Can caffeine boost strength? trial tests two doses in women
NCT ID NCT07830459
First seen Sep 21, 2026 · Last updated Sep 21, 2026
Summary
Researchers compare how a single dose and a 7-day course of caffeine affect strength and power in women who already consume caffeine daily. Thirty-six resistance-trained women receive 3 mg/kg caffeine, 6 mg/kg caffeine, or a placebo in a double-blind crossover design. The study measures peak power during bench press, strength endurance, vertical jump, and medicine ball throw to see whether dose or timing changes performance.
What this could mean
Our plain-language read of the trial. This is informational only, not medical advice or a prediction.
- Active substance
- caffeine powder in capsules
- What this could lead to
- If caffeine helps, the results could inform personalized caffeine guidelines for women who lift, based on dose and timing. It could also clarify whether daily caffeine use changes how the body responds.
- What could go wrong
- This is a small, short study of 36 women who already consume caffeine daily, so results may not apply to other people or doses. Caffeine can cause jitteriness, sleep problems, or stomach upset, and performance effects may be too small to matter.
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Study facts
What this study's own registry entry says, in plain language.
- Phase
-
Not a phased trial
Phase numbers describe drug development. The registry uses this when they do not apply, as it does for trials of devices, procedures or behaviour changes, and for observational studies.
- Participants
-
36 people
The number who actually took part.
- Started
-
Feb 2023
- Finished
-
Mar 2023
- Lead sponsor
-
Other sponsor
The registry's catch-all category, for sponsors it does not file as a company, a government agency, or a research network.
Who can take part
This study's own entry requirements. Only the study team can say for certain whether you qualify.
- Ages
-
20 to 30 years
- Sex
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Female participants only
- Healthy volunteers
-
Accepted
You do not need to have the condition being studied to take part.
Show the full entry requirements Hide the full entry requirements
Copied word for word from the study's registry entry, so the wording is the study team's rather than ours.
Inclusion Criteria: 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) - Exclusion Criteria: Occurrence of any injury during the study Failure to adhere to the supplement consumption protocol Withdrawal from the study-
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As listed by the trial registrant
The condition terms exactly as the trial's registrant entered them.
Contacts and locations
Locations
-
Faculty of Sport Sciences, University of Birjand
Birjand, South Khorasan Province, 9717434765, Iran
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