Skip to main content


Medically reviewed by Last updated on Dec 1, 2021.

What are other common names?

  • L-Triptofano
  • L-Trypt
  • L-Tryptophane
  • Tryptofan
  • Tryptophan

What is this product used for?

L-Tryptophan is also known as tryptophan. No information from medical studies supports the use of this product for any health problem.

What are the precautions when taking this product?

  • Always check with your doctor before you use a natural product. Some products may not mix well with drugs or other natural products.

  • Be sure to tell your doctor that you take this product if you are scheduled for surgery or tests.

  • Be sure to tell your doctor if you are pregnant, plan on getting pregnant, or are breastfeeding. You will need to talk about the benefits and risks of using this natural product.

  • Avoid beer, wine, and mixed drinks (alcohol) while taking this product.

  • This product may cause you to be sleepy. Take extra care driving and doing tasks that you need to be alert for.

  • Take extra care if you are taking drugs that make you drowsy or help you sleep. These are drugs like lorazepam, phenobarbital, zolpidem, or diphenhydramine.

  • This product is used by your body to make serotonin. Do not use this product if you are taking other products that also raise serotonin in your body, such as some cough medicines, SSRIs, or MAO inhibitors. These are products like St John’s wort, dextromethorphan, fluoxetine, citalopram, isocarboxazid, phenelzine, and tranylcypromine.

  • Take extra care and check with your doctor if you have:

    • Mental problems like low mood

    • Kidney problems

    • Liver problems

    • Problems with your white blood cells

What should I watch for?

  • Upset stomach

  • Burping and gas

  • Dizziness

  • Dry mouth

When do I need to call the doctor?

  • Signs of a very bad reaction. These include wheezing; chest tightness; fever; itching; bad cough; blue skin color; seizures; or swelling of face, lips, tongue, or throat. Go to the ER right away.

  • Signs of liver problems. These include upset stomach or throwing up, belly pain, feeling tired, dark urine, yellow skin or eyes, not hungry.

  • Signs of too much serotonin in your body: Irritability, restlessness, confusion, fast heartbeat, twitching, very bad sweating, very high fever, seizures, or uneven heartbeat.

  • Hard areas on skin

  • Very bad tiredness

  • Very bad muscle pain

  • Very bad loose stools, belly pain, or throwing up

  • Very bad headache

Last Reviewed Date


Consumer information use

This generalized information is a limited summary of diagnosis, treatment, and/or medication information. It is not meant to be comprehensive and should be used as a tool to help the user understand and/or assess potential diagnostic and treatment options. It does NOT include all information about conditions, treatments, medications, side effects, or risks that may apply to a specific patient. It is not intended to be medical advice or a substitute for the medical advice, diagnosis, or treatment of a health care provider based on the health care provider's examination and assessment of a patient’s specific and unique circumstances. Patients must speak with a health care provider for complete information about their health, medical questions, and treatment options, including any risks or benefits regarding use of medications. This information does not endorse any treatments or medications as safe, effective, or approved for treating a specific patient. UpToDate, Inc. and its affiliates disclaim any warranty or liability relating to this information or the use thereof. The use of this information is governed by the Terms of Use, available at


Copyright © 2022 UpToDate, Inc. and its affiliates and/or licensors. All rights reserved.

Further information

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.