L-Triptofano, L-Trypt, L-2-amino-3-(indole-3-yl) propionic acid, L-Tryptophane, Tryptophan.
L-tryptophan is an amino acid, a protein building block that can be found in many plant and animal proteins. L-tryptophan is called an “essential” amino acid because the body can't make it. It must be acquired from food.
L-tryptophan is used for insomnia, sleep apnea, depression, anxiety, facial pain, a severe form of premenstrual syndrome called premenstrual dysphoric disorder (PMDD), smoking cessation, grinding teeth during sleep (bruxism), attention deficit-hyperactivity disorder (ADHD), Tourette's syndrome, and to improve athletic performance.
How does it work?
L-tryptophan is naturally found in animal and plant proteins. L-tryptophan is considered an essential amino acid because our bodies can't make it. It is important for the development and functioning of many organs in the body. After absorbing L-tryptophan from food, our bodies convert it to 5-HTP (5-hyrdoxytryptophan), and then to serotonin. Serotonin is a hormone that transmits signals between nerve cells. It also causes blood vessels to narrow. Changes in the level of serotonin in the brain can alter mood.
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How to Quit Smoking: 13 Tips to End Addiction See SlideshowPossibly Effective for...
- Treating premenstrual dysphoric disorder (PMDD). Taking 6 grams of L-tryptophan per day seems to decrease mood swings, tension, and irritability in women with PMDD.
- Smoking cessation (helping people quit smoking). Taking L-tryptophan seems to improve the effectiveness of conventional treatment for smoking cessation.
Possibly Ineffective for...
- Treating teeth grinding (bruxism).
- Treating facial pain.
- Improving athletic ability.
Insufficient Evidence to Rate Effectiveness for...
- Depression. Developing research suggests that L-tryptophan might improve the effectiveness of common medications for depression.
- Seasonal affective disorder (SAD). Early research suggests L-tryptophan might be helpful in SAD.
- Attention deficit-hyperactivity disorder (ADHD). There is some evidence that L-tryptophan levels are lower in children with ADHD; however, taking L-tryptophan supplements does not appear to improve ADHD symptoms.
- Treating sleep disorders. Taking L-tryptophan might decrease the amount of time it takes to fall asleep and improve mood in healthy people with sleep problems. There is also some evidence that taking L-tryptophan might decrease episodes in some people who periodically stop breathing during sleep (sleep apnea).
- Anxiety.
- Other conditions.
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).
L-tryptophan is POSSIBLY UNSAFE when taken by mouth. It has been linked to over 1500 reports of eosinophilia-myalgia syndrome (EMS) and 37 deaths. EMS is a neurological condition with symptoms that include fatigue; intense muscle pain; nerve pain; skin changes; baldness; rash; and pain and swelling affecting the joints, connective tissue, lungs, heart, and liver. Symptoms tend to improve over time, but some people may still experience symptoms up to 2 years after they develop EMS. Some people report that their symptoms have never gone away completely.
In 1990, L-tryptophan was recalled from the market due to these safety concerns. After the limitation of L-tryptophan products, the number of EMS cases dropped sharply. The exact cause of EMS in patients taking L-tryptophan is unknown, but some evidence suggests it may be due to contaminated L-tryptophan products. About 95% of all EMS cases were traced to L-tryptophan produced by a single manufacturer in Japan. Currently, under the Dietary Supplement Health and Education Act (DSHEA) of 1994, L-tryptophan is available and marketed as a dietary supplement.
L-tryptophan can cause some side effects such as heartburn, stomach pain, belching and gas, nausea, vomiting, diarrhea, and loss of appetite. It can also cause headache, lightheadedness, drowsiness, dry mouth, visual blurring, muscle weakness, and sexual problems.
QUESTION
What is the average weight gain for those who quit smoking? See AnswerA white blood cell disorder called eosinophilia: L-tryptophan might make this condition worse. L-tryptophan has been associated with the development of eosinophilia-myalgia syndrome (EMS).
Liver or kidney disease: L-tryptophan might make these conditions worse since it has been associated with the development of eosinophilia-myalgia syndrome (EMS).
Sedative medications (CNS depressants)Interaction Rating: Major Do not take this combination.
L-tryptophan might cause sleepiness and drowsiness. Medications that cause sleepiness are called sedatives. Taking L-tryptophan along with sedative medications might cause too much sleepiness.
Some sedative medications include clonazepam (Klonopin), lorazepam (Ativan), phenobarbital (Donnatal), zolpidem (Ambien), and others.
Dextromethorphan (Robitussin DM, and others)Interaction Rating: Moderate Be cautious with this combination.Talk with your health provider.
L-tryptophan can affect a brain chemical called serotonin. Dextromethorphan (Robitussin DM, others) can also affect serotonin. Taking L-tryptophan along with dextromethorphan (Robitussin DM, others) might cause there to be too much serotonin in the brain and serious side effects including heart problems, shivering and anxiety could occur. Do not take L-tryptophan if you are taking dextromethorphan (Robitussin DM, others).
Medications for depression (Antidepressant drugs)Interaction Rating: Moderate Be cautious with this combination.Talk with your health provider.
L-tryptophan increases a brain chemical called serotonin. Some medications for depression also increase the brain chemical serotonin. Taking L-tryptophan along with these medications for depression might increase serotonin too much and cause serious side effects including heart problems, shivering, and anxiety. Do not take L-tryptophan if you are taking medications for depression.
Some of these medications for depression include fluoxetine (Prozac), paroxetine (Paxil), sertraline (Zoloft), amitriptyline (Elavil), clomipramine (Anafranil), imipramine (Tofranil), and others.
Medications for depression (MAOIs)Interaction Rating: Moderate Be cautious with this combination.Talk with your health provider.
L-tryptophan increases a chemical in the brain. This chemical is called serotonin. Some medications used for depression also increase serotonin. Taking L-tryptophan with these medications used for depression might cause there to be too much serotonin. This could cause serious side effects including heart problems, shivering, and anxiety.
Some of these medications used for depression include phenelzine (Nardil), tranylcypromine (Parnate), and others.
Meperidine (Demerol)Interaction Rating: Moderate Be cautious with this combination.Talk with your health provider.
L-tryptophan increases a chemical in the brain called serotonin. Meperidine (Demerol) can also increase serotonin in the brain. Taking L-tryptophan along with meperidine (Demerol) might cause too much serotonin in the brain and serious side effects including heart problems, shivering, and anxiety.
Pentazocine (Talwin)Interaction Rating: Moderate Be cautious with this combination.Talk with your health provider.
L-tryptophan increases a brain chemical called serotonin. Pentazocine (Talwin) also increases serotonin. Taking L-tryptophan along with pentazocine (Talwin) might cause serious side effects including heart problems, shivering, and anxiety. Do not take L-tryptophan if you are taking pentazocine (Talwin).
PhenothiazinesInteraction Rating: Moderate Be cautious with this combination.Talk with your health provider.
Taking L-tryptophan with phenothiazines can cause serious side effects including movement disorders.
Some phenothiazines include chlorpromazine (Thorazine), fluphenazine (Prolixin), trifluoperazine (Stelazine), thioridazine (Mellaril), and others.
Sedative medications (Benzodiazepines)Interaction Rating: Moderate Be cautious with this combination.Talk with your health provider.
Sedative medications can affect the nervous system. L-tryptophan can also affect the nervous system. Taking L-tryptophan along with sedative medications can cause serious side effects. Do not take L-tryptophan if you are taking sedative medications.
Some of these sedative medications include clonazepam (Klonopin), diazepam (Valium), lorazepam (Ativan), and others.
Tramadol (Ultram)Interaction Rating: Moderate Be cautious with this combination.Talk with your health provider.
Tramadol (Ultram) can affect a chemical in the brain called serotonin. L-tryptophan can also affect serotonin. Taking L-tryptophan along with tramadol (Ultram) might cause too much serotonin in the brain and side effects including confusion, shivering, and stiff muscles could result.
The appropriate dose of L-tryptophan depends on several factors such as the user's age, health, and several other conditions. At this time, there is not enough scientific information to determine an appropriate range of doses for L-tryptophan. Keep in mind that natural products are not always necessarily safe and dosages can be important. Be sure to follow relevant directions on product labels and consult your pharmacist or physician or other healthcare professional before using.
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You are encouraged to report negative side effects of prescription drugs to the FDA. Visit the FDA MedWatch website or call 1-800-FDA-1088.
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Bell C, Abrams J, Nutt D. Tryptophan depletion and its implications for psychiatry. Br J Psychiatry 2001;178:399-405.. View abstract.
Bohme A, Wolter M, Hoelzer D. L-tryptophan-related eosinophilia-myalgia syndrome possibly associated with a chronic B-lymphocytic leukemia. Ann Hematol 1998;77:235-8.
Bornstein RA, Baker GB, Carroll A, et al. Plasma amino acids in attention deficit disorder. Psychiatry Res 1990;33:301-6.. View abstract.
Bowen DJ, Spring B, Fox E. Tryptophan and high-carbohydrate diets as adjuncts to smoking cessation therapy. J Behav Med 1991;14:97-110. View abstract.
Bryant SM, Kolodchak J. Serotonin syndrome resulting from an herbal detox cocktail. Am J Emerg Med 2004;22:625-6. View abstract.
Carr L, Ruther E, Berg PA, Lehnert H. Eosinophilia-myalgia syndrome in Germany: an epidemiologic review. Mayo Clin Proc 1994;69:620-5. View abstract.
Delgado PL, Price LH, Miller HL. Serotonin and the neurobiology of depression. Effects of tryptophan depletion in drug-free depressed patients. Arch Gen Psychiatr 1994;51:865-74. View abstract.
Devoe LD, Castillo RA, Searle NS. Maternal dietary substrates and human fetal biophysical activity. The effects of tryptophan and glucose on fetal breathing movements. Am J Obstet Gynecol 1986;155:135-9. View abstract.
Etzel KR, Stockstill JW, Rugh JD. Tryptophan supplementation for nocturnal bruxism: report of negative results. J Craniomandib Disord 1991;5:115-20. View abstract.
Ghadirian AM, Murphy BE, Gendron MJ. Efficacy of light versus tryptophan therapy in seasonal affective disorder. J Affect Disord 1998;50:23-7. View abstract.
Ghose K. l-Tryptophan in hyperactive child syndrome associated with epilepsy: a controlled study. Neuropsychobiology 1983;10:111-4. View abstract.
Greenberg AS, Takagi H, Hill RH, et al. Delayed onset of skin fibrosis after the ingestion of eosinophilia-myalgia syndrome-associated L-tryptophan. J Am Acad Dermatol 1996;35:264-6. View abstract.
Hartmann E, Spinweber CL. Sleep induced by L-tryptophan. Effect of dosages within the normal dietary intake. J Nerv Ment Dis 1979;167:497-9. View abstract.
Hatch DL, Goldman LR. Reduced severity of eosinophilia-myalgia syndrome associated with consumption of vitamin-containing supplements before illness. Arch Intern Med 1993;153: 2368-73. View abstract.
Horwitz RI, Daniels SR. Bias or biology: evaluating the epidemiologic studies of L-tryptophan and the eosinophilia-myalgia syndrome. J Rheumatol Suppl 1996;46:60-72. View abstract.
Hudson JI, Pope HG, Daniels SR, Horwitz RI. Eosinophilia-myalgia syndrome or fibromyalgia with eosinophilia? JAMA 1993;269:3108-9. View abstract.
Kilbourne EM, Philen RM, Kamb ML, Falk H. Tryptophan produced by Showa Denko and epidemic eosinophilia-myalgia syndrome. J Rheumatol Suppl 1996;46:81-8. View abstract.
Klein R, Berg PA. A comparative study on antibodies to nucleoli and 5-hydroxytryptamine in patients with fibromyalgia syndrome and tryptophan-induced eosinophilia-myalgia syndrome. Clin Investig 1994;72:541-9.. View abstract.
Korner E, Bertha G, Flooh E, et al. Sleep-inducing effect of L-tryptophane. Eur Neurol 1986;25 Suppl 2:75-81. View abstract.
Lieberman HR, Corkin S, Spring BJ. The effects of dietary neurotransmitter precursors on human behavior. Am J Clin Nutr 1985;42:366-70. View abstract.
Mayeno AN, Gleich GJ. The eosinophilia-myalgia syndrome: lessons from Germany. Mayo Clin Proc 1994;69:702-4. View abstract.
Messiha FS. Fluoxetine: adverse effects and drug-drug interactions. J Toxicol Clin Toxicol 1993;31:603-30. View abstract.
Murphy FC, Smith KA, Cowen PJ, et al. The effects of tryptophan depletion on cognitive and affective processing in healthy volunteers. Psychopharmacology (Berl) 2002;163:42-53.. View abstract.
Nardini M, De Stefano R, Iannuccelli M, et al. Treatment of depression with L-5-hydroxytryptophan combined with chlorimipramine, a double-blind study. Int J Clin Pharmacol Res 1983;3:239-50. View abstract.
Philen RM, Hill RH, Flanders WD, et al. Tryptophan contaminants associated with eosinophilia-myalgia syndrome. Am J Epidemiol 1993;138:154-9. View abstract.
Priori R, Conti F, Luan FL, et al. Chronic fatigue: a peculiar evolution of eosinophilia myalgia syndrome following treatment with L-tryptophan in four Italian adolescents. Eur J Pediatr 1994;153:344-6.. View abstract.
Schmidt HS. L-tryptophan in the treatment of impaired respiration in sleep. Bull Eur Physiopathol Respir 1983;19:625-9. View abstract.
Seltzer S, Dewart D, Pollack R, Jackson E. The effects of dietary tryptophan on chronic maxillofacial pain and experimental pain tolerance. J Psychiatr Res 1982-83;17:181-6. View abstract.
Shapiro S. Epidemiologic studies of the association of L-tryptophan with the eosinophilia-myalgia syndrome: a critique. J Rheumatol Suppl 1996;46:44-58. View abstract.
Shapiro S. L-tryptophan and eosinophilia-myalgia syndrome. Lancet 1994;344:817-9.View abstract.
Sharma RP, Shapiro LE, Kamath SK. Acute dietary tryptophan depletion: effects on schizophrenic positive and negative symptoms. Neuropsychobiol 1997;35:5-10. View abstract.
Shaw K, Turner J, Del Mar C. Tryptophan and 5-hydroxytryptophan for depression. Cochrane Database Syst Rev 2002;(1):CD003198. View abstract.
Simat TJ, Kleeberg KK, Muller B, Sierts A. Synthesis, formation, and occurrence of contaminants in biotechnologically manufactured L-tryptophan. Adv Exp Med Biol 1999;467:469-80.. View abstract.
Singhal AB, Caviness VS, Begleiter AF, et al. Cerebral vasoconstriction and stroke after use of serotonergic drugs. Neurology 2002;58:130-3. View abstract.
Smith KA, Fairburn CG, Cowen PJ. Symptomatic relapse in bulimia nervosa following acute tryptophan depletion. Arch Gen Psychiatr 1999;56:171-6. View abstract.
Steinberg S, Annable L, Young SN, Liyanage N. A placebo-controlled study of the effects of L-tryptophan in patients with premenstrual dysphoria. Adv Exp Med Biol 1999;467:85-8. View abstract.
Stockstill JW, McCall D Jr., Gross AJ. The effect of L-tryptophan supplementation and dietary instruction on chronic myofascial pain. J Am Dent Assoc 1989;118:457-60. View abstract.
Sullivan EA, Kamb ML, Jones JL, et al. The natural history of eosinophilia-myalgia syndrome in a tryptophan-exposed cohort in South Carolina. Arch Intern Med 1996;156:973-9. View abstract.
U. S. Food and Drug Administration, Center for Food Safety and Applied Nutrition, Office of Nutritional Products, Labeling, and Dietary Supplements. Information Paper on L-Tryptophan and 5-hydroxy-L-tryptophan, February 2001.
van Hall G, Raaymakers JS, Saris WH. Ingestion of branched-chain amino acids and tryptophan during sustained exercise in man: failure to affect performance. J Physiol (Lond) 1995;486:789-94. View abstract.
van Praag HM. Management of depression with serotonin precursors. Biol Psychiatry 1981;16:291-310.. View abstract.
Walinder J, Skott A, Carlsson A, et al. Potentiation of the antidepressant action of clomipramine by tryptophan. Arch Gen Psychiatry 1976;33:1384-89.. View abstract.