L-Tyrosine (Free Form)

L-Tyrosine

Amino acid precursor to key neurotransmitters. Supports cognitive function under stress.

Part of L-Tyrosine amino acid
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Typical dose

100-1500 mg daily, often divided. Acute stress d...

Oral Oral safety: very low

About this supplement

L-Tyrosine (Free Form) is a non-essential, conditionally essential amino acid that serves as a precursor for the synthesis of catecholamine neurotransmitters (dopamine, norepinephrine, epinephrine) and thyroid hormones. The 'Free Form' designation indicates it is not bound to other amino acids in peptide chains, allowing for rapid absorption. It is synthesized in the body from phenylalanine but may become conditionally essential under stress, fatigue, or phenylketonuria (PKU). As a dietary supplement, it is used to support cognitive function, alertness, mood, and stress response, particularly in acute, demanding situations.

How much to take

Typical amount
100-1500 mg daily, often divided. Acute stress dosing studied up to 150 mg/kg body weight (approx. 10.5 g for 70 kg person) taken 60 minutes prior to stressor.
Suggested range
500-2000 mg daily

Potential benefits

Benefits linked to this supplement form:

Mood Support

Research strength: Early

 Focus and Alertness

Research strength: Moderate

 Physical Performance

Research strength: Early

 Cognitive Function (Under Stress)

Research strength: Strong

 Cognitive Support Under Stress

Research strength: Moderate

 Cognitive Support Under Acute Stress

Research strength: Moderate

 Mood and Alertness Support

Research strength: Early

 Support for Phenylketonuria (PKU) Management

Research strength: Strong

Things to watch for

Possible side effects linked to this form:

Gastrointestinal Upset

How serious: Mild

 Headache

How serious: Mild

 Gastrointestinal Discomfort

How serious: low

 Potential Interaction with Thyroid Medication

How serious: medium

 Increased Blood Pressure (Theoretical)

How serious: low

Health goals

Needs and goals this form may help with:

Other forms of L-Tyrosine

Compare absorption and active amounts with sibling forms:

N-Acetyl L-Tyrosine (NALT)

Acetylated form of L-Tyrosine for improved absorption. Precursor to key neurotra...
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Technical details â–¼

Chemical ID (CAS)

60-18-4

Formula

C9H11NO3

Physical properties

White crystalline powder or needles. Soluble in water (0.45 g/L at 25°C), insoluble in ethanol and ether. Melting point ~343°C (decomposes). Optically active (L-form).

How it’s made

Primarily produced via microbial fermentation using genetically modified Escherichia coli or other bacteria. Can also be synthesized chemically via amination of 4-hydroxyphenylpyruvic acid or extracted from hydrolyzed proteins (e.g., casein, soybean), though fermentation is the dominant commercial method for the L-isomer.