Until 1990 tryptophan was by far the most popular natural sleep aid on the market. In 1990 the United States Food and Drug Administration pulled all tryptophan from store shelves due to a sudden outbreak of eosinophilic-myalgia syndrome that occurred among some people who had taken the sleep aid. Once the United States banned the nutrient many other countries soon followed. Ultimately almost five thousand people reported getting sick and twenty seven people died from the serious illness. The symptoms included muscle pain, weakness, and severe joint pain. A lengthy investigation determined that the problem was a contaminated batch that was manufactured by a Japanese company called Showa Denko KK, which had recently changed a production process to incorporate genetically engineered bacteria. The ban remained in effect until 2001.
In February of 2001, the FDA removed the ban on selling tryptophan, but kept an importation restriction. This is the statement that they released:
“Based on the scientific evidence that is available at the present time, we cannot determine with certainty that the occurrence of EMS in susceptible persons consuming L-tryptophan supplements derives from the content of L-tryptophan, an impurity contained in the L-tryptophan, or a combination of the two in association with other, as yet unknown, external factors.”
Since 2002, tryptophan has been available again in the United States and no reports of Eosinophilic-myalgia syndrome have been reported. There are definitely manufacturing companies currently making high quality tryptophans. I believe it is safe. It is a precursor of the sleep-inducing substances serotonin and melatonin. This means it is the raw material that the brain uses to build these relaxing neurotransmitters. By taking it in supplement form we are making more available to produce the neurotransmitters that are used to induce deep sleep.
Melatonin is currently the most popular and well respected of the natural sleeping aids available. It is a more direct precursor to serotonin than is tryptophan. Melatonin is also much cheaper. I almost always will recommend melatonin to my clients as the first thing to try to resolve sleep problems naturally. But one thing I have found is that for some reason the people that do not respond well to melatonin can sometimes find it effective. For many people it is a useful natural sleep aid, but tryptophan has never really regained the popularity that it once enjoyed prior to 1990.