Doctor's Note

This is the second of a four-part series (mentioned in Uprooting the Leading Causes of Death) on natural ways to boost serotonin in the brain. Yesterday’s video-of-the-day Human Neurotransmitters in Plants noted that plants themselves can contain serotonin. Tomorrow’s video-of-the-day A Better Way to Boost Serotonin will talk about getting dietary tryptophan into the brain, which we’ll then optimize in The Best Way to Boost Serotonin. Avoidance of soda (see Diet & Hyperactivity) and artificial colors (see Are Artificial Colors Bad for You?) may also improve behavior in children and adolescents. Also, check out my other videos on supplements–the good (see Safest Source of B12); the bad (see Update on Vitamin E); the ugly (see Update on Herbalife®); and the just plain snake oil (see Dietary Supplement Snake Oil). Unfortunately, too many people rely on the questionable advice from health food store employees (see my four-part video series that begins with Health Food Store Supplement Advice). 

For more context, check out my associated blog posts: How To Boost Serotonin NaturallyTop 10 Most Popular Videos of the YearSaffron vs. Prozac for Depression; and Treating Parkinson’s Disease with Diet.

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  • Michael Greger M.D.

    This is the second of a four-part series (mentioned in Uprooting the Leading Causes of Death) on natural ways to boost serotonin in the brain. Yesterday’s video-of-the-day Human Neurotransmitters in Plants noted that plants themselves can contain serotonin. Tomorrow’s video-of-the-day A Better Way to Boost Serotonin will talk about getting dietary tryptophan into the brain, which we’ll then optimize in Best Way to Boost Serotonin. Avoidance of soda and artificial colors may also improve behavior in children and adolescents. I’ve got dozens of videos on supplements–the good, the bad, the ugly and the just plain snake oil. Unfortunately, too many people rely on the questionable advice from health food store employees (see my four-part video series starting here). If you haven’t yet, you can subscribe to my videos for free by clicking here.

    • HemoDynamic, M.D.

      Dr G. must admire Sly Stallone, because this is an, “Avalance of ‘psycho’ Thrills” with his cliffhangers.

      • Elpoo

        I could totally hang like that off of a cliff ledge with one arm carrying 75 pounds of guns and ammo. I could. I just don’t want to is all.

  • Elpool

    You and your cliff hangers! :-)

  • AlexanderBerenyi

    I read that tyrosine and phenylalanine compete with tryptophan for absorption. Apparently because of this, some healthcare practitioners believe that food
    sources of tryptophan do not cause a significant enough increase in
    blood levels of tryptophan to produce therapeutic results—so therefore it ought to be taken as a supplement to increase its
    blood levels.

  • Bgrune

    Since 2002 when the ban on tryptophan was lifted there have been no cases of EMS liked to it. It is unlikely that you could achieve therapeutic levels of trytophan through diet.

  • Geoffreylevens

    Love what you do and this particular video I find a bit disingenuous or something. It is quite well known that the toxicity/deaths from tryptophan were caused by manufacturer contamination. One of the few, large manufacturing companies, Showa Denko K.K., Tokyo, had contaminated their fermentation tanks. This was jumped on by the FDA to crush the tryptophan supplement market just as the market for Prozac (approved just 2 years prior) was really taking off. Likely no connection but still, makes me wonder. It is not as if it was a big mystery why tryptophan use was associated w/ EMS. It was not the tryptophan, it was sloppy manufacturing and contamination.  Should we avoid lettuce because it has been sold contaminated.

    I totally agree that supplementing is 2nd choice at best with diet as 1st line treatment. But I certainly would not call tryptophan pills “the wrong way” nor would I imply that they are particularly dangerous.

    • You may be right but it looks like there isn’t a consensus. See

    • Allieb

      This is not correct. There have been cases since the disaster just check the Mayo Clinic site or the CDC. Let me tell you, it’s NOT WORTH IT! I would give anything to have my life back.

      Yes, Showa Denko KK produced contaminated product but it was because they eliminated one of the charcoal filtering processes in order to produce more bulk product…make more money. There’s nothing in place to stop this kind of disaster from happening again, with any supplement.

  • I totally agree — “Better safe than sorry.” I would rather err on the side of caution *especially* with supplements, when in doubt.

    • HemoDynamic, M.D.

      When in doubt–throw it out!

  • SJ M.D.

    History tells us that isolating one single factor from food can be dangerous (E-vitamin, betacarotene) – I wote for the package!

  • Nancywb947

    I am really intersted in your information but hate the video format.Would it be possible to include a written article with the information together with the video for those who prefer tro get information via print? Thanks.

    • Jhellen

      I agree.  I have a hearing loss, and either need closed captioning or text.  Wish this was possible.

      • Jhellen and Nancywb947: volunteers have begun transcribing Dr. Greger’s videos (in English and languages other than English). If you know anyone who could pitch in with the effort, please point them to these instructions:

    • beccadoggie10

      Dr. Greger already does this. Read the transcript! It’s right above the Doctor’s Note.

  • Ak42

    I love these videos. Keep them coming! Thank you!

  • Maui

    this is a really old story regarding Tryptophan… Jonathan Wright, MD covered it in great detail about 20 years ago. If memory serves it was a genetically modified strain of Japanese origin that caused the problem having nothing to do with the amino acid.
    That did not however stop the FDA from pulling it off the market in typical Gestapo technique. Were they only so responsive for the myriad drugs they approve!

  • BarbaraCharis

    I have been into nutritional research for 51 years…and personally experiment with food and substances, before recommending or panning them.  I have been using tryptophan for the last two years without a problem…it is a great sleep promoter, when taken at bedtime.  I go to sleep happy and wake up happy on a daily basis…and I am in my late seventies.

    • Syndee1on1

      I have great admiration for Dr. Greger and have followed his work for sometime and appreciate the time and energy he has put into it. But yes, I agree with many of the responses. I personally have never had to take tryptophan, perhaps due to my very healthy, nearly vegan diet, but for those that have a chemical imbalance and benefit from it’s use, more power to them for being smart enough to try it. I’m a certified nutrition consultant and equally important, I worked at a vitamin store for over 10 years and never heard of a negative incident, only positive, while using tryptophan. So while I’m ranting, I’m a bit offended by Dr. Greger’s comments about people that work at health food stores. I learned and experienced so much through the feedback of clients and the training the facility I worked for offered. There maybe exceptions, as there are in many occupations, but I have met and worked with many VERY knowledgable staff at various health food stores that have the utmost level of integrity helping clients improve their health through supplementations.

      • Geoffrey Levens

        I worked for many years in health food stores (including the “big dog” Whole Foods as well as small independent store).  My experience goes both ways. I have encountered quite a few employees who are very knowledgeable and I have also heard truly appalling ignorance being expressed as fact.  I think caveat emptor is always an excellent rule no matter what you are buying and no matter where.  I think it is most important of all when dealing with your own health and how your body is treated and what is going into it.  Sadly, our educational system and media train people to be ignorant sheep rather than to take responsibility and learn what is needed.

      • beccadoggie10

        The health food store I’ve frequented for the past 25 years, has had problems with both past owners, and some employees not knowing the side affects of the “supplements” and herbal remedies they are peddling to customers.

        For example, when I was looking for the essential oil of Calendula, another essential oil was thrust upon me from another part of the marigold, which while fragrant, was toxic if ingested.

        The owner downplayed my comments on the essential oil saying that it was pharmaceutical industry propaganda. This may be partially true. But, where there is smoke, there should be more investigation.

        I did not purchase what she was pushing, and that may have saved my dog’s life. I did bring in information that was on the web site, and was told we cannot believe everything on the web. True. But, we cannot believe everything a salesperson peddles to us either.

        This store owner-sales person died of liver damage, not from drinking, but from ingesting far too many supplements of comfrey, a natural plant which she declared “safe” –she and the industry who trained her.

        Investigate before you buy whether it is food, drugs, or supplements!!! And, it’s okay to walk away.

    • Cam Leviticus Gb

      Curious. I’ve read it is turned into 5-htp in small intestine by high ratio of good bacteria, probiotics. That 5-htp is brain converted to melatonin to sleep and serotonin for alert wakefulness and feel good. Sleepy daytime use. ??

  • Scott Thompson1

    I agree about having a written article with the video. We’re far out in the country and the video will not play with our extremely slow internet connection.

  • Liviu Deacu

    In Europe 5-HTP is used, could this one be also dangerous?

  • Eagles438

    I took tryptophan supplements which I might say were huge, some twenty seven years ago for a sleep problem.  During that period I experienced a severe gallbladder attack (unusual considering I was only 31yrs old and ate healthy). As a subsequence I lost my gallbladder.  The surgeon said it was so full of large gallstones that it had to be removed.  Shortly after I noticed that the tryptophan tablets were taken off the market!  I believe I lost my gallbladder because of tryptophan! For some people to die because of them, (it is believed), is terrible.

    • GeoffreyLevens

      It is well proven that the problems caused by tryptophan supplements were due to bacterial contamination in manufacture and had nothing at all to do with the tryptophan.  So far as I know, there is also zero connection between tryptophan intake in any form and gallbladder health (aside from it being one the essential ones to consume since we can’t synthesize it).  It is unfortunate that you lost your gallbladder but the stones and surgery had no connection to your taking tryptophan supplements.  Belief is quite different from causality or proof.

      • GeoffreyLevens

        Eagles438, also curious as to what you meant by “healthy diet”?  I would guess that about 95% of people, is asked would say they eat a healthy diet. If you get the actual detail of what they eat, more likely 5% or less actually do so.

  • Allieb

    I was one of the victim’s of L-tryptophan and it scares me to see this product back on the shelves. This is a horrible illness that ruins your life!! 

  • Renee Patton

    I love this site, and I have enjoyed many of these videos, but I must take exception with your assertion about “L-tryptophan supplements” causing those deaths, when the very article in your video stated–as have many of your informed readers below–that those deaths were all linked to ONE source (Showa Denko), which produced the contaminated supplements that caused ALL of the L-tryptophan deaths. Of course, Geoffrey Levens (below) pointed out the Prozac link–and I don’t think that was an accident. Big pharma spends tons of money on lobbying efforts–and the spreading of misleading information in this case caused widespread panic over the supplement, which led to a ban on L-tryptophan–meaning the consumer had fewer choices (especially between supplements or drugs–if you can’t get the supplement, you have to buy the drug–not counting the few educated folks who manage to get decent info on nutrition for countering deficiencies). This gave Prozac a big (unfair, artificially-created) market advantage. Glad the ban has since been lifted. 26 people died from that contaminated supply, but more than 2500 deaths have been linked to Prozac–almost 100x more than the contaminated L-tryptophan supplements! Don’t throw the baby out with the bath water!

  • beccadoggie10

    Eosinophilia–myalgia syndrome came about with the introduction into the marketplace of genetically engineered L-tryptophan, from a Japanese company.

    Because President Herbert Walker Bush was about to allow GMO foods and drugs into the marketplace, his administration banned all sources of L-tryptophan to save lives, or so they said.

    I’ve had a bottle of L-tryptophan, for decades which I have used sparingly whenever I absolutely cannot get to sleep, and I have never had any adverse health problem related to its ingestion.

    Now, we have myriad of foods and pharmaceuticals whose dna has been altered with antibiotic resistant bacteria, genes from other species, and possibly from other kingdoms, all because scientists can do this.
    And the FDA has a rubber stamped policy that these foods/drugs are not significantly different from any other foods, a policy likely written by Michael Taylor, then a lobbyist now a VP, for Monsanto.

    I don’t trust anything that the U.S. FDA puts out.

    Anyone guess what the health outcomes will be besides death and endocrine disruption?

    • disqus_URuRO073wC

      Buy what you want over the internet if you’re sure it’s safe. If it’s allowed in most countries, but not your own, it may be safe.

      Here in the UK we can buy some things that are banned in the USA but we can’t buy melatonin over the counter.

  • Steven Brown

    I have articles that say triptophan from food like white meat is turned into 5-htp by the small intestine and that this is what the brain uses to make serotonin for awake or melatonin for sleep. It said to take 5-htp pill with white meat. It did not mention L-triptophan pills. I may have felt some improvement doing this last mth. But hard to be sure

  • Cam Leviticus Gb

    I have article that says healthy gut bacteria needed to turn triptophan into 5-htp which the brain makes serotonin and melatonin from. It says take strong hq delayed release probiotic, 5-htp pill, triptophan rich white meat. Didn’t mention triptophan pills. Maybe due to past quality risk concerns. ?? 1 mth tried so far withmaybe some drep depression help. Would adding triptophan pills be worth trying. ??

  • Brux

    Is it too late to comment on this video? Coincidentally, I was reading about

    this very thing a few weeks ago and took the time to track it down and read

    about … OK, Wikipedia about it.

    Here is what Wikipedia says about Tryptophan as a dietary supplement:

    > Tryptophan supplements and EMS[edit]

    > There was a large outbreak of eosinophilia-myalgia syndrome (EMS) in the
    > U.S. in 1989, which caused 1,500 cases of permanent disability and at least
    > thirty-seven deaths. After preliminary investigation revealed that the outbreak
    > was linked to intake of tryptophan, the U.S. Food and Drug Administration
    > (FDA) banned most tryptophan from sale in the US in 1991, and other
    > countries followed suit.[38]

    > Subsequent epidemiological studies[39][40][41] however, were able to pinpoint
    > the syndrome to those exposed to specific batches of L-tryptophan supplied
    > by a single large Japanese manufacturer, Showa Denko KK.[42]

    > It eventually became clear that the cause had not been the tryptophan itself,
    > but rather that flaws in Showa Denko’s 1980s manufacturing process
    > (long since corrected) had allowed trace impurities to contaminate these
    > batches, and those impurities were in turn responsible for the 1989 EMS
    > outbreak.[38][42][43][44]

    So, I am wondering if this changes anything in your video about the safety or
    danger or taking L-Tryptophan supplements.

    This video is in a whole different century that those deaths supposedly due
    to Tryptophan were, and it was not mentioned about the defects in the
    manufacturing process.

    So, did Wikipedia not get something right, or is taking Tryptophan supplements
    not deadly? That seems like a strong claim to make if there is not hard evidence
    to support it?

    • Geoffrey Levens, L.Ac.

      Brux, FWIW I worked in supplement dept of Whole Foods while simultaneously being an acupuncturist at that time. The wiki article is correct, the problems were all from contamination due to mfg process and not the tryptophan. So far as I know it is quite safe as is 5-HTP which is what tryptophan becomes in your body on its way to becoming seratonin and is also available as a supplement. 5-HTP has a bit more chance to cause g.i. upset though as it (but not tryp.) can be converted to seratonin in the gut where it is biologically active

      • Brux

        Thanks Geoffrey, a lot of the videos here seem to rely on hyperbole and scare tactics just as much as any other food industry niche? My understanding was that the Japanese lab was using genetic engineering to make their tryptophan, but I would like to understand more about the problem, and if there is enough of a difference in the way other labs produce tryptophan to warrant any possible risk of any problem.

      • Jeffrey Baker

        I am considering the use of 5-HTP for migraine and looking for data on its safety and efficacy. I found the following resource on 5-HTP. It contains citations to over 100 scientific journal articles.

        BTW in Dr. Greger’s video he shows a diagram in which 5-HTP is an intermediate step from tryptophan to serotonin. I wonder why he did not elaborate on the role of 5-HTP and the wide use of it as a (safe, I think) supplement. I especially wonder this because in my reading on the topic many people’s bodies are not very effective in converting tryptophan to serotonin.

        • Brux

          I seem to recall this video claims that tryptophan can cause death.
          That seems to be not true. At least what I read was that there was
          a process a Japanese lab used to produce tryptophan that introduced
          a toxic impurity that caused the deaths of some people. A very serious
          problem which I think deserves to be addressed or understood – as
          well as are the labs producing tryptophan now using that process and
          have their been any subsequent problems, poisonings … and exactly
          what is the risk.

          How do we know that 5-HTP does not have problems in its production
          as well or is not toxic or a risk? I would like to hear more about this so
          this issue can be understood.

          • Jeffrey Baker

            Hi Brux – you might be interested in this study on safety of 5-HTP

          • Brux

            Hi Jeffrey thanks for the info.
            You know it is from 2004, right.
            It says L-Tryptophan has been pulled from the market, but
            today it is available all over, from Whole Foods Market to

            >> Extensive analyses of several sources of 5-HTP have shown no toxic contaminants similar to those associated with L-Trp, nor the presence of any other significant impurities. A minor chromatographic peak (peak X) reported in some 5-HTP samples lacks credibility due to chromatographic artifacts and infinitesimal concentrations, and has raised undue speculations concerning its chemistry and toxicity.

            Not really sure what that is committing to?

  • sephethus

    From Wikipedia: Subsequent epidemiological studies suggested that EMS was linked to specific batches of L-tryptophan supplied by a single large Japanese manufacturer, Showa Denko.[12][13][14][15] It eventually became clear that recent batches of Showa Denko’s L-tryptophan were contaminated by trace impurities, which were subsequently thought to be responsible for the 1989 EMS outbreak.[12][16][17] While a total of 60 trace contaminants were eventually identified, only 6 of them were associated with EMS.[3][18] The compound EBT (1,1′-ethylidene-bis-L-tryptophan, also known as “Peak E”) was the only contaminant identifiable by initial analysis, but further analysis revealed PPA (3-(phenylamino)-L-alanine, also known as “UV-5”), and peak 200 (2[3-indolyl-methyl]-L-tryptophan). Two of the remaining uncharacterized peaks associated with EMS have been labeled “UV-28” and “peak AAA”, with peak AAA being “the contaminant most significantly associated with EMS”.[3] The specific impurity or impurities responsible for the toxic effects was never firmly established. EBT has been frequently implicated as the culprit, but there is no statistically significant association between EBT levels and EMS.[3]

    • Brux

      Read the book “Altered Genes, Twisted Truth” by Stephen Drucker. The reason Showa Denko, and the world did a hush-hush about this is that the L-tryptophan was manufactured by genetic engineering, and as the mess unfolded they switched to different bacteria to produce the product. They made bacteria that produced successively more L-tryptophan, but also more impurities … so that relationship shows it was not due to the processing method or impurities, it was due to the GMO method itself and the fact that none of these things have ever been tested in any methodical complete way.

      So, think about it, a lot of food and nutrients are like this, and could be manufactured by bacteria. How many of the things we buy are produced in this manner, and how many are GMO? What about B12, or any of the many nutrients companies are looking for ways to produce fast, cheap and patentable?

  • AlPhur

    Hey, that’s BS.
    The supplement that caused oesinophiila was from a single manufacturer in Japan – it was incorrectly synthesised by pharma chemists. (Possibly deliberately? To orchestrate a ban because it was more effective than pharma drugs?) Although ‘chemically’ the same, the synthetic was structurally slightly different, and deadly. Proper L-trytophan was competing with sleeping pills and anti-depressants, and we can’t have a food supplement doing that, can we?
    As a reaction, the FDA did a favour to the owners of Pharma, and banned ~all~ L-tryptophan supplements, although they knew it was only the one brand at fault. And they know the true story, that they made a mistake, but they won’t un-ban it.

    The FDA is funded by the pharmaceutial industry, who also kindly lend support to politicians, and indeed to medical charities and websites who subversively support their cause (profits) by presenting skewed ‘facts’.

    What do you call alternative medicine that works?
    – Banned medicine.