Safety concerns regarding impurities in L-Tryptophan associated with eosinophilia myalgia syndrome

L-tryptophan is one of the essential amino acids in humans and across the animal kingdom. It has been widely used as a feed additive for domestic animals and is also administered through dietary supplements in humans. Safety concerns have been raised however since a disease known as eosinophilia-myalgia syndrome (EMS) was reported to be related to L-tryptophan supplements. EMS is a rare condition characterized by inflammation in various organ systems including the muscles, skin, and lungs. Through several studies, it has been speculated that the six components generated during the process of L-tryptophan synthesis are related to the induction of EMS. In this review, we discuss the history of EMS and its controversial correlation with L-tryptophan use reported in several studies. Many in vitro and in vivo studies have been conducted to assess the putative correlation between impurities in L-tryptophan preparations and EMS, but no clear and convincing conclusions have been drawn so far.

Automated summary

L-tryptophan, an essential amino acid, is used as a feed additive for animals and as a dietary supplement for humans. Safety concerns have arisen due to its association with eosinophilia-myalgia syndrome (EMS), a rare condition characterized by inflammation in various organ systems. Studies have suggested that the impurities generated during the synthesis process of L-tryptophan may be related to the development of EMS. However, the correlation between L-tryptophan and EMS remains controversial, with inconclusive findings from in vitro and in vivo studies.