Cognitive FunctionPhase 4NCT00981955
The Effects of Caffeine and L-theanine Both Alone and in Combination on Cerebral Blood Flow, Cognition and Mood
A Phase 4 study testing Caffeine and L-theanine in people with Cognitive Function and Mood, run by Northumbria University at 1 site in United Kingdom.
Trial summary
Although the beneficial effects of caffeine on cognition and mood have been reported in a number of studies, relatively few studies have looked at the effects of caffeine in combination with other phytonutrients despite the fact that caffeine is seldom consumed in isolation. Read more about this study
- Who is it for?
- Ages 18 to 35 yearsHealthy volunteers can take part
- Conditions the study is for
- Cognitive Function, Mood
- What is being tested?
- Caffeine and L-theanine
- Type of treatment
- Pill or oral medicine
- Could I receive a placebo?
- Yes, some participants may receive a placebo
- How many people
- 24 participants
- Where
- 1 siteUnited Kingdom
- Study dates
- Aug 2009to Feb 2010
- Phase
- Phase 4
- 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 35 years
- All sexes
- Healthy volunteers accepted
- Adult
Who may be able to join
- Healthy
- Aged 18-35
- Either caffeine consumers (consume more than 150mg caffeine per day) or non-consumers (less than 44mg caffeine per day).
Who cannot join
- Smoke or consume any tobacco products
- Not proficient in English language
- Pregnant (or seeking to become pregnant)
- Taking recreational, over the counter/prescription medication (including the contraceptive pill), and/or dietary/herbal supplements
- Have food allergies or sensitivities
- Have history of/current head trauma, learning difficulties , ADHD, migraines or any gastric problems
Trial locations and contacts
1 site in 1 country.
United Kingdom1 site
Northumbria University
Newcastle upon Tyne, Tyne & Wear, Ne1 8ST
About this study
Official title: A Randomised, Double Blind, Placebo-controlled Study to Evaluate the Effects of Caffeine and L-theanine Both Alone and in Combination on Cerebral Blood Flow, Cognition and Mood.
Although the beneficial effects of caffeine on cognition and mood have been reported in a number of studies, relatively few studies have looked at the effects of caffeine in combination with other phytonutrients despite the fact that caffeine is seldom consumed in isolation. L-theanine is a naturally occurring amino-acid found in tea, and has been used historically as a relaxing agent (Haskell et al., 2008). Few have assessed the impact of l-theanine on cognition, but of those that have, the most interesting results were obtained when l-theanine was assessed in combination with caffeine (Haskell et al., 2008). It remains unclear what is underlying the reported effects.
Near Infrared Spectroscopy (NIRS) is an emerging neuroimaging technology that is capable of determining changes in cerebral blood flow (CBF) by measuring the optical properties of oxygenated and deoxygenated blood (Bunce et al., 2006). No study to date has used NIRS to assess cerebral blood flow following treatment with either caffeine, l-theanine or a combination of both. It is anticipated that the proposed study will provide some insight into the mechanism of the previously observed effects both alone and in combination.
A randomised, double-blind, placebo controlled, balanced crossover design study will assess the effects of 75mg caffeine, 50mg l-theanine and a 75mg caffeine/50mg l-theanine combination in 24 young healthy adults (18-35). Cognitive and mood assessments will take place at baseline and at 30 minutes following treatment whilst cerebral haemodynamics are measured via the technique of NIRS.
- Conditions
- Cognitive Function, Mood
- Being tested
- Caffeine and L-theanine
- Keywords
- Caffeine, Ltheanine, Near Infrared Spectroscopy, Cerebral Blood Flow, Cognitive Function, Mood
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Caffeine and L-theanineDietary supplement
Also called Sun-theanine (l-theanine)
Acute oral administration of 75mg of caffeine, 50mg l-theanine, 75mg caffeine and 50mg l-theanine in combination or placebo. One dosage administered on each of four separate study days.
| Study group | Role | What they receive |
|---|---|---|
| 75mg caffeine | Active comparator | Not described Receives: Dietary Supplement: Caffeine and L-theanine |
| 50mg l-theanine | Active comparator | Not described Receives: Dietary Supplement: Caffeine and L-theanine |
| 75mg caffeine and 50mg l-theanine | Active comparator | Not described Receives: Dietary Supplement: Caffeine and L-theanine |
| 0mg caffeine/l-theanine | Placebo comparator | Not described Receives: Dietary Supplement: Caffeine and L-theanine |
What is being measured
The primary outcome is the main question the study is designed to answer.
Cerebral blood flow
Measured: 0-80 minutes post dose
Cognitive function
Measured: 0-70 minutes post-dose
Mood
Measured: 85 minutes post dose
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted22 Sep 2009 (estimated)
- Study startAug 2009
- Primary completionFeb 2010
- Study completionFeb 2010
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Cognitive FunctionStudies 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 4
- Primary purpose
- Basic science
- Allocation
- Randomised
- Intervention model
- Crossover
- Masking
- Triple blind
- Who is masked
- Participant, Investigator, Outcomes assessor
- Enrolment
- 24 participants (actual)
Sponsor and investigators
- Lead sponsor
- Northumbria University
- Sponsor type
- University, hospital or other
- Investigators
- Crystal Haskell, PhD, Principal investigator, Northumbria University
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT00981955
- Sponsor's protocol ID
- 25AA1
- Status last verified
- Jul 2010
- First submitted
- 21 Sep 2009
- Last updated
- 23 Jul 2010
- Results posted
- No
- Data monitoring committee
- No
Study at a glance
From the registry record, last updated by the sponsor on 23 Jul 2010. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- A Randomised, Double Blind, Placebo-controlled Study to Evaluate the Effects of Caffeine and L-theanine Both Alone and in Combination on Cerebral Blood Flow, Cognition and Mood.
- ClinicalTrials.gov ID
- NCT00981955
- Acronym / sponsor ID
- 25AA1
- Conditions
- Cognitive Function, Mood
- Keywords
- Caffeine, Ltheanine, Near Infrared Spectroscopy, Cerebral Blood Flow, Cognitive Function, Mood
- Phase
- Phase 4
- Study type
- Interventional
- Recruitment status
- Completed
- Enrolment
- 24 participants (actual)
- Lead sponsor
- Northumbria UniversityUniversity, hospital or other
- Study start
- Aug 2009
- Primary completion
- Feb 2010 (actual)
- Study completion
- Feb 2010 (actual)
- First posted
- 22 Sep 2009 (estimated)
- 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.
Although the beneficial effects of caffeine on cognition and mood have been reported in a number of studies, relatively few studies have looked at the effects of caffeine in combination with other phytonutrients despite the fact that caffeine is seldom consumed in isolation. L-theanine is a naturally occurring amino-acid found in tea, and has been used historically as a relaxing agent (Haskell et al., 2008). Few have assessed the impact of l-theanine on cognition, but of those that have, the most interesting results were obtained when l-theanine was assessed in combination with caffeine (Haskell et al., 2008). It remains unclear what is underlying the reported effects.
Near Infrared Spectroscopy (NIRS) is an emerging neuroimaging technology that is capable of determining changes in cerebral blood flow (CBF) by measuring the optical properties of oxygenated and deoxygenated blood (Bunce et al., 2006). No study to date has used NIRS to assess cerebral blood flow following treatment with either caffeine, l-theanine or a combination of both. It is anticipated that the proposed study will provide some insight into the mechanism of the previously observed effects both alone and in combination.
A randomised, double-blind, placebo controlled, balanced crossover design study will assess the effects of 75mg caffeine, 50mg l-theanine and a 75mg caffeine/50mg l-theanine combination in 24 young healthy adults (18-35). Cognitive and mood assessments will take place at baseline and at 30 minutes following treatment whilst cerebral haemodynamics are measured via the technique of NIRS.
Study design
- Primary purpose
- Basic science
- Allocation
- Randomised
- Intervention model
- Crossover
- Masking
- Triple blind (participant, investigator, outcomes assessor)
- Number of arms
- 4
| Arm | Type | Receives |
|---|---|---|
| 75mg caffeine | Active comparator | Dietary Supplement: Caffeine and L-theanine |
| 50mg l-theanine | Active comparator | Dietary Supplement: Caffeine and L-theanine |
| 75mg caffeine and 50mg l-theanine | Active comparator | Dietary Supplement: Caffeine and L-theanine |
| 0mg caffeine/l-theanine | Placebo comparator | Dietary Supplement: Caffeine and L-theanine |
Who may qualify
- Ages
- 18 to 35 years
- Sex
- All
- Healthy volunteers
- Accepted
- Age groups
- Adult
Key inclusion criteria (3 listed)
- Healthy
- Aged 18-35
- Either caffeine consumers (consume more than 150mg caffeine per day) or non-consumers (less than 44mg caffeine per day).
Key exclusion criteria (6 listed)
- Smoke or consume any tobacco products
- Not proficient in English language
- Pregnant (or seeking to become pregnant)
- Taking recreational, over the counter/prescription medication (including the contraceptive pill), and/or dietary/herbal supplements
- Have food allergies or sensitivities
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 and L-theanineAlso: Sun-theanine (l-theanine)Acute oral administration of 75mg of caffeine, 50mg l-theanine, 75mg caffeine and 50mg l-theanine in combination or placebo. One dosage administered on each of four separate study days. | Dietary supplement | 0mg caffeine/l-theanine, 50mg l-theanine, 75mg caffeine, 75mg caffeine and 50mg l-theanine |
Primary outcome
Cerebral blood flow
Time frame: 0-80 minutes post dose
Cognitive function
Time frame: 0-70 minutes post-dose
Mood
Time frame: 85 minutes post dose
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 23 Jul 2010.
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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.
Crystal Haskell, PhD principal investigator
Northumbria University
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A Phase 4 study testing Caffeine and L-theanine in people with Cognitive Function and Mood, run by Northumbria University at 1 site in United Kingdom.
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 3 inclusion and 6 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 23 Jul 2010. 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 Kingdom. 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.
What does this phase mean?
Phase 4 studies take place after a treatment is approved, to learn more about its long-term benefits and risks in everyday use.
Not every study follows the same path, and some studies (observational studies, device studies) have no phase.
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?
Cerebral blood flow (time frame: 0-80 minutes post dose). 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 23 Jul 2010.