DL-Phenylalanine contains both the essential amino acid L-phenylalanine and D-phenylalanine. Studies have shown that L-phenylalanine can elevate the mood, making DLPA a useful agent in combating depression. DLPA can also be used to treat chronic pain since it boosts the body's natural pain-killing response.


What it is

Phenylalanine occurs in two chemical forms: L-phenylalanine, a natural amino acid found in proteins; and its mirror image, D-phenylalanine, a form synthesized in a laboratory. Some research has involved the L-form, others the D-form, and still others a combination of the two known as DL-phenylalanine.


What it does

In the body, phenylalanine is converted into another amino acid called tyrosine. Tyrosine in turn is converted into L-dopa, norepinephrine, and epinephrine, three key neurotransmitters (chemicals that transmit signals between nerve cells). Because some antidepressants work by raising levels of norepinephrine, various forms of phenylalanine have been tried as a possible treatment for depression.

D-phenylalanine (but not L-phenylalanine) has been proposed to treat chronic pain. It blocks enkephalinase, an enzyme that may act to increase pain levels in the body.



  • Depression
  • Pain reliever
  • Vitiligo
  • Multiple sclerosis
  • Parkinson's disease



D- and DL-phenylalanine are typically taken at a dose of 100 to 200 mg daily for the treatment of depression. For the treatment of chronic pain, studies have used D-phenylalanine in doses as high as 2,500 mg daily.