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L-tryptophan and 5-HTP: Some Detective Work

Time and again I read about the positive impact of L-tryptophan and 5-HTP upon mood, anxiety, sleep, and more. And, of course, supplements abound. So what do you say we take an objective look.

L-tryptophan is one of eight essential amino acids for humans. What that means is we can’t synthesize it internally, so we have to obtain it through diet. L-tryptophan is the precursor of several compounds, one of which is the ever-popular neurotransmitter, serotonin.

Serotonin’s role in mood and anxiety is well known. But you may not have been aware of the fact that serotonin is the precursor of melatonin. And since melatonin is a major player in sleep, so then are serotonin and L-tryptophan.

Common dietary sources of L-tryptophan are chocolate, milk, yogurt, red meat, fish, poultry, sunflower seeds, peanuts, and eggs. And while we’re at it, let’s address a Thanksgiving/Christmas Day myth. Turkey has no more L-tryptophan than any other hunk of poultry. So if you’re looking for the cause of those post-feast sleepies, you’d be better served by taking a peak at the carbohydrate content of the other dishes.

For years, L-tryptophan has been available as a dietary supplement. In addition to being used as a mood enhancer and sleep aid, it’s shown promise in the treatment of specific situations such as premenstrual dysphoric disorder (PMDD) and seasonal affective disorder (SAD). It’s also shown promise as an independent antidepressant, as well as a supplement to an existing antidepressant regimen.

Of note, there was a large L-tryptophan-related outbreak of something known as eosinophilia-myalgia syndrome (EMS) in 1989. The final score was 1,500 cases of permanent disability and at least 38 deaths. How did that happen? Well, several theories have been offered. The one that seems to stick is the outbreak being traced to L-tryptophan supplied by a Japanese supplement manufacturer. It seems genetic engineering used in production may have been the culprit.

The sale of most L-tryptophan was banned in the United States in 1991. And even after it was known that a contaminated batch caused the outbreak, and the manufacturing process had been fixed, the FDA still maintained L-tryptophan was unsafe. Finally, in 2001, the FDA loosened up, but still issued a cautionary statement.

Since 2002, L-tryptophan has been sold in the United States in its original form.

5-Hydroxytryptophan (5-HTP) is a naturally-occurring amino acid, and is a catalyst in the synthesis of serotonin and melatonin from L-tryptophan. Bottom-line: it increases the production of serotonin.

5-HTP is primarly used as a mood enhancer and sleep aid. It’s also been reported to be an effective appetite suppressant. In addition, it’s shown promise in the treatment of fibromyalgia, anxiety, and binge-eating associated with obesity.

Like L-tryptophan, 5-HTP is sold over-the-counter in the United States as a supplement. And what makes this especially important is the fact that dietary sources of 5-HTP are insignificant.


L-tryptophan and 5-HTP, in supplement form, appear to be worth considering as one seeks relief from mood, anxiety, and sleep issues. But I have to emphasize that some studies have shown mixed results in terms of efficacy, and researchers have gone so far as to question the reliability of any conclusions drawn by a significant number of studies.

Finally, don’t ever, ever, ever forget – L-tryptophan and 5-HTP can lead to some very dangerous physical issues. And you just never know. So, please, do your research and consult your physician before beginning a regimen.

Oh, here’s a resource that may be helpful. It’s the website of the National Institutes of Health’s National Center for Complementary and Alternative Medicine. Check it out here.

That will be that. I hope the information will be helpful, and I encourage you to add your input by commenting. Thanks!

  • Jaime

    Okay! I remember that 1989 thing. It freaked me out and scared me off l-tryptophan, even though I had tried it and thought it was really helpful. I’ve been taking melantonin and l-theanine since I’ve weaned myself off (well, mostly) off trazodone. I swear, I’m going to keep trying and find the perfect combination that works for me. Keep up your awesome articles. I’m reading!! :)

    • And I’m glad you’re reading! How much Trazodone were you taking, if you don’t mind me asking? And what kind of side effects were you dealing with? Or were you? Hey, I can understand the emotional impact of the ’89 outbreak, but L-tryptophan seems to be safe now…

  • Jaime

    Hi Bill, I wasn’t taking that much. Just 100 mg at bedtime. The side effects were kind of insidious. The relief at being able to sleep overrode most of the side effects for at least several years. Once I made some major changes in my life, and came up for air after that, was when I noticed that I was essentially a zombie. I realized that I couldn’t function before noon. I felt I lived in a fog. I felt disconnected and really distanced from my life. Yes, it was partly circumstance, but it was also exacerbated by the trazodone fog.
    I am essentially off the trazodone now, and that fog has definitely lifted. I will NEVER go back to it or any other psycho-tropic drug to help me sleep. It served its purpose for its time, but, there’s something to be said for semi-natural sleep.

    • Thanks for sharing with us, Jaime. I’ve never used Trazodone – fortunately, sleep’s never been a real problem. But I’ve known folks who were at the max outpatient dosage of 400mg. Isn’t it wild that it’s an antidepressant! You know, you make a great point when you say, “Once I made some major changes in my life…” So many positive things happen in our lives when we endeavor to change – even if it’s incredibly painful at the time…

  • Linda

    Has anyone tried Tyrosine? or True Calm from NOW FOODS? I have been using it for five and a half years now. Its what I used when I kicked drugs and alcohol. Valerian Root With Calming Herbs is better than any sleeping pill and, there is no hangover. Please do your homework, especially if you take any prescription medications, before trying anything new.

    • Thanks for the tips, Linda. This is the very purpose of chipur! By the way, tyrosine is directly involved in the production of dopamine, norepinephrine, and epinephrine. All are monoamine neurotransmitters that loom large in mood and anxiety. The thyroid hormones, T3 and T4, are also derived from tyrosine.

  • Hi Katie! Appreciate your visit and comment. I suppose you could consider them both antidepressants; however, they aren’t prescription meds. Both are supplements. Again, glad you stopped by. The door’s always open!

  • Thanks for visiting chipur, Jimmy. I appreciate the information you presented. That’s how we all learn and heal – by sharing. chipur readers – click on Jimmy’s link “5-HTP” and see what he has to offer.

  • Pmtbell

    I have been taking trazodone for several years for insomnia at a dosage of 300 mg per night. I would like to  wean myself off this and wondered if I could do this with L-theanine and how to go about it?  Thanks