Tryptophan (Trp for short) is one of the 20 amino acids commonly found in proteins and belongs to the group of indispensable (essential) amino acids – the body cannot make it itself and has to take it in from food. In the world of sports nutrition it is credited with effects such as increasing growth hormone release, supporting sleep, reducing the perception of pain and increasing performance. But how much of that is true?
Metabolism and role in the body
Tryptophan is involved in several important processes in the body:
Effects on physical performance vs. the scientific reality
The main hypothesis crediting tryptophan with a positive effect on physical performance is built on the idea that, as a precursor of serotonin, it may delay the perception of pain and so improve performance.
The results suggested that tryptophan may reduce the rating of perceived exertion (RPE) and improve endurance by 49 %. These figures were later criticised as unrealistic.
L-tryptophan as sleep support
While the evidence for increasing performance is missing, tryptophan has a proven benefit in another area. L-tryptophan may be an effective food supplement for supporting sleep (Langan-Evans et al., 2023).
Conclusion for athletes
Tryptophan is an indispensable component of the diet with a profound influence on brain chemistry. The current scientific evidence does not support supplementing with it as a means of directly increasing sports performance. Its main benefit remains in the area of regulating sleep and mood outside physical activity itself.
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