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DLPA (DL-phenylalanine) Benefits, Side Effects & Dosage

Written by Aleksa Ristic, MS (Pharmacy) | Last updated:
Puya Yazdi
Medically reviewed by
Puya Yazdi, MD | Written by Aleksa Ristic, MS (Pharmacy) | Last updated:

Flip and mix molecules of phenylalanine, and you’ll get DPLA: an amino acid mixture with surprising features. Users claim it can help overcome depression, chronic pain, and attention disorders. But is this true? Read on for an evidence-based review of DLPA benefits and side effects.

What is DLPA?


DLPA (DL-phenylalanine) is a nutritional supplement with 2 different forms of phenylalanine in equal amounts: D- and L-phenylalanine. As you can see in the image above, they are “mirror images” of the same amino acid oriented differently in space [1].

L-phenylalanine is the active form in the human body; it builds proteins, neurotransmitters, and other crucial molecules. It’s an essential amino acid, which means we need to get it from foods such as eggs, meat, soy, nuts, and dairy [2, 3].

D-phenylalanine is the synthetic form made in the lab. Although our bodies can’t use it as a building block, it produces specific health effects [4, 5].

People take DLPA to boost energy, manage pain, balance mood, and more. Let’s see what the science and clinical evidence say about this supplement…



  • May help with depression
  • May reduce pain
  • May boost mental clarity


  • Not well studied in humans
  • Dangerous for people with phenylketonuria

How Does DLPA Work?

L-phenylalanine builds neurotransmitters such as dopamine and noradrenaline that control mood, mental health, heart rate, and other vital functions [6, 7].

As a supplement, it may help with depression and skin pigmentation, while there’s insufficient evidence for its effects on weight control and attention disorders [8, 9, 10].

The body converts about ⅓ of D-phenylalanine into the L-form, while the rest remains unchanged and has unique effects. Supplementation with D-phenylalanine may increase natural opioids, enkephalins, and reduce inflammation [4, 11].

Researchers have investigated its effects on chronic pain, mental disorders, and substance dependence, but the results weren’t convincing [12, 13].

In theory, DLPA should deliver the combined health benefits of both forms with fewer side effects, but there’s no substantial evidence to back this up.

DLPA Benefits

Possibly Effective:

1) Depression

Your brain uses L-phenylalanine in DLPA to produce mood-boosting neurotransmitters such as dopamine and noradrenaline. Low brain levels of these chemicals often lurk behind the symptoms of depression [6, 14].

In one clinical trial with 155 depressed patients, a combination of L-phenylalanine (250 mg daily) and standard treatment was beneficial in 80-90% of the cases [8].

DLPA (150-200 mg/day) had the same effect as an antidepressant, imipramine, in 40 depressed patients. However, the authors pointed to study design flaws that may have skewed the results [15].

DL-phenylalanine (75-200 mg/day for 20 days) resolved the symptoms of depression in 12 out of 20 patients. It offered mild to moderate benefits in four more patients, while it failed to affect the remaining four [16].

Lower doses of the same supplement (50-100 mg daily for 15 days) restored normal mood in 17 out of 23 depressed patients who didn’t respond to standard treatment [17].

The above studies are over 40 years old and lack placebo controls. We should take their results with a large grain of salt. Further research should investigate the potential antidepressant effects of L-phenylalanine and DLPA.

Insufficient Evidence:

No valid clinical evidence supports the use of DLPA for any of the conditions in this section. Below is a summary of up-to-date animal studies, cell-based research, or low-quality clinical trials which should spark further investigation. However, you shouldn’t interpret them as supportive of any health benefit.

2) Substance Dependence

Our internal opioids don’t just block pain signals, they regulate a deep-seated reward system in our brain that makes certain things enjoyable [18].

By increasing the levels of internal opioids, D-phenylalanine may improve mood and help people undergoing opiate withdrawal. The clinical data is limited and inconclusive [19, 12].

In 20 patients struggling with alcohol withdrawal, a supplement with D-phenylalanine, 5-HTP, and glutamine greatly reduced their psychiatric symptoms and stress [13].

The effect was likely due to increased brain levels of dopamine and enkephalins.

A group of scientists observed the ability of D-phenylalanine and hydrocinnamic acid to reduce alcohol addiction in mice by recovering internal opioids [20].

DLPA is 50% D-phenylalanine so it might deliver the same benefits, but there’s no clinical evidence to back this up.

3) Weight Loss

Some people use DLPA supplements to burn fat and lose weight despite the lack of clinical data to support its efficacy.

According to a handful of small trials, L-phenylalanine may reduce food intake and support fat burning [9, 21, 22, 23, 24].

As a source of this amino acid, DLPA might have the same effects, but no studies have confirmed this yet.

Possibly Ineffective:

4) Pain Management

D-phenylalanine – the other half of DLPA – raises the levels of our internal opioids. This led researchers to investigate its painkiller effects, but the results from clinical trials were discouraging [19, 25, 26, 27].

Some doctors have reported positive results in pain management with large doses (1,500-3,000 mg daily) of DLPA. According to them, antidepressant and painkiller effects of DLPA are tightly linked. However, we can’t draw any conclusions from these case reports [28].

Bottom line? DLPA doesn’t seem to be effective for pain management in the light of available evidence.

5) Attention Disorders

Low dopamine is one of the triggers of ADHD. In theory, phenylalanine may help with ADHD and other attention disorders by supplying dopamine [29].

In one older analysis, 44 children with ADHD had lower blood and urine phenylalanine levels than their healthy peers. But according to a more recent study, children with ADHD have normal phenylalanine levels [30, 31].

DLPA improved symptoms such as anger, restlessness, and poor concentration in 19 adults with ADHD. However, 3 months after the study finished, the beneficial effects disappeared [32].

D-phenylalanine had no beneficial effects on 19 hyperactive boys in another study. A review of clinical trials found no significant benefits of phenylalanine for ADHD [33, 34].

Based on the available research, phenylalanine and DLPA don’t help with ADHD symptoms.

DLPA Side Effects & Safety

This list does not cover all possible side effects. Contact your doctor or pharmacist if you notice any other side effects. In the US, you may report side effects to the FDA at 1-800-FDA-1088 or at www.fda.gov/medwatch. In Canada, you may report side effects to Health Canada at 1-866-234-2345.

Clinical trials reported no significant DLPA side effects [17, 16, 15, 32].

L- and D-phenylalanine as single supplements are also safe and well-tolerated [10, 34].

L-phenylalanine may cause nausea in higher doses and interact with a drug for Parkinson’s disease, L-DOPA. The same might go for DLPA [22, 35].

Although DLPA is safe in general, there’s a massive exception to this rule!

People with a rare metabolic disorder – phenylketonuria (PKU) – are unable to process phenylalanine properly. The accumulation of this amino acid can cause brain damage and cognitive impairment in PKU patients [36, 37, 38].

These people follow a special low-protein diet to minimize the intake of phenylalanine. Obviously, they should steer clear of DLPA other phenylalanine supplements [39, 40].

Children and pregnant women should also avoid DLPA due to the lack of safety data.

Drug Interactions

Supplement-drug interactions can be dangerous and, in rare cases, even life-threatening. Always consult your doctor before supplementing and let him know about all drugs and supplements you are using or considering.

Phenylalanine interacts with L-DOPA, a drug for Parkinson’s disease. It hinders the transport of L-DOPA to the brain, which may cause sharp changes in a clinical response known as the “on-off” phenomenon [35].

The fact that some people use phenylalanine supplements for Parkinson’s disease makes this interaction particularly important and dangerous. DLPA might not have the same effects, but caution is warranted.

DLPA Supplements

DLPA supplements have not been approved by the FDA for medical use. In general, regulatory bodies aren’t assuring the quality, safety, and efficacy of supplements. Speak with your doctor before supplementing.

Most supplements contain pills with 500-1,000 mg of DLPA. Bulk powder with 375 mg per serving is also available.


The below doses may not apply to you personally. If your doctor suggests using DLPA, work with them to find the optimal dosage according to your health condition and other factors.

The following DLPA dosage had some beneficial effects in clinical trials:

  • Depression: 50-200 mg for 2-4 weeks [15, 16, 17]
  • Attention Deficit Disorder: increasing from 150 to 1,200 mg daily for 2 weeks [32]
  • Chronic pain: 1,500-3,000 mg daily (from clinical experience) [28]

User Reviews

The opinions expressed in this section are solely from the users who may or may not have a medical background. SelfDecode does not endorse any specific product, service, or treatment. Do not consider user experiences as medical advice. Never delay or disregard seeking professional medical advice because of something you have read on SelfDecode.

Plenty of users have reported success with depression and mood disorders, although they mostly use DPLA in combination with other supplements such as fish oil, 5-HTP, and B vitamins.

Others take it to boost mental clarity and ease chronic pain, and they report mild improvements.

On the other hand, some users experienced no benefits from DLPA supplements. The most common side effects include:

  • Headache
  • Irritability
  • Nausea

Is DLPA Better Than L-Phenylalanine?

In theory, DLPA should deliver additional benefits compared with L- phenylalanine, but the evidence tells a different story.

Depression Weight loss Pain Addiction ADHD Vitiligo


In summary:

  • They both may help combat depression
  • L-phenylalanine may help burn fat and reduce vitiligo
  • DLPA might with ADD in adults, but the evidence is scant

How Long Does it Take to Work?

It depends on the condition, but in most cases, you can expect the first results after 2 weeks. The effects of DLPA may fade out over time, but it’s suitable for long-term use [32, 15, 17].

Where to Buy Phenylalanine


DLPA supplements contain 2 symmetric forms of phenylalanine, which provide building blocks for proteins and neurotransmitters. It may help with milder forms of depression, while there’s insufficient evidence for substance dependence and weight loss.

Clinical research doesn’t support the use of DLPA for attention disorders and pain management.

DLPA is generally safe and well-tolerated. Due to L-phenylalanine content, it may cause nausea and interact with Parkinson’s disease medications. People with phenylketonuria, children, and pregnant women should avoid it, while others should consult with their doctor first.

About the Author

Aleksa Ristic

Aleksa Ristic

MS (Pharmacy)
Aleksa received his MS in Pharmacy from the University of Belgrade, his master thesis focusing on protein sources in plant-based diets.  
Aleksa is passionate about herbal pharmacy, nutrition, and functional medicine. He found a way to merge his two biggest passions—writing and health—and use them for noble purposes. His mission is to bridge the gap between science and everyday life, helping readers improve their health and feel better.


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