L-Tyrosine Review

Tyrosine (you’ll sometimes see it called 4-hydroxyphenylalanine) is one of the amino acids used by cells to synthesize proteins. You can find it wherever you find casein (a type of protein found predominantly in dairy products such as milk, cheese, or cottage cheese). Tyrosine is a building block for neurotransmitters, which are chemicals used to relay, amplify and modulate signals between a neuron and another cell1.

L-Tyrosine is one diet pill ingredient that has quite a bit of support from actual research:

  • Studies finding L-Tyrosine useful during stressful conditions (working out comes to mind):
    • Hao S, Avraham Y, Bonne O, Berry EM (2001). “Separation-induced body weight loss, impairment in alternation behavior, and autonomic tone: effects of tyrosine”. Pharmacol. Biochem. Behav. 68 (2): 273–81. Link.
    • Reinstein DK, Lehnert H, Wurtman RJ (1985). “Dietary tyrosine suppresses the rise in plasma corticosterone following acute stress in rats”. Life Sci. 37 (23): 2157–63. Link.
  • An animal study (same as above) exhibiting reduction in stress-induced weight:
    • Hao S, Avraham Y, Bonne O, Berry EM (2001). “Separation-induced body weight loss, impairment in alternation behavior, and autonomic tone: effects of tyrosine”. Pharmacol. Biochem. Behav. 68 (2): 273–81. Link.
  • Several studies showing improvements in performance in human trials (again, the ability to work out more effectively and burn more calories certainly comes to mind):
    • Deijen JB, Orlebeke JF (1994). “Effect of tyrosine on cognitive function and blood pressure under stress”. Brain Res. Bull. 33 (3): 319–23. Link.
    • Deijen JB, Wientjes CJ, Vullinghs HF, Cloin PA, Langefeld JJ (1999). “Tyrosine improves cognitive performance and reduces blood pressure in cadets after one week of a combat training course”. Brain Res. Bull. 48 (2): 203–9. Link.
    • Mahoney CR, Castellani J, Kramer FM, Young A, Lieberman HR (2007). “Tyrosine supplementation mitigates working memory decrements during cold exposure”. Physiology and Behavior IN PRESS. Link.

So, when you have an effective ingredient, and you find it in a diet pill you’re considering, does that mean you should purchase the product? Maybe. Always be sure to check for how much of the effective ingredient is in there. Even an effective ingredient, backed by research, is ineffective if there isn’t enough of it. With L-Tyrosine, you want to look for daily dosage amounts of 500 to 1500 mg.

L-Tyrosine gets the thumbs up.

  1. http://en.wikipedia.org/wiki/Neurotransmitter [↩]