What is L-tryptophan?
L-tryptophan is an amino acid that is made from plant or animal sources.
L-tryptophan has been used in alternative medicine as an aid to treat sleep problems (insomnia),
anxiety, depression, premenstrual syndrome, attention deficit disorder, and for smoking cessation and
other conditions.
Not all uses for l-tryptophan have been approved by the FDA. L-tryptophan should not be
substituted for medications prescribed for you by your doctor.
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 is dangerous to try and purchase l-tryptophan on the Internet or from vendors outside of the
United States. The 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 other purposes not listed in this product guide.
What should I discuss with my healthcare provider before taking L-tryptophan?
Do not use this product if you are allergic to l-tryptophan.
Before using l-tryptophan, talk to your doctor, pharmacist, herbalist, or other healthcare
provider. You may not be able to use l-tryptophan if you have certain medical conditions.
If you have certain conditions, you may need a dose adjustment or special tests to safely use
this product. Before using l-tryptophan, talk to your doctor, pharmacist, herbalist, or other healthcare
provider if you have:
It is not known whether l-tryptophan is harmful to an unborn baby. Do
not use this product without talking to a healthcare provider if you are pregnant or plan to become
pregnant during treatment.
L-tryptophan may pass into breast milk and may harm a nursing baby. Ask your healthcare
provider before using l-tryptophan if you are breast-feeding a baby.
Do not give any herbal/health supplement to a child without the advice of a doctor.
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 take 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 l-tryptophan than is
recommended on the label.
Store L-tryptophan at room temperature away from moisture and heat.
What happens if I miss a dose of L-tryptophan?
Consult your doctor, pharmacist, herbalist, or other healthcare provider for instructions if you
miss a dose.
Where can I get more information about L-tryptophan?
Your pharmacist has information about L-tryptophan written for health professionals that you may read.
What are the possible side effects of L-tryptophan?
Get emergency medical help if you have any of these
signs of an allergic
reaction:
hives; difficulty breathing; swelling of your face, lips, tongue, or throat.
In 1989, a life-threatening condition called eosinophilia-myalgia syndrome (EMS) occurred in
many people using L-tryptophan and some died from the condition. All of these people had taken
L-tryptophan distributed by a company in Japan. This L-tryptophan was found to contain trace levels
of impure ingredients. Since that time, the FDA has limited the availability of L-tryptophan in the U.S.
However, the increased use of the Internet has made many dietary supplements available from
non-U.S. sources.
There have been no published cases of EMS within the last several years, but you should
be aware of the symptoms. Call your doctor at once if you have any of the following:
-
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);
-
breathing difficulty; or
-
uneven heartbeat.
Less serious side effects may include:
-
dry mouth, heartburn, burping, gas;
-
nausea, vomiting, diarrhea;
-
feeling drowsy or light-headed;
-
blurred vision;
-
weakness, lack of coordination;
-
headache; or
-
lost appetite.
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 is the most important information I should know about L-tryptophan?
Not all uses for l-tryptophan have been approved by the FDA. L-tryptophan should not be
substituted for medications prescribed for you by your doctor.
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.
Use l-tryptophan as directed on the label, or as your healthcare provider has prescribed. Do
not use this product in larger amounts or for longer than recommended.
It is dangerous to try and purchase l-tryptophan on the Internet or from vendors outside of the
United States. The 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.
In 1989, a life-threatening condition called eosinophilia-myalgia syndrome (EMS) occurred in
many people using L-tryptophan and some died from the condition. All of these people had taken
L-tryptophan distributed by a company in Japan. This L-tryptophan was found to contain trace levels
of impure ingredients. Since that time, the FDA has limited the availability of L-tryptophan in the U.S.
However, the increased use of the Internet has made many dietary supplements available from
non-U.S. sources.
There have been no published cases of EMS within the last several years, but you should
be aware of the symptoms. Stop using L-tryptophan and call your doctor or care practitioner at once if
you have any of these signs of EMS: 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); breathing
difficulty; uneven heartbeat.
What should I avoid while taking L-tryptophan?
L-tryptophan can cause side effects that may impair your thinking or reactions. Be careful if
you drive or do anything that requires you to be awake and alert.
Avoid using other dietary or herbal supplements to treat the same condition for which you
are using L-tryptophan.
What other drugs will affect L-tryptophan?
L-tryptophan may interact with other medicines. Before taking L-tryptophan, tell your
doctor or care practitioner if you are also using:
-
medicine for depression such as St. John's wort, citalopram
(Celexa), escitalopram (Lexapro), fluoxetine (Prozac), paroxetine (Paxil), sertraline (Zoloft),
amitriptyline (Elavil), imipramine (Tofranil), venlafaxine (Effexor), and others;
-
a monoamine oxidase inhibitor (MAOI) such as
tranylcypromine (Nardil), phenelzine (Parnate), selegiline (Eldepryl), or isocarboxazid
(Marplan);
-
a sedative or tranquilizer such as diazepam (Valium),
lorazepam (Ativan), clonazepam (Klonopin) and others;
-
a phenothiazine drug such as chlorpromazine, (Thorazine),
prochlorperazine (Compazine) and others; or
-
drugs that make you sleepy (such as alcohol, cold medicine,
pain medication, muscle relaxants, and medicine for depression or anxiety).
This list is not complete and there may be other drugs that can interact with
L-tryptophan. Tell your doctor or care practitioner about all the prescription and over-the-counter
medications you use. This includes vitamins, minerals, herbal products, and drugs prescribed by other
doctors. Do not start using a new medication without telling your doctor or care practitioner.
What happens if I have an overdose of L-tryptophan?
