Chinevere, T. D., Parcell, A. C., Sawyer, R. D., Creer, A. R., & Conlee, R. K. (2002). Effects of carbohydrate and L-tyrosine ingestion on endurance exercise performance. Medicine and Science in Sports and Exercise, 34(5), Supplement abstract 15.

The effects of tyrosine with or without CHO were assessed on endurance cycling performance. Trained cyclists performed at 70% VO2peak for 90 minutes followed by a time trial under four different feeding conditions (placebo, CHO-alone, CHO+tyrosine, tyrosine-alone).

VO2, rating of perceived exertion, and lactate did not differ between trials. Other conditions produced some changes in physiological factors. It was concluded that:

". . . carbohydrate ingestion enhances endurance cycling performance following 90 minutes of steady-state exercise and that tyrosine ingestion, either with or without carbohydrates, does not affect cycling performance" (p. S3)

Implication. Tyrosine does not improve endurance performance.

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