Last Editorial Review: 6/11/2021
Other Name(s):

2-Acetylamino-3-(4-Hydroxyphenyl)-Propanoic Acid, Acetyl-L-Tyrosine, Acétyl-L-Tyrosine, L-Tyrosine, N-Acetyl L-Tyrosine, N-Acetyl-L-Tyrosine, N-Acétyl L-Tyrosine, N-Acetyl-Tyrosine, N-Acétyl-Tyrosine, Tirosina, Tyr, Tyrosinum, 2-amino-3-(4-hydroxyphenyl)propionic acid.


Tyrosine is one of the amino acids, which are the building blocks of protein. The body makes tyrosine from another amino acid called phenylalanine. Tyrosine can also be found in dairy products, meats, fish, eggs, nuts, beans, oats, and wheat.

Tyrosine is used in protein supplements to treat an inherited disorder called phenylketonuria (PKU). People who have this problem can't process phenylalanine properly, so as a result they can't make tyrosine. To meet their bodies' needs, supplemental tyrosine is given.

People take tyrosine for depression, attention deficit disorder (ADD), attention deficit-hyperactivity disorder (ADHD), the inability to stay awake (narcolepsy), and improving alertness following sleep deprivation. It is also used for stress, premenstrual syndrome (PMS), Parkinson's disease, Alzheimer's disease, chronic fatigue syndrome (CFS), alcohol and cocaine withdrawal, heart disease and stroke, ED (erectile dysfunction), loss of interest in sex, schizophrenia, and as a suntan agent and appetite suppressant.

Some people also apply tyrosine to the skin to reduce age-related wrinkles.

How does it work?

The body uses tyrosine to make chemical messengers that are involved in conditions involving the brain such as mental alertness.


Why do we sleep? See Answer

Uses & Effectiveness

Effective for...

  • Phenylketonuria (PKU). People with PKU are not able to process the amino acid phenylalanine, which is used by the body to make tyrosine. Because of this, people with PKU can have low levels of tyrosine in the body. People with PKU are advised to consume 6 grams of tyrosine per 100 grams of protein to improve tyrosine levels in the body.

Possibly Effective for...

  • Mental performance. Some early research suggests that taking tyrosine 2 hours before testing does not improve mood or speed of reaction to visual or noise stimuli in healthy people. However, several studies show that tyrosine improves mental performance under stressful conditions, such as military training, cold-induced stress, or noise-induces stress.
  • Memory. Some early research suggests that taking tyrosine 2 hours before testing does not improve memory in healthy people. However, several studies show that tyrosine improves memory under stressful conditions, such as cold-stress or multitasking.
  • Improving alertness following the loss of sleep. Taking 150 mg/kg of tyrosine seems to help people who have lost a night's sleep stay alert for about 3 hours longer than they otherwise would. Also, early research suggests that tyrosine improves memory and reasoning in people who are sleep-deprived.

Possibly Ineffective for...

  • Attention deficit disorder (ADD). Taking tyrosine by mouth does not seem to improve symptoms of adult ADD.
  • Attention deficit-hyperactivity disorder (ADHD). Taking tyrosine by mouth does not seem to improve symptoms of childhood ADHD.
  • Depression. Taking tyrosine by mouth does not seem to improve symptoms of moderate depression.
  • Exercise performance. Taking tyrosine before participating in treadmill walking with a load carriage does not seem to improve strength or endurance. Also, taking tyrosine, alone or with polydextrose 70, does not seem to improve heart rate or performance during a cycling test.

Insufficient Evidence to Rate Effectiveness for...

  • Alcoholism. Early research suggests that taking a combination of D,L-phenylalanine, L-tyrosine, L-glutamine, and L-tryptophan along with a multivitamin might help reduce symptoms of withdrawal and decrease stress in alcoholics.
  • Cocaine dependence. Early research suggests that taking L-tyrosine in the morning and L-tryptophan at night does not reduce drug cravings or withdrawal symptoms in people with cocaine dependence.
  • Dementia. Early research suggests that taking a combination of tyrosine, 5-hydroxytryptophan (5-HTP), and carbidopa by mouth does not improve symptoms in people with severe dementia due to Alzheimer's disease or multi-infarct dementia.
  • High blood pressure (hypertension). Early research suggests that taking tyrosine by mouth does not affect blood pressure in patients with slightly high blood pressure.
  • Excessive sleepiness (narcolepsy). Research suggests that taking tyrosine by mouth might reduce some symptoms of narcolepsy, such as feelings of tiredness, based on patient ratings. However, it does not seem to improve most symptoms of narcolepsy based on clinical assessment.
  • Schizophrenia. Early research suggests that taking L-tyrosine along with the drug molindone for 3 weeks does not improve symptoms of schizophrenia better than molindone alone.
  • Weight loss. Taking a combination of tyrosine, cayenne, green tea, caffeine, and calcium for 8 weeks seems to slightly reduce body fat mass by 0.9 kg in overweight people. However, the combination supplement does not seem to improve blood pressure, heart rate, or the excretion of fat in the feces.
  • Wrinkled skin. A topical preparation containing 10% vitamin C as L-ascorbic acid, acetyl tyrosine, zinc sulfate, sodium hyaluronate, and bioflavonoids (Cellex-C High Potency Serum) applied for 3 months to facial skin aged by sunlight seems to improve fine and coarse wrinkling, yellowing, roughness, and skin tone.
  • Stress.
  • Premenstrual syndrome (PMS).
  • Parkinson's disease.
  • Chronic fatigue syndrome (CFS).
  • Alzheimer's disease.
  • Heart disease.
  • Erectile dysfunction (ED).
  • Other conditions.
More evidence is needed to rate the effectiveness of tyrosine for these uses.

Natural Medicines Comprehensive Database rates effectiveness based on scientific evidence according to the following scale: Effective, Likely Effective, Possibly Effective, Possibly Ineffective, Likely Ineffective, and Insufficient Evidence to Rate (detailed description of each of the ratings).

Side Effects

Tyrosine is LIKELY SAFE when taken by mouth in food amounts and POSSIBLY SAFE when taken by adults short-term in medicinal amounts or when applied to the skin. Tyrosine seems to be safe when used in doses up to 150 mg/kg per day for up to 3 months. Some people experience side effects such as nausea, headache, fatigue, heartburn, and joint pain.

There isn't enough information available to know if tyrosine is safe for children to use in medicinal amounts. Don't give it to children without the advice of your healthcare provider until more is known.


Sleep Disorders: Foods That Help Sleep or Keep You Awake See Slideshow

Special Precautions & Warnings

Pregnancy and breast-feeding: There isn't enough information available to know if tyrosine is safe to use during pregnancy and breast-feeding. Stay on the safe side and avoid use.

Overactive thyroid (hyperthyroidism) or Graves disease: The body uses tyrosine to make thyroxine, a thyroid hormone. Taking extra tyrosine might increase thyroxine levels too much, making hyperthyroidism and Graves disease worse. If you have one of these conditions, don't take tyrosine supplements.


LevodopaInteraction Rating: Moderate Be cautious with this combination.Talk with your health provider.

Tyrosine might decrease how much levodopa the body absorbs. By decreasing how much levodopa the body absorbs, tyrosine might decrease the effectiveness of levodopa. Do not take tyrosine and levodopa at the same time.

Thyroid hormoneInteraction Rating: Moderate Be cautious with this combination.Talk with your health provider.

The body naturally produces thyroid hormones. Tyrosine might increase how much thyroid hormone the body produces. Taking tyrosine with thyroid hormone pills might cause there to be too much thyroid hormone. This could increase the effects and side effects of thyroid hormones.


The following doses have been studied in scientific research:


  • For improving alertness after being without sleep for a long time: 150 mg/kg/day of tyrosine.
  • For PKU: The current recommendation for people with PKU is the incorporation of 6 grams of tyrosine per 100 grams of protein. However, additional separate supplementation with free tyrosine is not recommended because it can produce wide variations in the amount of tyrosine in the blood and could cause unwanted side effects.

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