Phenylalanine is an amino acid.  There are three forms: L-, D-, and DL- phenylalanine.  L-phenylalanine is found naturally in foods such as meat and eggs.
People use phenylalanine for a disorder that causes white patches to develop on the skin (vitiligo).  It is also used for attention-deficit hyperactivity disorder (ADHD), chronic pain, aging skin, depression.

• Appearance: White to off-white crystals or crystalline powder.
• Solubility: Soluble in water.
• Stability: Stable. Incompatible with strong oxidizing agents.