- There are reports that L-tyrosine may enhance cognitive performance in situations involving stress.
- The evidence score is 7, and reliability is very limited.
- This information is aimed at those interested in short-term periods of stress or situations that require high concentration.
L-tyrosine is a type of amino acid.
This substance is generally treated as one of the amino acids taken as a supplement/dietary component.
It has been suggested that, in situations involving stress, L-tyrosine may enhance cognitive performance.
This study is based on a review (a research method that organizes existing papers and summarizes common trends) that gathered and analyzed the results of various past studies. It is not something that directly observed specific individuals to find new facts, but rather something that organizes and presents past findings.
Technically, this research takes the form of a review (a method that comprehensively surveys past research), and its reliability is considered very limited (a state in which solid evidence is still lacking). For this reason, it is difficult to judge the effect based on this report alone.
It is stated that L-tyrosine may support performance in situations involving stress or situations that require the mind to work at full capacity.
Looking at the research in more detail, it particularly touches on effects "during short-term stress" and in "situations of high cognitive demand." Here, a situation of high cognitive demand refers to a situation requiring the mind to work at full capacity (tasks requiring complex thinking or concentration).
Technically, the effect on cognitive performance under stress (efficiency in how the mind is used, such as thinking ability and concentration) is being examined. This includes not only clinical populations facing some kind of condition (groups of people judged to be in a specific state, such as in a medical setting) but also cases involving healthy individuals.
Based on the current data, the evidence score is 7, but reliability is very limited.
The evidence score is a numerical representation of how certain the information is. This figure of "7" shows that there is some basis for the finding, but its reliability is considered "very limited." This is because the supporting research is only a single review, meaning there is still little material with which to judge the certainty of the information.
Technically, the basis here is a study titled "Effect of tyrosine supplementation on clinical and healthy populations under stress or cognitive demands--A review." This study pulls together individual data from randomized controlled trials (a reliable research method in which participants are randomly divided into groups to compare effects between them), but there is not enough information to draw a conclusion from this alone.
From the current research alone, details such as who should use it and at what amount are not known.
Because this study is a review (a summary that organizes) that pulls together multiple past studies, specific conditions such as the number of participants in individual experiments, or the duration and amount taken, cannot be read from this data alone.
Technically, one reason the certainty of this information is "very limited" is the nature of the research itself. This is still a stage where much more research is needed, and it does not necessarily act the same way for everyone. Some people will not experience an effect, and it may not suit some people.
| Study | Design | Number of participants | Duration | Main result |
|---|---|---|---|---|
| Journal of Psychiatric Research (2015, PMID:26424423) | Other study design | Unknown | Unknown | A positive effect was reported |
The study subjects are clinical populations and healthy populations in situations involving stress or cognitive demand.
This means that this research is aimed at people placed in situations involving stress or cognitive load.
This content is based on a review drawing on a single study.
The study design is a format other than a randomized controlled trial (RCT).
The reliability of the reported content is considered very limited.
What effect does L-tyrosine have on stress?
There are research reports of a positive effect on stress. However, the reliability of this is very limited.
Is L-tyrosine also related to cognitive performance?
There are reports that, under short-term stress or in situations of cognitive demand, L-tyrosine may enhance cognitive performance.
What populations have been studied for L-tyrosine?
Research has been reported involving clinical populations and healthy populations in situations of stress or cognitive demand.
There are reports that L-tyrosine may help support performance in situations involving stress. However, the basis for this is a single review, and reliability is very limited. Since actual circumstances vary from person to person, why not start by reflecting on your own state with a self-check?