L-Tryptophan is one of the essential amino acids that must be obtained through diet.  It is naturally found in red meat, poultry, eggs, and dairy.
L-tryptophan is important for many organs in the body. L-tryptophan turns into serotonin in the body, that has anti-depressant affect and controls mood.  It is also known to help with sleep. Serotonin is a hormone that transmits signals between nerve cells. Changes in serotonin levels in the brain can affect mood.  

• Appearance: White to light-yellow cyrstals or crystalline powder.
• Slightly bitter taste.
• Solubility: Soluble in water.