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 .
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].
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?
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].
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.
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 .
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 .
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 .
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 .
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.
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 .
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 .
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.
As a source of this amino acid, DLPA might have the same effects, but no studies have confirmed this yet.
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 .
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 .
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 .
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.
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].
Children and pregnant women should also avoid DLPA due to the lack of safety data.
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 .
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 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 
- Chronic pain: 1,500-3,000 mg daily (from clinical experience) 
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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:
Is DLPA Better Than L-Phenylalanine?
In theory, DLPA should deliver additional benefits compared with L- phenylalanine, but the evidence tells a different story.
- 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?
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.