N-acetyl-L-tyrosine is also known by its abbreviation, NALT. NALT is a modified version of the amino acid L-tyrosine, which is itself one of the biologically available forms of tyrosine. Supplementing with L-tyrosine is believed to help reduce stress and improve mental performances, especially when the body is taxed or under stressful circumstances such as cold weather.


Tyrosine is classified as a non-essential amino acid. As such, it does not necessarily have to be obtained through your diet. Your body is able to synthesize it as it needs the amino acid, from phenylalanine, which is unlike some other amino acids that are only obtained by what you eat.

You can obtain tyrosine through a variety of foods. Tyrosine was first discovered in cheese, which is where the name comes from; “tyros” in Greek means cheese. It can also be found in a variety of other foods, especially high protein foods such as chicken, dairy products, and fish. You can also purchase tyrosine as a dietary supplement, which comes in different forms.

Tyrosine is important because it is used to make several different compounds in the body, particularly certain neurotransmitters and hormones. It is chiefly responsible for making dopamine, which is important in forming memories and handling motor skills. Tyrosine is also used to make adrenaline and noradrenaline, which are used to respond to stressful situations. Thyroid hormones are also made from tyrosine, and melanin is another compound, one that gives pigment to your skin and hair.

N-Acetyl-L-Tyrosine vs. L-Tyrosine

With multiple forms of tyrosine available, you’re probably wondering differentiates N-acetyl-L-tyrosine versus L-tyrosine. In short, there is an additional acetyl group known as acetic acid that is in N-acetyl-L-tyrosine. This group makes NALT more bioavailable. The acetic acid group attached to the L-tyrosine structure makes NALT more readily absorbed into your bloodstream. It can do this because it is 20 times more water soluble than other forms of tyrosine, such as L-tyrosine.

Theoretically, with increased bioavailability, taking NALT would have greater effects than taking L-tyrosine alone. Within the body, NALT gets broken into L-tyrosine, which can then go and have its effects on the brain, such as improving mood.

Effects of Tyrosine in Stressful Situations

Tyrosine, in any of its forms, can help your body to better handle stressful situations, with NALT improving performance. Studies have shown that under stressful situations, your body’s performance decreases, largely related to a decrease in the presence of neurotransmitters. Increasing your consumption of NALT will lead to a greater amount of neurotransmitters in your body, reversing this trend.

In one study, working memory was tested, which plays a role in concentration, and your ability to follow instructions. During the study, tyrosine supplementation led to an improved working memory, compared to a placebo, during a demanding task.

Tyrosine also improved the ability to switch between different tasks or thoughts, which is a process known as cognitive flexibility. A study has shown that it is more effective than a placebo regarding mental flexibility. Unfortunately, all of these studies have been done when the body is under stressful circumstances, tyrosine alone won’t increase your brainpower.

Tyrosine May Have Effects on Depression

Much of the research into tyrosine supplementation and depression has been mixed. Some studies have shown that tyrosine is no more effective than a placebo for people with depression, while people taking a common antidepressant had improvement in their symptoms. Depression has many causes, and tyrosine may not be treating the underlying cause.

For some people, tyrosine may be beneficial, especially if they have a depression that is linked to a deficiency in dopamine. Dopamine-dependent depression is linked to having low energy levels, and is often characterized by the sufferer having a lack of motivation. In one study, people with dopamine-dependent depression did better when supplemented with tyrosine, likely because the supplement increases levels of dopamine in the body.

N-Acetyl-L-Tyrosine Side Effects

NALT tends to be considered a rather safe supplement. The dosage that has been studied, and found to be safe for those taking it, is 68 mg per pound or 150 mg per kilogram of body weight. This dosage has been studied for durations of up to three months, and has shown no adverse effects.

Unfortunately some medications and tyrosine may interfere with each other. The main drug class that people may find issues with is with monoamine oxidase inhibitors or MAOIs. MAOIs are designed to block the enzyme monoamine oxidase, one of the effects of which is used to break down excess tyramine in the body. Tyramine gets formed when tyrosine is broken down, and can affect blood pressure. By increasing the amounts of tyramine in the body, your blood pressure may increase to a dangerous level.

NALT may also affect people with an overactive thyroid, or people who are taking thyroid medication. Because L-tyrosine is a precursor to thyroid hormones, supplementing with NALT may lead to higher than normal levels of thyroid hormones.

NALT may also have effects on people taking Levodopa or L-dopa, a medication that is used to help treat Parkinson’s disease. Tyrosine competes with Levodopa for absorption within the small intestine. Taking the two together can mean that lower than effective amounts of the drug and supplement are absorbed. To get around that, taking the two medications should be separated by at least several hours, to avoid interactions.

At high doses, NALT can also cause gastrointestinal upset. To minimize the chance of having an upset stomach from taking tyrosine, you can split the dosage, taking it at two times, separated by at least 30 minutes. NALT may also cause migraine sufferers to have more headaches. This trait is caused by increasing the concentration of neurotransmitters such as dopamine in the body.

As always, if you are thinking about taking a supplement, talk to your physician. This is especially true if you are already taking other medications that may interfere with the supplement.

In Summary

N-acetyl-L-tyrosine, or NALT is a common supplement that has the potential to have many benefits. Taking it before stressful situations can help improve your concentration, and multi-tasking ability, during the situation, while it may also be useful in helping some people with health conditions, such as depression related to low dopamine levels.

These statements have not been evaluated by the Food and Drug Administration. Products discussed are not intended to diagnose, treat, cure, or prevent any disease.