinetics and metabolic profile (assessed as a composite outcome)
Timepoint [2] 456944 0
During exercise testing (submaximal stages and maximal effort) Recovery period post-exercise
Secondary outcome [3] 456945 0
Supplement tolerability
Timepoint [3] 456945 0
Post-exercise (same visit) 72-hour follow-up
Secondary outcome [4] 456946 0
Perceived exertion during exercise
Timepoint [4] 456946 0
At the end of each exercise stage At exercise termination

Eligibility
Key inclusion criteria
Participants must meet all of the following criteria:
1. Aged over 18 to under 65 years.
2. Body mass index (BMI) between 18–30 kg/m².
3. Recreationally active, defined as participating in structured physical activity at least twice per week.
4. Able and willing to provide written informed consent.
5. Able to attend all scheduled study visits and comply with study procedures.
Minimum age
18 Years
Maximum age
64 Years
Sex
Both males and females
Healthy volunteers
Yes
Key exclusion criteria
1. Cardiovascular risk/conditions: known coronary artery disease, heart failure, clinically significant valvular disease, uncontrolled or labile hypertension, history of syncope/arrhythmia or clinically significant palpitations, or any ACSM
contraindication to maximal/submaximal exercise testing.
2. Respiratory disease that limits safe exercise testing (e.g., unstable asthma, COPD exacerbation).
3. Renal impairment or history of clinically significant electrolyte disorders; known predisposition to alkalosis.
4. Gastrointestinal disease likely to worsen with oral supplements (e.g., active peptic ulcer disease, inflammatory bowel disease flare, severe GERD), prior or existing severe (Grade =3) treatment-related GI toxicity, or prior GI surgery that materially affects absorption.
5. Metabolic/endocrine disorders that increase risk with bicarbonate/caffeine or confound outcomes (e.g., uncompensated thyroid disease, untreated metabolic acidosis/alkalosis).
6. Diabetes requiring medication or unstable glycaemic control (risk of adverse glycaemic responses to carbohydrate/caffeine).
7. Bleeding risk: coagulopathy or use of anticoagulants/antiplatelets at doses that meaningfully increase bleeding risk from venipuncture/capillary sampling.
8. Neurological or psychiatric conditions that would preclude consent, protocol adherence, or safe exercise (e.g. uncontrolled anxiety/panic disorder relevant to caffeine ingestion).
9. Allergy/intolerance to any study product or excipient (sodium bicarbonate, caffeine, maltodextrin/fructose, hydrogel components).
10. Medication/supplement conflicts: current use of agents that materially affect acid–base balance or lactate kinetics (e.g., acetazolamide), or other performance-enhancing supplements within washout periods (see below).
11. Substance use likely to interfere with safety or data integrity (investigator judgement).
12. Pregnancy or lactation (self-report and/or testing as per institutional policy).
13. Acute illness/infection within 14 days (e.g., febrile illness) or any condition that, in the opinion of the investigator, makes participation unsafe.
14. Inability to safely complete cycling ergometer testing (e.g., limiting musculoskeletal injury).
15. Participation in another interventional trial within 30 days or concurrent participation that could confound outcomes.

Standard washouts ):
1. Beta-alanine use within the past 6 months.
2. Other ergogenic aids (e.g., nitrate/beetroot, high-dose sodium bicarbonate outside the study, creatine loading) within 4 weeks unless otherwise approved by the PI.
3. Caffeine on the day of testing outside the protocol (participants must abstain per pre-test instructions).

Study design
Purpose of the study
Treatment
Allocation to intervention
Randomised controlled trial
Procedure for enrolling a subject and allocating the treatment (allocation concealment procedures)
Allocation involved contacting the holder of the allocation schedule who was offsite.
Methods used to generate the sequence in which subjects will be randomised (sequence generation)
Simple block randomisation
Masking / blinding
Blinded (masking used)
Who is / are masked / blinded?
The people receiving the treatment/s

The people assessing the outcomes
The people analysing the results/data
Intervention assignment
Parallel
Other design features
Phase
Phase 1 / Phase 2
Type of endpoint/s
Safety/efficacy
Statistical methods / analysis
Physiological and performance outcomes: Repeated-measures ANOVA to assess time (pre- vs post-intervention) and group (intervention vs control) effects.

Within-group changes: Paired t-tests for pre/post comparisons in venous blood analysis, lactate kinetics, and INSCYD performance metrics.

Tolerability outcomes: Descriptive statistics and chi-square tests for frequency/severity of GI symptoms and palatability ratings.

Questionnaire data: Scored according to FACIT-F and EORTC QLQ-C30 guidelines; analysed for mean changes and effect sizes.

Both intention-to-treat and per-protocol analyses will be performed, with effect sizes and 95% confidence intervals reported.

Recruitment
Recruitment status
Not yet recruiting
Date of first participant enrolment
Anticipated
9/03/2026
Actual
Date of last participant enrolment
Anticipated
1/07/2027
Actual
Date of last data collection
Anticipated
1/07/2027
Actual
Sample size
Target
16
Accrual to date
Final
Recruitment in Australia
Recruitment state(s)
SA

Funding & Sponsors
Funding source category [1] 320921 0
University
Name [1] 320921 0
Flinders University
Country [1] 320921 0
Australia
Primary sponsor type
University
Name
Flinders University
Address
Country
Australia
Secondary sponsor category [1] 323620 0
None
Name [1] 323620 0
Address [1] 323620 0
Country [1] 323620 0
Other collaborator category [1] 283813 0
Commercial sector/Industry
Name [1] 283813 0
Maurten AB
Address [1] 283813 0
Country [1] 283813 0
Sweden

Ethics approval
Ethics application status
Approved
Ethics committee name [1] 319461 0
Flinders University Human Research Ethics Committee
Ethics committee address [1] 319461 0
Ethics committee country [1] 319461 0
Australia
Date submitted for ethics approval [1] 319461 0
11/08/2025
Approval date [1] 319461 0
23/10/2025
Ethics approval number [1] 319461 0

Summary
Brief summary
Trial website
Trial related presentations / publications
Public notes

Contacts
Principal investigator
Name 147394 0
Prof Andrew Rowland
Address 147394 0
Flinders University Health and Medical Research Building, Bedford Park, SA, 5042.
Country 147394 0
Australia
Phone 147394 0
+61 8 8432 4375
Fax 147394 0
Email 147394 0
[email protected]
Contact person for public queries
Name 147395 0
Andrew Rowland
Address 147395 0
Flinders University Health and Medical Research Building, Bedford Park, SA, 5042.
Country 147395 0
Australia
Phone 147395 0
+61 8 8432 4375
Fax 147395 0
Email 147395 0
[email protected]
Contact person for scientific queries
Name 147396 0
Andrew Rowland
Address 147396 0
Flinders University Health and Medical Research Building, Bedford Park, SA, 5042.
Country 147396 0
Australia
Phone 147396 0
+61 8 8432 4375
Fax 147396 0
Email 147396 0
[email protected]

Data sharing statement
Will the study consider sharing individual participant data?
Yes
Will there be any conditions when requesting access to individual participant data?
Persons/groups eligible to request access:
• Researchers
Conditions for requesting access:
• Yes, conditions apply:
• Requires a scientifically sound proposal or protocol
• Requires approval by an ethics committee
• Requires a data sharing agreement between data requester and trial custodian or sponsor
What individual participant data might be shared?
• All de-identified individual participant data
What types of analyses could be done with individual participant data?
• Any type of analysis (i.e. no restrictions on data re-use)
• Systematic reviews and meta-analyses
• Studies exploring new research questions
• Health economic analyses
• Studies testing whether findings can be repeated or confirmed
• Teaching research methods or developing new statistical techniques
When can requests for individual participant data be made (start and end dates)?
From:
After publication of main results
To:
A finite period of: 5 years
Where can requests to access individual participant data be made, or data be obtained directly?
• Email of trial custodian, sponsor or committee: [email protected]

Are there extra considerations when requesting access to individual participant data?
No


What supporting documents are/will be available?

No Supporting Document Provided


Results publications and other study-related documents

Documents added manually
No documents have been uploaded by study researchers.

Documents added automatically
No additional documents have been identified.