Reviews and Information for Tryptophan (L-Tryptophan)
L-tryptophan and 5-Hydroxy-L-tryptophan (5-HTP)
Learn how to find the best L-Tryptophan and 5-Hydroxytryptophan (5-HTP) supplements, evidence for using L-tryptophan or 5-HTP for sleep, depression, migraine, and more. Plus, dosage, safety, side effects and potential drug interactions. Find out which L-Tryptophan and 5-Hydroxytryptophan (5-HTP) supplements passed our tests.
L-tryptophan and 5-Hydroxy-L-tryptophan (5-HTP) Review
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Clinical Update
11/20/2011
L-Tryptophan -- Still a Problem?
A woman in Illinois taking L-tryptophan for insomnia developed the same serious problems that resulted in L-tryptophan being temporarily removed from the market several years ago. Is L-tryptophan any safer now than it was before? For more information, see the update to the L-Tryptophan and 5-HTP Review Article.
Clinical Update
8/04/2013
5-HTP Concern
Three cases of eosinophilia-myalgia syndrome (EMS) have been reported among people taking 5-HTP, a compound related to L-tryptophan. EMS is a debilitating immune condition which has occurred in people taking L-tryptophan, but there were no previous reports of it being caused by 5-HTP. Get the details in the the updated review article on L-Tryptophan and 5-HTP >>
Product Review
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CL Answer
Which vitamins and supplements should be stopped before getting blood work, laboratory tests, or medical imaging?
Find out which vitamins and supplements can interfere with blood, urine or stool tests, and imaginging tests, like bone scans and MRIs. Learn how B vitamins such as biotin, niacin and riboflavin, as well as calcium supplements, St. John’s wort, vitamin C, and others supplements can affect test results, as well as common foods that may interfere with tests.
Clinical Update
8/24/2021
Parkinson's Disease: 5-HTP for Sleep?
Can supplementation with 5-HTP reduce sleep disturbances in people with Parkinson's disease? See what a recent study found in the What It Does section of our L-Tryptophan and 5-HTP Supplements Review.
Also see our answer to the question: Do supplements help with Parkinson's disease treatment or prevention?
Clinical Update
1/19/2019
Dog Overdoses on Supplement
Be sure to keep your supplements away from pets -- especially if they taste sweet. A dog overdosed on its owner's fast-dissolving tablets, putting it in a coma, according to a recent report. For details, see the Concerns and Cautions section of the L-tryptophan and 5-HTP Supplements Review.
Clinical Update
11/08/2022
5-HTP for Sleep?
A CL Member asked how to use 5-HTP to improve sleep. Find out what research suggests in the 5-HTP section of our 5-HTP and L-Tryptophan and Supplements Review.
Also see our CL Answer about supplements and lifestyle modifications for insomnia.
CL Answer
Which supplements and lifestyle changes improve sleep, and which cause insomnia?
Find out which vitamins may help you sleep and learn if any vitamins or supplements can cause insomnia.
Product Review
Olive Leaf Extract Supplements Review
Learn What Olive Leaf Does and the Best Brands
News Release
July 31, 2018
Best L-Tryptophan and 5-HTP Supplements Identified by ConsumerLab -- ConsumerLab Tests Strength and Purity of Supplements for Sleep and Mood
White Plains, New York, July 31, 2018 — L-tryptophan supplements are often promoted to improve sleep and 5-HTP supplements to help with depression.
Product Review
Lion's Mane and Chaga Supplements Review
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CL Answer
Which supplements may benefit people with essential tremor, and which should be avoided?
Learn about supplements used for treating essential tremor, including caprylic acid (also called octanoic acid), thiamin (vitamin B1), cannabidiol (CBD), GABA (gamma-aminobutyric acid), and branched-chain amino acids. Find out which work and which don't. Also find out which supplements and food may make essential tremors worse.
CL Answer
Does methylene blue increase energy, slow aging, or improve memory?
Methylene blue is promoted for increasing energy, slowing aging, and improving memory. Find out if there is evidence for this, plus safety and side effects.
CL Answer
Do supplements help with Parkinson’s disease treatment or prevention?
Learn what has been shown with vitamins D and E, niacin, CoQ10, melatonin, creatine, SAMe, NAC, valerian, CoQ10, and CBD, as well as with coffee and the Mediterranean and MIND diets for treating and/or preventing Parkinson's disease.
Recalls & Warnings
February 22, 2021
FDA Warns Seller of Melatonin & Other Sleep Supplements
On February 18, 2021, the FDA issued a warning letter to SANA Group LLC following a review of the company's website, which found statements made about the company's products Sleep Sana Sleep Drops and Sleep Shots to be drug claims.
CL Answer
What are the best supplements for depression and anxiety?
Best natural supplements for depression and anxiety, including the evidence for fish oil, vitamin D, probiotics, and herbal supplements for depression such as curcumin (from turmeric) and saffron.
CL Answer
Does ergothioneine help prevent age-related problems such as impaired cognition, Alzheimer’s disease, Parkinson’s disease or cataract, and is it safe?
Learn about ergothioneine and its potential use for cognitive impairment, dementia, Alzheimer's disease, Parkinson's disease, cataract, or kidney disease, as well as its safety and cost of supplements containing this ingredient.
Recalls & Warnings
December 01, 2018
Seller of 5-HTP, Potassium & More Warned for Manufacturing Violations
On September 7, 2018, the FDA issued a warning letter to The Delano Company, Inc.
Recalls & Warnings
December 21, 2016
Seller of 5-HTP, Chromium, Curcumin and More Warned for Drug Claims
On December 1, 2016, the FDA issued a warning letter to Aurora Health and Nutrition following a review of the company's website, which found statements made about its products, 5-HTP, Alpha Lipoic Acid, the Argentyn 23 product line, Artecin 90 Vegetarian Capsules, ...
Recalls & Warnings
July 27, 2012
Prescription and Street Drug Alternatives Found in Male Enhancement, Mood, and Sleep Supplements
On July 10, 2012, the FDA issued a warning letter to Evol Nutrition Associates, Inc. subsequent to a 2011 inspection which found a number of the company's products contained prescription and investigational drugs and were misbranded.
