L-tryptophan

What is the most important information I should know about L-tryptophan?

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.

What is L-tryptophan?

L-tryptophan is an amino acid that is made from plant or animal sources. L-tryptophan is known as an "essential" amino acid because the body does not produce it. L-tryptophan is important to the functions of many organs in the body. When you consume L-tryptophan, your body absorbs it and changes it to eventually become a hormone called serotonin. Serotonin transmits signals between your nerve cells and also narrows (constricts) blood vessels. The amount of serotonin in the brain can affect mood.

L-tryptophan has been used in alternative medicine as a possibly effective aid in treating symptoms of premenstrual dysphoric disorder syndrome (such as mood swings and irritability), and to help people quit smoking.

L-tryptophan has also been used to treat facial pain, to relieve bruxism (tooth grinding), and to improve athletic performance. However, research has shown that L-tryptophan may not be effective in treating these conditions.

Other uses not proven with research include treating sleep problems (insomnia), anxiety, depression, and attention deficit hyperactivty disorder (ADHD).

L-tryptophan 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.

It may be dangerous to purchase L-tryptophan on the Internet or from vendors outside of the United States. The manufacture, sale, and distribution of L-tryptophan outside of the U.S. does not comply with the regulations of the Food and Drug Administration (FDA) for the safe use of this medication.

L-tryptophan may also be used for purposes not listed in this product guide.

What should I discuss with my health care provider before taking L-tryptophan?

Ask a doctor, pharmacist, or other healthcare provider if it is safe for you to use this product if you have:

• liver disease;
• kidney disease;
• eosinophilia (high levels of a certain type of white blood cells); or
• a muscle disorder (such as fibromyalgia).

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

How should I take L-tryptophan?

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 L-tryptophan, 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.

What happens if I miss a dose?

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

What happens if I overdose?

What should I avoid while taking L-tryptophan?

Avoid using L-tryptophan together with other herbal/health supplements that can also cause drowsiness, including 5-hydroxytryptophan (5-HTP), calamus, California poppy, catnip, hops, Jamaican dogwood, kava, St. John's wort, skullcap, valerian, or yerba mansa.

Avoid using L-tryptophan together with other herbal/health supplements that can raise your serotonin levels. This includes 5-HTP, Hawaiian baby woodrose, and S-adenosylmethionine (SAMe).

What are the possible side effects of L-tryptophan?

Although not all side effects are known, L-tryptophan is thought to be possibly unsafe. Be sure to use this product only if you have obtained it from a safe and reputable source.

• unusual tiredness;
• severe muscle pain (most often in the shoulders, back, or legs);
• weakness, numbness, tingling, or burning pain (especially at night);
• tremors or twitching muscle movements;
• swelling in any part of your body;
• skin changes (dryness, yellowing, hardening, rash, hair loss);
• breathing difficulty; or
• uneven heartbeat.

Common side effects may include:

• feeling drowsy or light-headed;
• dry mouth, heartburn, burping, gas;
• stomach pain, nausea, vomiting, diarrhea;
• weakness, lack of coordination;
• blurred vision;
• headache; or
• sexual problems.

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.

What other drugs will affect L-tryptophan?

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

• tramadol (Ultram, Ultracet);
• a cough medicine that contains dextromethorphan (Delsym, Robitussin DM, and others);
• an MAO inhibitor such as isocarboxazid, linezolid, methylene blue injection, phenelzine, rasagiline, selegiline, tranylcypromine, and others;
• medicine to treat mental illness such as chlorpromazine (Thorazine), fluphenazine (Prolixin), thioridazine (Mellaril), and others;
• a narcotic medicine such as meperidine (Demerol) or pentazocine (Talwin); or
• a sedative such as diazepam (Valium), clonazepam (Klonopin), lorazepam (Ativan), and others.

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

Where can I get more information?

Consult with a licensed healthcare professional before using any herbal/health supplement. Whether you are treated by a medical doctor or a practitioner trained in the use of natural medicines/supplements, make sure all your healthcare providers know about all of your medical conditions and treatments.