Tyrosine is an amino acid, which is a building block of protein that occurs naturally in the body. Tyrosine can also be found in certain foods such as meat, fish, eggs, dairy products, beans, nuts, oats, and wheat.

Some people have low levels of tyrosine in their bodies because of a hereditary condition called phenylketonuria (PKU). In people with PKU, the body cannot process an amino acid called phenylalanine, which the body needs to produce tyrosine.

Tyrosine is given as a supplement to increase tyrosine levels in people with PKU.

Tyrosine has been used in alternative medicine as a possibly effective aid in improving mental performance, alertness, or memory.

Tyrosine has also been used to treat depression or attention deficit disorder (ADD or ADHD). However, research has shown that tyrosine may not be effective in treating these conditions. Tyrosine also may not be be effective in improving exercise performance.

Other uses not proven with research have included dementia, high blood pressure, narcolepsy, schizophrenia, weight loss, premenstrual syndrome, Parkinson's disease, chronic fatigue syndrome, alcoholism, cocaine addiction, and other conditions.

It is not certain whether tyrosine is effective in treating any medical condition. Medicinal use of this product has not been approved by the FDA. Tyrosine should not be used in place of medication prescribed for you by your doctor.

Tyrosine is often sold as an herbal supplement. There are no regulated manufacturing standards in place for many herbal compounds and some marketed supplements have been found to be contaminated with toxic metals or other drugs. Herbal/health supplements should be purchased from a reliable source to minimize the risk of contamination.

Tyrosine may also be used for purposes not listed in this product guide.

Follow all directions on the product label and package. Tell each of your healthcare providers about all your medical conditions, allergies, and all medicines you use.

When considering the use of herbal supplements, seek the advice of your doctor. You may also consider consulting a practitioner who is trained in the use of herbal/health supplements.

If you choose to use tyrosine, use it as directed on the package or as directed by your doctor, pharmacist, or other healthcare provider. Do not use more of this product than is recommended on the label.

Your dose of tyrosine will depend on the amount of protein you consume in your diet. Follow your doctor's dosing instructions very carefully.

Tyrosine is only part of a complete program of treatment that may also include a special diet. Follow the diet plan created for you by your doctor or nutrition counselor. Get familiar with the list of foods you must eat or avoid to help control your condition.

Call your doctor if the condition you are treating with tyrosine does not improve, or if it gets worse while using this product.

Store at room temperature away from moisture and heat.

Before using tyrosine, talk to your healthcare provider. You may not be able to use tyrosine if you have certain medical conditions, especially:

• overactive thyroid; or

• Graves disease.

It is not known whether tyrosine will harm an unborn baby. Do not use this product without medical advice if you are pregnant.

It is not known whether tyrosine passes into breast milk or if it could harm a nursing baby. Do not use this product without medical advice if you are breast-feeding a baby.

Do not give any herbal/health supplement to a child without medical advice.

Skip the missed dose if it is almost time for your next scheduled dose. Do not use extra tyrosine to make up the missed dose.

Seek emergency medical attention or call the Poison Help line at 1-800-222-1222.

Follow your healthcare provider's instructions about any restrictions on food, beverages, or activity.

Get emergency medical help if you have signs of an allergic reaction: hives; difficult breathing; swelling of your face, lips, tongue, or throat.

Although not all side effects are known, tyrosine is thought to be likely safe in most adults when taken for up to 3 months.

Common side effects of tyrosine may include:

• nausea, heartburn;

• headache;

• joint pain; or

• feeling tired.

This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.

Do not take tyrosine without medical advice if you are using any of the following medications:

• levodopa; or

• thyroid replacement (Synthroid, Levothroid, and others).

This list is not complete. Other drugs may interact with tyrosine, including prescription and over-the-counter medicines, vitamins, and herbal products. Not all possible interactions are listed in this product guide.