What is DL-phenylalanine?

DL-phenylalanine is a combination of two forms of the amino acid phenylalanine: D-phenylalanine and L-phenylalanine. It is commonly used as a dietary supplement for various health benefits.

How does it work?

DL-phenylalanine works by increasing the levels of neurotransmitters, such as dopamine and norepinephrine, in the brain. These neurotransmitters play a role in regulating mood, pain perception, and appetite.

What forms does it come in?

DL-phenylalanine is available in the form of capsules, tablets, and powder.

What can happen if I have an imbalance or deficiency?

A deficiency in phenylalanine can lead to a decrease in the production of important neurotransmitters, leading to various health problems.

What does DL-phenylalanine help with?

DL-phenylalanine, or DLPA, is a supplement made of two forms of one amino acid. The L-form is a building block the body uses for brain messengers. The D-form is not found in food and acts on the body's own pain-easing chemicals.

• White patches on the skin (vitiligo)
  Good evidence — several clinical trials, mostly paired with UV light therapy. Several clinical trials tested L-phenylalanine for vitiligo. It was given by mouth or put on the skin, often with UV light. These trials reported measurable return of skin colour.
  Evidence grade B · Traditional tier T0
• Widespread pain from fibromyalgia
  Early evidence — small clinical studies only. Small clinical studies looked at phenylalanine for fibromyalgia pain. The idea tested was that the D-form slows the enzyme that breaks down enkephalins. Early results looked hopeful, but more research is still needed.
  Evidence grade C · Traditional tier T0
• Sore, aching joints and arthritis pain
  Early evidence — small human studies in osteoarthritis and long-term joint pain. The D-form has been studied in osteoarthritis and long-term joint pain. Some of that work reported relief that mattered to people. It was often used with other natural approaches, so the effect of DLPA alone is hard to read.
  Evidence grade C · Traditional tier T0
• Long-term pain that has not eased with usual care
  Evidence doesn't support this — lab work on mechanism plus small, mixed human pain studies. In lab studies, the D-form slowed the enzymes that break down enkephalins. Enkephalins are the body's own pain-easing chemicals. Human studies in back and joint pain are small and mixed, so the picture is not settled.
  Evidence grade D · Traditional tier T0
• Low mood and depression
  Not yet tested in people — no human trial of DLPA on file; nutrient biochemistry only. L-phenylalanine is well established as a building block for dopamine and norepinephrine. Both tend to run low in people with depression, but that is general brain science, not a trial of DLPA. DLPA has also been linked to PEA, a compound tied to wellbeing, in early work rather than in trials.
  Evidence grade insufficient · Traditional tier T0
• Feeling flat, blunted or unmotivated
  Not yet tested in people — no human trial on file; based on the dopamine pathway. Dopamine is known to drive reward and motivation. DLPA supplies a building block the body uses to make it. No human study on file has tested whether DLPA changes how motivated people feel.
  Evidence grade insufficient · Traditional tier T0
• Support during alcohol withdrawal
  Not yet tested in people — practitioner use and early research; no trial size or dose on file. Heavy long-term drinking is known to disturb dopamine and enkephalin levels. Some integrative practitioners include DLPA in withdrawal plans for that reason. Early research has looked at cravings and mood, but the library holds no trial details.
  Evidence grade insufficient · Traditional tier T0
• Low energy and tiredness
  Not yet tested in people — user reports and nutrient biochemistry; no human trial on file. Dopamine and norepinephrine are known to support physical drive and alertness. Many users describe DLPA as a steadier lift than stimulants. Those are personal reports, not findings from a trial.
  Evidence grade insufficient · Traditional tier T0
• Focus and mental clarity
  Not yet tested in people — no human trial on file; based on the dopamine pathway. Dopamine and norepinephrine are known to matter for attention and working memory. DLPA is a precursor the body can use to make both. Some practitioners offer it as a gentler option, but no human study on file backs a focus effect.
  Evidence grade insufficient · Traditional tier T0

What DL-phenylalanine has not been shown to do

• No human trial on file shows DLPA lifts depression, so it is not a stand-in for antidepressant care.
• The vitiligo trials used UV light alongside it, so it has not been shown to restore skin colour on its own.
• No trial on file shows it raises energy, or that it works like a stimulant.
• No trial on file shows it helps ADHD, or that it can take the place of focus medicines.
• No trial on file shows it cuts alcohol cravings or shortens withdrawal.

How to read this:

The grades here rate the human evidence for each use, not how strong the product is. A means steady results across randomised trials in people. B means at least one good randomised trial. C means small or mixed human studies. D means weak or clashing human evidence. Insufficient means no human study on file, only lab work, body chemistry or practice habit. This page lists options and what studies found. It is not medical advice, and it is not a promise of results.

What does it help prevent?

• Depression
• Chronic fatigue
• Pain
• Opiate withdrawal
• Alcoholism
• Attention deficit hyperactivity disorder (ADHD)
• Parkinson's disease
• Obsessive-compulsive disorder (OCD)
• Osteoarthritis
• Migraines

Which foods are rich in it?

• Cheese
• Meat
• Eggs
• Fish
• Milk
• Nuts
• Soy products
• Beans
• Poultry
• Yogurt

What are possible side effects?

Common: Headache, Nausea, Insomnia

Mild: Dizziness, Tiredness, Dry mouth

Moderate: Blurred vision, Rapid heartbeat, Constipation

Severe: High blood pressure, Seizures, Chest pain

Overdose: Coma, Death

Withdrawal: Headache, Nausea, Insomnia

What's the recommended daily dose?

Adults: 500-2000 mg/day

How many days does it take to work?

The time it takes for DL-phenylalanine to work varies for each individual and depends on the condition being treated. It may take several days to several weeks to see results.

What time of day is best to take it?

It is recommended to take DL-phenylalanine with a meal, in the morning or afternoon.

Is it best to take it with or without food?

It is recommended to take DL-phenylalanine with a meal.