What is the Difference Between L-tyrosine and Tyrosine?

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L-tyrosine and tyrosine refer to the same amino acid, but they differ in their optical activity and stereochemistry. The key difference between L-tyrosine and tyrosine is the ability to rotate plane polarized light. Tyrosine is a biologically active, naturally occurring, non-essential amino acid that can occur in two forms of isomers due to the formation of two different enantiomers around the chiral carbon atom. These are known as L- and D-forms or equivalent to left-handed and right-handed configurations, respectively.

L-tyrosine and D-tyrosine have identical physical properties, but they rotate plane polarized light in different directions, resulting in substantially different biological effects and functional properties. Some differences between L-tyrosine and tyrosine include:

  • Taste: L-forms of amino acids, including L-tyrosine, are considered tasteless, while D-forms, such as tyrosine, tend to have a sweet taste.
  • Abundance: L-forms of amino acids, including L-tyrosine, are the most abundant form in nature. Industrially, L-tyrosine is produced by a microbial fermentation process and is mainly utilized in the pharmaceutical and food industry as either a dietary supplement or food additive.

Despite these differences, both L-tyrosine and tyrosine serve the same functional role in the body, as they are used to make neurotransmitters like dopamine, norepinephrine, and epinephrine. These neurotransmitters are vital for mental health, cognition, behavior, and stress response.

Comparative Table: L-tyrosine vs Tyrosine

L-tyrosine and tyrosine are both terms used for the same amino acid, which is a non-essential amino acid synthesized from L-phenylalanine in the body. Tyrosine, also known as L-tyrosine, is used to make the catecholamine neurotransmitters dopamine, norepinephrine, and epinephrine, which are vital for mental health, cognition, behavior, and stress response.

N-Acetyl L-tyrosine (NALT) is a derivative of L-tyrosine, which is created by adding an acetyl group to L-tyrosine. When taken as a supplement, NALT breaks down in the kidneys back into L-tyrosine. It is often used as an alternative to plain L-tyrosine in supplements due to its reported increased bioavailability.

Here is a comparison table of L-tyrosine and N-Acetyl L-tyrosine:

Feature L-Tyrosine N-Acetyl L-Tyrosine (NALT)
Form Amino acid Derived from L-tyrosine
Role Catecholamine neurotransmitters: dopamine, norepinephrine, and epinephrine Catecholamine neurotransmitters, kidney health
Sources Dairy products, meat, fish, eggs, and oats Supplements, nootropic stacks, and workout stacks
Thyroid Hormones Yes (contributing to the production of T3 and T4) Yes (contributing to the production of T3 and T4)
Benefits Enhances working memory, executive function, creative flow states, and cognitive flexibility Potentially increased bioavailability

Both L-tyrosine and NALT are considered effective for their respective benefits, but NALT is often preferred due to its potential increased bioavailability.