What Is It?
Health Benefits
Dosage Information

Guidelines for Use

General Interaction

Possible Side Effects



Evidence Based Rating Scale 

What Is It? 

The pain reliever DLPA (D,L-phenylalanine) contains two forms of the amino acid phenylalanine. The "L" form is a natural substance found in Protein-rich foods; it's believed to bolster mood-elevating chemicals in the brain, such as dopamine and norepinephrine. The "D" form of phenylalanine, on the other hand, is made synthetically in a laboratory; it appears to block a nervous system Enzyme that amplifies pain signals. In other words, it may prevent the breakdown of the brain's natural narcotics. 

DLPA supplements combine the "L" and "D" forms of phenylalanine, packing a potent one-two punch, and quickly relieving minor depression and physical discomforts. 

Health Benefits 

Research indicates that DLPA can be an effective part of an overall program to fight chronic pain and beat the blues, including the mood swings of premenstrual syndrome (PMS). Some sources contend that DLPA can increase energy and mental alertness, as well as heighten the ability to focus in individuals with attention deficit hyperactivity disorder (ADHD). 

Combined with ultraviolet (UVA) light therapy, various forms of phenylalanine have also been proposed as a treatment for vitiligo, a somewhat mysterious dermatologic condition characterized by the development of white, pigment-free patches of skin.  Patients with Parkinson's disease also have experienced some relief from symptoms when taking DLPA and doing a pain relief therapy called TENS (transcutaneous electrical nerve stimulation). However, rigorous research into these uses is still needed. 

Specifically, DLPA may help to: 

  • Ease depression. Several clinical studies have examined the effect of DLPA supplements on mood. In one trial, 12 of 20 depressed men and women who took 75 to 200 mg of DLPA a day reported being free of depression after less than three weeks of treatment, and four reported feeling somewhat better. (1) Another early trial involving 40 depressed patients showed DLPA may be as effective as the conventional medication imipramine in treating depression. (2) However, these studies were conducted more than two decade ago. Newer studies are needed to confirm or refute efficacy in treating depression.

  • Allay chronic pain. Although more research is needed, there is some evidence that DLPA can help to relieve certain types of chronic pain, including muscle aches and persistent arthritis-related pain. The supplement appears to inhibit the actions of a pain-inducing protein called enkephalinase. Some scientists speculate that DLPA also helps by boosting the effectiveness of narcotics and other pain medications. However, scientific studies have been inconclusive. In a double-blind study of 30 patients with chronic pain from various conditions that had not been relieved by several other treatments, 25% of patients reported more pain relief after taking 250 mg of DLPA four times a day for four weeks compared to the placebo group. However, 22% of patients reported more pain relief from placebo, and 53% of patients reported no difference in pain relief during the study. (3) Preliminary evidence indicates DLPA taken in conjunction with opiates for pain may increase efficacy of the conventional medications and reduce the dosage of opiates required to treat pain. (4) More research is needed to confirm or refute efficacy in treating chronic pain.

  • Enhance concentration in attention deficit-hyperactivity disorder (ADHD). Some research indicates patients with ADHD may have lower levels of amino acids such as phenylalanine. (5) Proponents suggest the ability of DLPA to enhance chemicals in the brain leads to improved concentration in patients with ADHD. However, research in this area has been disappointing. In a 1985 study of 19 adults with ADHD, 13 subjects who completed the study and were treated with DLPA for two weeks showed significant improvement in overall ratings and, specifically, in mood enhancement. However, all positive benefits of DLPA faded within three months of continued treatment. (6) And in a 1987 study of 11 hyperactive boys, no changes (improvements or deterioration) in behavior were seen in the patients treated with 20 mg of DLPA daily for two weeks and placebo for two weeks. (7) This research also is more than two decades old and requires new trials to confirm or refute efficacy.

  • Improve the appearance of vitiligo. In combination with ultraviolet light (UVA) therapy, DLPA has been shown in several studies to activate the cells responsible for pigmentation in adults and children. Thus, by activating these cells, DLPA helps to return the white, pigment-free skin of vitiligo back to its original color. Both oral and topical formulations have shown efficacy. (8) A review of studies has shown doses lower than 50 mg of oral DLPA daily plus UVA therapy improved pigmentation in as much as 70% of vitiligo spots in one open trial of 149 patients, up to 60% in a double-blind trial of 32 patients, and up to 50% in another open trial of 20 patients. (9, 10) In a study of 13 children treated with oral DLPA and UVA therapy, three children experienced re-pigmentation of all vitiliginous areas, six showed 50% to 90% improvement, and four failed to respond. (11) In a 2002 study of 70 patients treated with 100 mg of oral DLPA plus 10% L-phenylalanine topical gel and exposed to sunlight or UVA lamps for six months, more than 90% of patients showed improvement in vitiligo, with more than two-thirds of those patients achieving re-pigmentation in at least 75% of vitiliginous areas (primarily on the face). (12) A 2008 review of 15 trials evaluating natural vitiligo treatments found that all trials involving DLPA in conjunction with light therapy reported beneficial findings and that it warrants further investigation. (13)

  • Reduce symptoms of Parkinson's disease. Limited research indicates DLPA may help to improve rigidity, walking, speech and depression associated with Parkinson's disease. (14) More research is needed to determine efficacy in treating symptoms of Parkinson's disease.  

Dosage Information 

Special tips:

--Look for formulations that contain both the "D" and "L" forms of the amino acid phenylalanine. This combination is less likely to lead to high blood pressure than using the natural "L" form alone.

--If you have high blood pressure, start with very low amounts, such as 100 mg a day. Increase the dose slowly and only under a doctor's supervision.

--As is the case with most dietary supplements, DLPA has not been studied in pregnant or breast-feeding women, those with kidney or liver disease, and in only very limited fashion in children. Safety and proper dosing in these groups has not been established. 

For relief of depression: 200 mg a day, taken in the morning. 

For chronic pain: Up to 1,500 mg daily, taken on an empty stomach. 

For ADHD: 20 mg daily has been used.

For vitiligo: 50 to 100 mg oral DLPA daily along with UVA exposure, and/or a 10% phenylalanine topical cream along with UVA exposure has been used. 

For Parkinson's disease: 200 to 500 mg oral DLPA has been used. 

Guidelines for Use 

As with other amino acid supplements, it's best to take DLPA on an empty stomach with water or juice about an hour before meals. High-protein foods, in particular, can interfere with proper absorption. 

Store in a cool, dry place, such as a closet shelf away from heat, light, and moisture. (Avoid the humid bathroom medicine cabinet.) 

General Interaction 

Because DLPA exerts its effects through the central nervous system, avoid taking it with prescription antidepressants or stimulants, unless specifically instructed to do so by a doctor. 

Some research indicates that DLPA can exacerbate facial tics and other symptoms of tardive dyskinesia, a troubling movement disorder caused by long-term use of antipsychotic medicines. Stop taking DLPA and consult a doctor for concerns about reactions to DLPA. 

As with other Amino acids, DLPA may interfere with the effects of levodopa, a drug commonly used to treat Parkinson's disease. Don't combine the two. 

Note: For information on interactions with specific generic drugs, see our WholeHealthMD Drug/Nutrient Interactions Chart. 

Possible Side Effects 

At recommended doses, DLPA occasionally causes mild side effects, such as heartburn, nausea, or headaches. At excessive doses (more than 1,500 mg a day), it can cause numbness, tingling, or other signs of nerve damage. 

DLPA may have the unwanted effect of raising blood pressure, although the D, L combination form is less likely to do so than supplements containing only the "L" form of the amino acid. 


Use DLPA under the supervision of a doctor familiar with its use. When taken in high doses (greater than 1,500 mg a day) over prolonged periods of time, nerve damage may develop. Lower doses appear to be safe. 

For those with high blood pressure or who are prone to anxiety or panic attacks, DLPA could seriously aggravate the condition. Let a doctor know if signs or symptoms worsen while taking DLPA. 

Pregnant women should not take DLPA, since it has not been well studied in this group.  

For people who have been diagnosed with malignant melanoma, a potentially deadly form of skin cancer, some doctors caution against taking DLPA. There has been some concern that phenylalanine could stimulate the pigment producing cancer cells, although the connection, if any, remains unclear. 

Persons with phenylketonuria (PKU), a rare, inherited metabolic disorder should avoid taking DLPA, as they lack an enzyme that converts phenylalanine to tyrosine and must follow very strict dietary guidelines to prevent toxic damage to the nervous system. 


1. Beckmann H, Strauss MA, Ludolph E. DL-phenylalanine in depressed patients: an open study. J Neural Transm. 1977;41(2-3):123-34.
2. Beckmann H, Athen D, Olteanu M, et al. DL-phenylalanine versus imipramine: a double-blind controlled study. Arch Psychiatr Nervenkr. 1979 Jul 4;227(1):49-58.
3. Walsh NE, Ramamurthy S, Schoenfeld L, Hoffman J. Analgesic effects of D-phenylalanine in chronic pain patients. Arch Phys Med Rehabil. 1986 Jul;67(7):436-9.
4. Russell AL, McCarty MF. DL-phenylalanine markedly potentiates opiate analgesia – an example of nutrient/pharmaceutical up-regulation of the endogenous analgesia system. Med Hypotheses. 2000 Oct;55(4):283-8.
5. Bornstein RA, Baker GB, Carroll A, et al. Plasma amino acids in attention deficit disorder. Psychiatry Res. 1990;33:301-6.
6. Wood DR, Reimherr FW, Wender PH. Treatment of attention deficit disorder with DL-phenylalanine. Psychiatry Res. 1985 Sep;16(1):21-6.
7. Zametkin AJ, Karoum F, Rapoport JL. Treatment of hyperactive children with D-phenylalanine. Am J Psychiatry. 1987 Jun;144(6):792-4.
8. Thiele B, Steigleder GK. Repigmentation treatment of vitiligo with L-phenylalanine and UVA irradiation. Z Hautkr. 1987 Apr 1;62(7):519-23.
9. Antoniou C, Schulpis H, Michas T, et al. Vitiligo therapy with oral and topical phenylalanine with UVA exposure. Int J Dermatol. 1989;28:545-7.
10. Siddiqui AH, Stolk LM, Bhaggoe R, et al. L-phenylalanine and UVA irradiation in the treatment of vitiligo. Dermatology. 1994;188(3):215-8.
11. Schulpis CH, Antoniou C, Michas T. Phenylalanine plus ultraviolet light: preliminary report of a promising treatment for childhood vitiligo. Pediatr Dermatol. 1989 Dec;6(4):332-5.
12. Camacho F, Mazuecos J. Oral and topical L-phenylalanine, clobetasol propionate, and UVA/sunlight – a new study for the treatment of vitiligo. J Drugs Dermatol. 2002 Sep;1(2):127-31.
13. Szczurko O, Boon HS. A systematic review of natural health product treatment for vitiligo. BMC Dermatol. 2008 May 22;8:2.
14. Heller B, Fischer BE, Martin R. Therapeutic action of D-phenylalanine in Parkinson's disease. Arzneimittelforschung. 1976;26:577-9.

Evidence Based Rating Scale

The Evidence Based Rating Scale is a tool that helps consumers translate the findings of medical research studies and what our clinical advisors have found to be efficacious in their personal practice into a visual and easy to interpret format. This tool is meant to simplify the information on supplements and therapies that demonstrate promise in the treatment of certain conditions.








Preliminary studies indicate lack of efficacy. Doses were small and research is dated. New studies are needed to confirm or refute efficacy. (6, 7)

Chronic pain  
Preliminary evidence indicates potential efficacy to reduce pain, and to enhance efficacy of and reduce dosage of opiates when taken in conjunction. More research is needed to confirm or refute efficacy. (3, 4)
Small preliminary studies indicate potential efficacy. More research is needed to confirm or refute efficacy. (1, 2)

Parkinson's disease  
Research is limited. More research is needed. (14)

Several studies and a review indicate efficacy in improving pigmentation. (8-13)

Date Published: 04/18/2005
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