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.


Overview Information

Tyrosine is an amino acid. Amino acids 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 most commonly used in protein supplements for an inherited disorder called phenylketonuria (PKU). It is also used for alcoholism, cocaine dependence, and memory and thinking skills, but there is no good scientific evidence to support these uses.

How does it work?

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


Uses & Effectiveness?

Effective for

  • An inherited disorder that increases levels of phenylalanine in the blood (phenylketonuria or PKU). People with PKU are not able to process the amino acid phenylalanine. This amino acid is used by the body to make tyrosine. Because of this, people with PKU can have low levels of tyrosine in the body. To prevent tyrosine levels from becoming too low, people with PKU are advised to consume medical foods containing tyrosine but very little phenylalanine. Tyrosine levels in the blood are regularly measured by physicians.

Possibly Effective for

  • Memory and thinking skills (cognitive function). Research shows that taking tyrosine might improve mental performance, usually under stressful conditions These include cold-induced stress or noise-induced stress.
  • Memory. Research shows that taking tyrosine improves memory during stressful conditions. These include cold-induced stress or multi-tasking. Tyrosine does not seem to improve memory during less stressful situations.
  • Lack of sleep (sleep deprivation). Taking tyrosine helps people who have lost a night's sleep stay alert for about 3 hours longer than they otherwise would. Also, early research shows that tyrosine improves memory and reasoning in people who are sleep-deprived.

Possibly Ineffective for

  • Athletic performance. Taking tyrosine before running or cycling does not seem to improve strength, stamina, or performance.
  • Attention deficit-hyperactivity disorder (ADHD). Taking tyrosine by mouth does not seem to improve symptoms in children or adults with ADHD.
  • Depression. Taking tyrosine by mouth does not improve symptoms of depression.

Insufficient Evidence for

  • Alcohol use disorder. Early research shows that taking tyrosine along with other amino acids and a multivitamin reduces withdrawal symptoms and stress in alcoholics. It is not clear if this effect is due to tyrosine, other ingredients, or the combination.
  • Cocaine use disorder. Early research shows that taking tyrosine in the morning and L-tryptophan at night does not reduce cravings or withdrawal symptoms in people with cocaine dependence.
  • Diseases, such as Alzheimer disease, that interfere with thinking (dementia). Early research shows that taking tyrosine, 5-hydroxytryptophan, and carbidopa by mouth does not improve symptoms in people with dementia.
  • High blood pressure. Early research shows that taking tyrosine by mouth does not reduce blood pressure in people with slightly high blood pressure.
  • Excessive daytime sleepiness (narcolepsy). Research shows that taking tyrosine by mouth reduces some symptoms of narcolepsy, such as feelings of tiredness, based on patient ratings. But it does not seem to improve most symptoms based on clinical assessment.
  • Schizophrenia. Early research shows that taking tyrosine along with the drug molindone does not improve symptoms of schizophrenia better than molindone alone.
  • Skin wrinkles from sun damage. Applying a preparation containing 10% vitamin C, acetyl tyrosine, zinc sulfate, sodium hyaluronate, and bioflavonoids seems to improve wrinkling, skin yellowing, roughness, and skin tone in people with sun-damaged skin.
  • Alzheimer disease.
  • Chronic fatigue syndrome (CFS).
  • Erectile dysfunction (ED).
  • Heart disease.
  • Obesity.
  • Parkinson disease.
  • Premenstrual syndrome (PMS).
  • Stress.
  • Withdrawal from heroin, morphine, and other opioid drugs.
  • Other conditions.
More evidence is needed to rate the effectiveness of tyrosine for these uses.

Side Effects

Side Effects & Safety

When taken by mouth: Tyrosine is LIKELY SAFE when taken in food amounts. It is POSSIBLY SAFE when taken by adults as a medicine, short-term. Tyrosine seems to be safe when taken in doses up to 150 mg/kg daily for up to 3 months. Some people experience side effects such as nausea, headache, fatigue, and heartburn.

When applied to the skin: Tyrosine is POSSIBLY SAFE when applied to the skin.

Special Precautions & Warnings:

Pregnancy and breast-feeding: There isn't enough reliable information to know if tyrosine is safe to use when pregnant or breast-feeding. Stay on the safe side and stick to food amounts.

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.



Moderate Interaction

Be cautious with this combination

  • Levodopa interacts with TYROSINE

    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 hormone interacts with TYROSINE

    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 memory and thinking skills (cognitive function): A single dose of 100-300 mg/kg or 2 grams of tyrosine has been taken before a stressful mental task.
  • For memory: 150-300 mg/kg of tyrosine has been used before a memory task.
  • For lack of sleep (sleep deprivation): 150 mg/kg of tyrosine in a split dose has been used.
  • For an inherited disorder that increases levels of phenylalanine in the blood (phenylketonuria or PKU): Foods and medical foods providing 4-6 grams of tyrosine daily are recommended. Women with PKU who are pregnant or breastfeeding are advised to consume foods providing 6-7.6 grams of tyrosine daily. A doctor will measure tyrosine levels in the blood to make sure they don't become too high or too low. For most people with PKU, additional separate supplementation with free tyrosine is not recommended. It can cause wide variations in the amount of tyrosine in the blood. This could cause unwanted side effects.

  • For an inherited disorder that increases levels of phenylalanine in the blood (phenylketonuria or PKU): Foods and medical foods providing tyrosine 1.1-6.0 grams daily, depending on age, are recommended from infancy. A doctor will measure tyrosine levels in the blood to make sure they don't become too high or too low. For most people with PKU, additional separate supplementation with free tyrosine is not recommended. It can cause wide variations in the amount of tyrosine in the blood. This could cause unwanted side effects.

View References


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