Tryptophan is not the cause of your sleepiness.
Tryptophan synthesizes into serotonin, then to melatonin, only then leading to sleepiness.
Tryptophan, alone, will not make you sleepy.
Carbohydrates play the most significant role in optimizing tryptophan synthesis.
Turkey without potatoes, pie, cranberry sauce, stuffing, and more pie is ineffectual.
When you identify the cause of something, you must also account for critical supporting components.
Growth and development function similarly.
If you evaluate your development in isolation, you will miss important factors.
Developing a skill in isolation is equal to identifying the cause while ignoring critical components.
Coffee with no mug is ineffectual and messy,