In May 1990 GHB was introduced as a dietary supplement and was marketed to body builders, for help with weight control and as a sleep aid, and as a "replacement" for l-tryptophan, which was removed from the market in November 1989 when batches contaminated with trace impurities were found to cause eosinophilia-myalgia syndrome, although eosinophilia-myalgia syndrome is also tied to tryptophan overload. In 2001 tryptophan supplement sales were allowed to resume, and in 2005 the FDA ban on tryptophan supplement importation was lifted. By November 1989 57 cases of illness caused by the GHB supplements had been reported to the Centers for Disease Control and Prevention, with people having taken up to three teaspoons of GHB; there were no deaths but nine people needed care in an intensive care unit. The FDA issued a warning in November 1990 that sale of GHB was illegal. GHB continued to be manufactured and sold illegally and it and analogs were adopted as a club drug and came to be used as a date rape drug, and the DEA made seizures and the FDA reissued warnings several times throughout the 1990s.