CaffeineNCT07830459
Caffeine Dose and Duration in Habitual Female Users
A study testing Caffeine 3 mg/kg and Caffeine 6 mg/kg in people with Caffeine and Athletic Performance, run by Birjand University of Medical Sciences at 1 site in Iran.
Trial summary
This study compares the effects of acute (single-session) and short-term (7-day) consumption of different doses of caffeine (3 and 6 mg/kg) on maximal strength, strength endurance, vertical jump, and medicine ball throw performance in habitual caffeine-consuming women (daily intake of 5 mg/kg). Read more about this study
- Who is it for?
- Ages 20 to 30 years, women onlyHealthy volunteers can take part
- Conditions the study is for
- Caffeine, Athletic Performance, Resistance Traaining
- What is being tested?
- Caffeine 3 mg/kg and Caffeine 6 mg/kg
- Type of treatment
- Pill or oral medicine
- Could I receive a placebo?
- Yes, some participants may receive a placebo
- How many people
- 36 participants
- Where
- 1 siteIran
- Study dates
- 12 Feb 2023to 30 Mar 2023
- 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 20 to 30 years
- Women only
- Healthy volunteers accepted
- Adult
Who may be able to join
- Absence of neuromuscular and musculoskeletal disorders
- At least 2 years of regular resistance training experience (minimum 3 sessions per week)
- At least 6 months of resistance training prior to enrollment
- Absence of renal and hepatic disorders
- Daily caffeine consumption of 5 mg/kg body weight (based on questionnaire)
- No use of specific medications or supplements that could affect study outcomes (e.g., beta-alanine, creatine, pre-workout supplements) -
Who cannot join
- Occurrence of any injury during the study
- Failure to adhere to the supplement consumption protocol
- Withdrawal from the study-
Trial locations and contacts
1 site in 1 country.
Iran1 site
Faculty of Sport Sciences, University of Birjand
Birjand, South Khorasan Province, 9717434765
About this study
Official title: Comparison Effects of Acute and Short-Term Consumption of Different Doses of Caffeine on Strength and Power Indices in Habitual Caffeine-Consuming Women
This study compares the effects of acute (single-session) and short-term (7-day) consumption of different doses of caffeine (3 and 6 mg/kg) on maximal strength, strength endurance, vertical jump, and medicine ball throw performance in habitual caffeine-consuming women (daily intake of 5 mg/kg). Thirty-six resistance-trained women were randomly assigned to three groups: 3 mg/kg caffeine, 6 mg/kg caffeine, or placebo in a double-blind crossover design. Participants completed both acute (60 min pre-exercise) and short-term (7 consecutive days) protocols. The main findings showed that acute ingestion of 6 mg/kg caffeine impaired peak power in the maximal strength test, while short-term consumption of the same dose improved peak power in the strength-endurance test. The 3 mg/kg dose was ineffective in all conditions. Caffeine did not affect jump or throw performance. The study highlights the need for individualized caffeine guidelines based on timing, dosage, and habituation status.
- Conditions
- Caffeine, Athletic Performance, Resistance Traaining
- Being tested
- Caffeine 3 mg/kg, Caffeine 6 mg/kg, Placebo
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Caffeine 3 mg/kgDietary supplement
Caffeine powder (99% purity) encapsulated in gelatin capsules at a dose of 3 mg per kilogram of body weight. The capsules are identical in appearance, odor, and taste to the placebo. Participants consume the capsules daily for 7 consecutive days. On the testing day, the capsules are ingested 60 minutes prior to the exercise tests.
Caffeine 6 mg/kgDietary supplement
Caffeine powder (99% purity) encapsulated in gelatin capsules at a dose of 6 mg per kilogram of body weight. The capsules are identical in appearance, odor, and taste to the placebo. Participants consume the capsules daily for 7 consecutive days. On the testing day, the capsules are ingested 60 minutes prior to the exercise tests.
PlaceboDietary supplement
Placebo capsules containing inert flour (or microcrystalline cellulose), identical in appearance, odor, and taste to the caffeine capsules. Participants consume the capsules daily for 7 consecutive days. On the testing day, the capsules are ingested 60 minutes prior to the exercise tests.
| Study group | Role | What they receive |
|---|---|---|
| Caffeine 3 mg/kg | Experimental | Participants received 3 mg/kg body weight of caffeine powder in gelatin capsules daily for 7 days. Acute consumption: 60 minutes before testing. Short-term consumption: 7 consecutive days Receives: Dietary Supplement: Caffeine 3 mg/kg |
| Caffeine 6 mg/kg | Experimental | Participants received 6 mg/kg body weight of caffeine powder in gelatin capsules daily for 7 days. Acute consumption: 60 minutes before testing. Short-term consumption: 7 consecutive days Receives: Dietary Supplement: Caffeine 6 mg/kg |
| Placebo | Placebo comparator | Participants received identical capsules containing flour, consumed daily for 7 days Receives: Dietary Supplement: Placebo |
What is being measured
The primary outcome is the main question the study is designed to answer.
Change in Peak Power (PP) During Maximal Strength Test
Peak concentric power (Watts) during 1-RM bench press test, measured using a validated Kinect camera
Measured: Baseline, 60 minutes post-ingestion (acute), and after 7 days of supplementation (short-term)
Secondary outcomes (4)
Change in Peak Power During Strength-Endurance Test
eak concentric power (Watts) during bench press at 50% of 1-RM to failure, measured using Kinect camera
Measured: Baseline, 60 minutes post-ingestion (acute), and after 7 days of supplementation (short-term)
Change in Medicine Ball Throw Distance
Distance (cm) of 3-kg medicine ball throw from chest position
Measured: Baseline, 60 minutes post-ingestion (acute), and after 7 days of supplementation (short-term)
Change in Vertical Jump Height
Countermovement jump height (cm) measured using Kinect camera
Measured: Baseline, 60 minutes post-ingestion (acute), and after 7 days of supplementation (short-term)
Change in Number of Repetitions (Strength-Endurance)
Number of repetitions performed at 50% of 1-RM until failure
Measured: Baseline, 60 minutes post-ingestion (acute), and after 7 days of supplementation (short-term)
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted21 Sep 2026
- Study start12 Feb 2023
- Primary completion20 Mar 2023
- Study completion30 Mar 2023
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for CaffeineStudies 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
- Parallel groups
- Masking
- Double blind
- Who is masked
- Participant, Investigator
- Enrolment
- 36 participants (actual)
Sponsor and investigators
- Lead sponsor
- Birjand University of Medical Sciences
- Sponsor type
- University, hospital or other
- Responsible party
- Principal investigator, Mohsen mohammadnia ahmadi, Birjand University of Medical Sciences
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07830459
- Sponsor's protocol ID
- IR.BIRJAND.REC.1401.012
- Status last verified
- Sep 2026
- First submitted
- 15 Sep 2026
- Last updated
- 21 Sep 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 21 Sep 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Comparison Effects of Acute and Short-Term Consumption of Different Doses of Caffeine on Strength and Power Indices in Habitual Caffeine-Consuming Women
- ClinicalTrials.gov ID
- NCT07830459
- Acronym / sponsor ID
- IR.BIRJAND.REC.1401.012
- Conditions
- Caffeine, Athletic Performance, Resistance Traaining
- Study type
- Interventional
- Recruitment status
- Completed
- Enrolment
- 36 participants (actual)
- Lead sponsor
- Birjand University of Medical SciencesUniversity, hospital or other
- Study start
- 12 Feb 2023 (actual)
- Primary completion
- 20 Mar 2023 (actual)
- Study completion
- 30 Mar 2023 (actual)
- First posted
- 21 Sep 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 study compares the effects of acute (single-session) and short-term (7-day) consumption of different doses of caffeine (3 and 6 mg/kg) on maximal strength, strength endurance, vertical jump, and medicine ball throw performance in habitual caffeine-consuming women (daily intake of 5 mg/kg). Thirty-six resistance-trained women were randomly assigned to three groups: 3 mg/kg caffeine, 6 mg/kg caffeine, or placebo in a double-blind crossover design. Participants completed both acute (60 min pre-exercise) and short-term (7 consecutive days) protocols. The main findings showed that acute ingestion of 6 mg/kg caffeine impaired peak power in the maximal strength test, while short-term consumption of the same dose improved peak power in the strength-endurance test. The 3 mg/kg dose was ineffective in all conditions. Caffeine did not affect jump or throw performance. The study highlights the need for individualized caffeine guidelines based on timing, dosage, and habituation status.
Study design
- Primary purpose
- Basic science
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Double blind (participant, investigator)
- Number of arms
- 3
| Arm | Type | Receives |
|---|---|---|
| Caffeine 3 mg/kg | Experimental | Dietary Supplement: Caffeine 3 mg/kgParticipants received 3 mg/kg body weight of caffeine powder in gelatin capsules daily for 7 days. Acute consumption: 60 minutes before testing. Short-term consumption: 7 consecutive days |
| Caffeine 6 mg/kg | Experimental | Dietary Supplement: Caffeine 6 mg/kgParticipants received 6 mg/kg body weight of caffeine powder in gelatin capsules daily for 7 days. Acute consumption: 60 minutes before testing. Short-term consumption: 7 consecutive days |
| Placebo | Placebo comparator | Dietary Supplement: PlaceboParticipants received identical capsules containing flour, consumed daily for 7 days |
Who may qualify
- Ages
- 20 to 30 years
- Sex
- Female only
- Healthy volunteers
- Accepted
- Age groups
- Adult
Key inclusion criteria (6 listed)
- Absence of neuromuscular and musculoskeletal disorders
- At least 2 years of regular resistance training experience (minimum 3 sessions per week)
- At least 6 months of resistance training prior to enrollment
- Absence of renal and hepatic disorders
- Daily caffeine consumption of 5 mg/kg body weight (based on questionnaire)
Key exclusion criteria (3 listed)
- Occurrence of any injury during the study
- Failure to adhere to the supplement consumption protocol
- Withdrawal from the study-
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 |
|---|---|---|
| Caffeine 3 mg/kgCaffeine powder (99% purity) encapsulated in gelatin capsules at a dose of 3 mg per kilogram of body weight. The capsules are identical in appearance, odor, and taste to the placebo. Participants consume the capsules daily for 7 consecutive days. On the testing day, the capsules are ingested 60 minutes prior to the exercise tests. | Dietary supplement | Caffeine 3 mg/kg |
| Caffeine 6 mg/kgCaffeine powder (99% purity) encapsulated in gelatin capsules at a dose of 6 mg per kilogram of body weight. The capsules are identical in appearance, odor, and taste to the placebo. Participants consume the capsules daily for 7 consecutive days. On the testing day, the capsules are ingested 60 minutes prior to the exercise tests. | Dietary supplement | Caffeine 6 mg/kg |
| PlaceboPlacebo capsules containing inert flour (or microcrystalline cellulose), identical in appearance, odor, and taste to the caffeine capsules. Participants consume the capsules daily for 7 consecutive days. On the testing day, the capsules are ingested 60 minutes prior to the exercise tests. | Dietary supplement | Placebo |
Primary outcome
Change in Peak Power (PP) During Maximal Strength Test
Time frame: Baseline, 60 minutes post-ingestion (acute), and after 7 days of supplementation (short-term)
Peak concentric power (Watts) during 1-RM bench press test, measured using a validated Kinect camera
4 secondary outcomes
Change in Peak Power During Strength-Endurance Test
Time frame: Baseline, 60 minutes post-ingestion (acute), and after 7 days of supplementation (short-term)
Change in Medicine Ball Throw Distance
Time frame: Baseline, 60 minutes post-ingestion (acute), and after 7 days of supplementation (short-term)
Change in Vertical Jump Height
Time frame: Baseline, 60 minutes post-ingestion (acute), and after 7 days of supplementation (short-term)
Change in Number of Repetitions (Strength-Endurance)
Time frame: Baseline, 60 minutes post-ingestion (acute), and after 7 days of supplementation (short-term)
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 21 Sep 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.
The record lists no contact. Use the official record to reach the sponsor.
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing Caffeine 3 mg/kg and Caffeine 6 mg/kg in people with Caffeine and Athletic Performance, run by Birjand University of Medical Sciences at 1 site in Iran.
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 6 inclusion and 3 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: finished, as of the sponsor's last update on 21 Sep 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 Iran. 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?
Change in Peak Power (PP) During Maximal Strength Test (time frame: Baseline, 60 minutes post-ingestion (acute), and after 7 days of supplementation (short-term)). 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 21 Sep 2026.