Tyrosine is a precursor to major neurotransmitters and can help reduce dopamine-related depression, ADHD, and extreme stress.
Tyrosine, also known as l-tyrosine, is a naturally occurring compound of primary importance for mental health.
It’s a precursor to some of your most important brain chemicals and hormones.
The US military has tested tyrosine and found it exceptional for increasing resilience to extreme stress.
Here’s a look at this and other benefits of tyrosine, how to get more tyrosine from your diet, and what you need to know about tyrosine supplementation.
What Is Tyrosine?
Tyrosine is an amino acid involved in the structure of almost every protein in the body.
It gets its name from the Greek word tyros for cheese, since it was first discovered in cheese protein.
Most amino acids are categorized as essential (you need to get it from food) or non-essential (your body makes its own).
Tyrosine is one of the handful of conditional amino acids.
This means that your body can usually make what it needs, but not always in adequate amounts.
Stress, overwork, lack of sleep, illness, or eating too little protein can all increase your need for tyrosine. (1)
There are two primary sources of tyrosine — from the food you eat and from the breakdown of phenylalanine, one of the 9 essential amino acids.
Tyrosine is a precursor to three important neurotransmitters — dopamine, epinephrine, and norepinephrine.
Neurotransmitters are chemicals that brain cells use to communicate with each other.
They have profound effects on every aspect of your life.
Tyrosine is also the precursor to the thyroid hormones triiodothyronine (T3) and thyroxine (T4). (2)
Lastly, tyrosine is the fundamental component of melanin, the pigment that colors your hair, eyes, and skin.
An Overview of Tyrosine Benefits and Uses
People take tyrosine supplements for a wide variety of brain-related and mental health conditions.
It’s commonly used for stress, depression, attention disorders, narcolepsy, Alzheimer’s disease, Parkinson’s disease, and to ease withdrawal symptoms when quitting addictive substances. (3)
It is also used for chronic fatigue syndrome, heart disease, premenstrual syndrome, and sexual dysfunction.
Reported subjective benefits of tyrosine include enhancement of memory, focus, stamina, alertness, and motivation, as well as the suppression of appetite and anxiety. (4)
It improves working memory but, oddly, only in situations where performance is compromised by stress such as with multitasking. (7)
It may be neuroprotective and is being considered as a way to halt neurological decline in dementia patients. (8)
Low levels of tyrosine have been linked to autism. (9)
Now let’s take an in-depth look at the five most important benefits and proven uses for tyrosine.
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1. Tyrosine Is the Precursor to Key Neurotransmitters
Tyrosine is an essential building block for a group of neurotransmitters known as catecholamines.
The three catecholamines are dopamine, norepinephrine, and epinephrine.
By providing the raw material needed for their synthesis, tyrosine helps maintain healthy brain chemistry.
Research confirms that tyrosine is actively transported across the blood-brain barrier where it increases dopamine, norepinephrine, and epinephrine in the brain.
Here’s a diagram of this chain of events from start to finish.
The amount of tyrosine available to the brain affects the synthesis of the catecholamine brain chemicals. (12)
However, simply increasing the amount of tyrosine in your body does not automatically increase neurotransmitter production.
Their synthesis is regulated by complicated biochemical feedback loops to keep neurotransmitter levels balanced. (13)
However, it seems that adding more tyrosine does provide a safety net that helps to prevent neurotransmitter depletion. (14)
Here’s a quick look at why these neurotransmitters are so important and why you don’t want to have suboptimal levels.
Dopamine plays a role in mood, sleep, learning, memory, focus, and motor control.
It’s called the “motivation molecule” since it provides the drive you need to be productive.
Dopamine is in charge of your brain’s pleasure-reward system.
Dopamine dysfunction is linked to depression, attention deficit hyperactivity disorder (ADHD), schizophrenia, bipolar disorder, substance abuse, and degenerative brain diseases. (15)
Norepinephrine is a dual-purpose chemical that acts as both a neurotransmitter and a stress hormone.
Norepinephrine, along with epinephrine (aka adrenaline), triggers the fight-or-flight response when you are in perceived danger.
It increases heart rate, blood pressure, breathing rate, muscle strength, and mental alertness to get you ready to face extreme stress.
Too little norepinephrine has been linked to depression and ADHD; too much contributes to anxiety.
2. Tyrosine Helps Dopamine-Related Depression
The prevailing theory is that depression is caused by too little serotonin.
But the medical community is finally coming around to the idea that depression may have other underlying causes such as brain inflammation, low dopamine, and/or low norepinephrine. (16)
Most prescription antidepressants are selective serotonin reuptake inhibitors (SSRIs) that work by increasing serotonin levels.
But other antidepressants act on dopamine, norepinephrine, or a combination of neurotransmitters.
Cymbalta (duloxetine) works by increasing both norepinephrine and serotonin. (19)
Tyrosine is a good natural antidepressant to consider if your depression is due to low levels of dopamine or norepinephrine rather than serotonin.
But how can you tell?
For now, there are no reliable lab tests that can pinpoint which neurotransmitter imbalance is the cause of your depression.
However, using symptoms to assess your situation works surprisingly well.
Depression from low serotonin is usually accompanied by anxiety.
Depression from low levels of catecholamines — dopamine or norepinephrine — manifests as feelings of apathy, lethargy, and lack of zest for life instead.
You’ll know soon enough if tyrosine is the answer for you because it works surprisingly fast.
One study on patients with dopamine-dependent depression found that they experienced improvements in mood within one day after taking tyrosine! (20)
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3. Tyrosine Overcomes the Effects of Extreme Stress
There is little evidence that tyrosine will help your mental or physical performance under normal circumstances.
But if you are facing acute physical or mental stress, it can be a potent anti-stress supplement.
There’s been a surprising amount of research done on the effects of tyrosine as a buffer against the harmful effects of extreme stress.
Most of these studies were performed by the US and other militaries to help personnel maintain a high level of performance under a variety of severely stressful circumstances. (21)
So far it’s been determined that tyrosine can prevent the performance impairment, fatigue, adverse moods, and cognitive decline that occurs in response to physical stressors such as extreme cold, oxygen deprivation, high altitude, sleep deprivation, and the low gravity experienced in space. (22, 23, 24, 25, 26)
Tyrosine reduced stress and fatigue, lowered blood pressure, and improved cognitive task performance during a demanding military combat training course. (27)
Tyrosine was even put to the test in Antarctica, the harshest environment on the planet.
Unsurprisingly, mood among those who stay there during the winter plummets.
But when year-long residents were given tyrosine, they experienced a significant 47% improvement in mood. (28)
However, tyrosine did not help mood during the Antarctic summer which apparently is not sufficiently stressful.
In a sleep deprivation study, participants were kept awake for 24 hours straight.
Those given tyrosine did not show the typical decline in mental performance, motor skills, or mood. (29)
Tyrosine is often taken by athletes, but a review of 15 studies found no significant effects of tyrosine on exercise performance. (30)
It’s thought that tyrosine improves physical performance only when the exercise produces enough stress to deplete dopamine or norepinephrine levels. (31)
4. Tyrosine Is an Adjunct Treatment for ADHD
It is widely accepted that the root cause of ADHD is dopamine dysfunction. (32)
Most prescription ADHD medications are based on the “dopamine deficiency” theory.
They work by stimulating the release of the neurotransmitters dopamine and norepinephrine. (33)
Treating ADHD with tyrosine, the precursor to dopamine, shows promise.
So far the evidence points to tyrosine being a useful adjunct to other ADHD treatments.
In one study on ADHD, children were given tyrosine along with 5-HTP, a supplement that is a precursor of serotonin. (34)
An impressive 67% experienced significant improvement in ADHD symptoms from this amino acid combination.
Another study found that taking tyrosine plus the medication Ritalin worked better at increasing dopamine than Ritalin alone. (35)
One study in adults with ADHD found that tyrosine initially helped with symptoms, but most study participants developed a tolerance and it quit working after six weeks. (36)
5. Tyrosine Is Essential in Treating PKU
Tyrosine is essential for treating phenylketonuria (PKU), a rare inherited amino acid disorder.
People with PKU lack an enzyme that breaks down the amino acid phenylalanine which results in its toxic buildup.
If left untreated, PKU can cause brain damage.
There is no cure for PKU, but it is largely controlled by severely restricting phenylalanine in the diet. (37)
Since tyrosine is found in protein-rich foods and synthesized from phenylalanine, tyrosine deficiency often results.
For this reason, tyrosine supplementation is usually prescribed. (38)
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The Top Tyrosine Food Sources
Tyrosine is found mainly in protein-rich foods.
Virtually all animal products — meat, fish, poultry, eggs, and dairy — are good sources of tyrosine.
Top plant sources include soy products, pumpkin seeds, sesame seeds, peanuts, almonds, avocados, bananas, and the sea vegetable spirulina. (39)
The Best Form of Tyrosine Supplements
Unlike many other natural supplements, tyrosine works very quickly.
There are two main forms of tyrosine supplements available — l-tyrosine and n-acetyl l-tyrosine (NALT).
The NALT form is particularly popular as both a nootropic and as a performance enhancer for athletes and bodybuilders.
There are a lot of claims that NALT is the superior form since it’s highly soluble in water. (42)
But this solubility does not translate into bioavailability.
Research shows that when compared to three other forms of tyrosine, NALT is the least effective at raising blood levels of tyrosine. (43)
This makes sense when you consider that your body must break down NALT into l-tyrosine before it can be used, and this is an inefficient process.
One study found that 56% of the NALT gets excreted rather than broken down into l-tyrosine. (44)
Since literally half of the NALT you take goes down the toilet, I recommend sticking with the l-tyrosine form.
There is no Recommended Dietary Allowance (RDA) for tyrosine, but tyrosine supplements typically come in 500 mg doses. (45)
Tyrosine is best taken on an empty stomach 30 minutes before meals and divided into 3 daily doses.
Taking tyrosine on an empty stomach ensures that some is available to create neurotransmitters.
Taking it along with the needed cofactors vitamin B6, vitamin B9 (folate), and copper helps to optimize its conversion into neurotransmitters as well. (46)
The current rule of thumb for people with PKU is 6 grams of tyrosine per 100 grams of dietary protein. (47)
However, if you have PKU, do not self-administer.
Discuss exactly how much tyrosine you should be taking with your doctor.
Tyrosine Safety: Side Effects and Interactions
While tyrosine is generally safe, reported side effects include nausea, headache, fatigue, heartburn, and joint pain. (48)
It can worsen some symptoms of schizophrenia. (49)
There’s currently not enough information to determine whether it’s safe for children, pregnant women, or breastfeeding mothers, so in these cases, it’s best to avoid it.
You should not take tyrosine if you have hyperthyroidism or Graves disease.
When taken with thyroid medications, supplemental tyrosine can cause thyroid hormone levels to get too high.
It is critical that you not take tyrosine if you are taking a monoamine oxidase inhibitor (MAOI), a medication sometimes prescribed for depression, anxiety disorders, and Parkinson’s. (50)
Taken together, they can cause a severe increase in blood pressure that can lead to a heart attack or stroke.
Tyrosine should not be taken with levodopa, a medication used to treat Parkinson’s disease, since it might decrease this drug’s effectiveness. (51)
Finally, since it is a precursor for dopamine and norepinephrine, tyrosine may interact with or enhance the effects of drugs that affect their production. (52)
Tyrosine Benefits: Take the Next Step
Tyrosine is an amino acid that provides the building blocks for the neurotransmitters dopamine, norepinephrine, and epinephrine.
It’s a fast-acting natural antidepressant for dopamine-related depression and shows promise for treating ADHD.
Human studies repeatedly show that tyrosine excels at countering the effects of extreme physical and psychological stress.
You can get the tyrosine you need from eating protein-rich foods or by taking a quality tyrosine supplement.
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