Pure Encapsulations L-Tyrosine contains the amino acid in its natural L-form. The amino acid tyrosine is important, among other things, for the formation of transport substances (catecholamines). Like all Pure Encapsulations products, L-tyrosine is also manufactured according to strict international standards. To ensure long-term and consistently high product quality, the entire process, from production to storage, is constantly monitored. Internal and external quality control is performed at every stage.