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Optimal range: 0 - 0.12 mmol/mol creatinine
Produced from bacterial degradation of unabsorbed phenylalanine.
Optimal range: 40 - 74 umol/L
Phenylalanine is an essential amino acid found in most foods which contain protein such as meat, fish, lentils, vegetables, and dairy. Phenylalanine is the precursor to another amino acid, tyrosine. Because tyrosine is needed to form several neurotransmitters (dopamine, epinephrine, and norepinephrine), as well as thyroid hormone and melanin, phenylalanine intake is important.
Optimal range: 5 - 239 umol/g Cr
Phenylalanine is an essential amino acid found in most foods which contain protein such as meat, fish, lentils, vegetables, and dairy.
Phenylalanine is the precursor to another amino acid, tyrosine. Because tyrosine is needed to form several neurotransmitters (dopamine, epinephrine, and norepinephrine), as well as thyroid hormone and melanin, phenylalanine intake is important.
Optimal range: 6.07 - 17.46 qmol/dL
Phenylalanine is an essential amino acid found in most foods which contain protein such as meat, fish, lentils, vegetables, and dairy. Phenylalanine is the precursor to another amino acid, tyrosine. Because tyrosine is needed to form several neurotransmitters (dopamine, epinephrine, and norepinephrine), as well as thyroid hormone and melanin, phenylalanine intake is important.
Optimal range: 5 - 20 mmol/mol creatinine
Phenylalanine is an essential amino acid found in most foods which contain protein such as meat, fish, lentils, vegetables, and dairy. Phenylalanine is the precursor to another amino acid, tyrosine. Because tyrosine is needed to form several neurotransmitters (dopamine, epinephrine, and norepinephrine), as well as thyroid hormone and melanin, phenylalanine intake is important.
Optimal range: 2 - 10 mmol/mol creatinine
Phenylalanine is an essential amino acid found in most foods which contain protein such as meat, fish, lentils, vegetables, and dairy. Phenylalanine is the precursor to another amino acid, tyrosine. Because tyrosine is needed to form several neurotransmitters (dopamine, epinephrine, and norepinephrine), as well as thyroid hormone and melanin, phenylalanine intake is important.
Optimal range: 7.4 - 69.6 nmol/mg Creatinine
Phenylalanine is an essential amino acid found in most foods which contain protein such as meat, fish, lentils, vegetables, and dairy. Phenylalanine is the precursor to another amino acid, tyrosine. Because tyrosine is needed to form several neurotransmitters (dopamine, epinephrine, and norepinephrine), as well as thyroid hormone and melanin, phenylalanine intake is important.
Optimal range: 25 - 100 qM/g creatinine
LEARN MOREOptimal range: 35.8 - 76.9 umol/L
Phenylalanine is a precursor for the amino acid tyrosine, which is essential for making neurotransmitters (e.g. epinephrine, norepinephrine, dopamine) and thyroid hormone. Neurotransmitters are the chemicals that communicate between nerve cells in the brain. It can relieve pain, alleviate depression, and suppress the appetite. Low levels may indicate a stressful lifestyle, leading to memory loss, fatigue, and depression.
Optimal range: 6.07 - 17.46 Units
Phenylalanine is an essential amino acid found in most foods which contain protein such as meat, fish, lentils, vegetables, and dairy.
Phenylalanine is the precursor to another amino acid, tyrosine. Because tyrosine is needed to form several neurotransmitters (dopamine, epinephrine, and norepinephrine), as well as thyroid hormone and melanin, phenylalanine intake is important.
Optimal range: 7 - 92 micromol/g creatinine
Phenylalanine is an essential amino acid found in most foods which contain protein such as meat, fish, lentils, vegetables, and dairy. Phenylalanine is the precursor to another amino acid, tyrosine. Because tyrosine is needed to form several neurotransmitters (dopamine, epinephrine, and norepinephrine), as well as thyroid hormone and melanin, phenylalanine intake is important.
Optimal range: 31 - 100 µmol/g Crea
Phenylalanine is an essential aromatic amino acid that serves as the biochemical starting point for several critical compounds in the body, including the catecholamine neurotransmitters — dopamine, noradrenaline, and adrenaline. On the Neurotransmitter XL panel, phenylalanine provides valuable insight into neurotransmitter synthesis capacity, stress metabolism, and amino acid balance.
Because the body cannot produce phenylalanine, it must be obtained from dietary protein sources such as meat, eggs, fish, dairy, soy, and legumes. Once absorbed, phenylalanine is converted into tyrosine via the enzyme phenylalanine hydroxylase (PAH), a process dependent on the essential cofactor tetrahydrobiopterin (BH4), as well as iron and vitamin B6. Tyrosine then serves as the substrate for dopamine synthesis, which can subsequently be converted into noradrenaline and adrenaline.
Thus, phenylalanine is the first building block in the catecholamine biosynthetic chain, influencing motivation, alertness, focus, stress resilience, and energy.
Optimal range: 30 - 130 qmol/24 hours
LEARN MOREOptimal range: 51.2 - 121 umol/L
Phenylalanine is an essential amino acid found in most foods which contain protein such as meat, fish, lentils, vegetables, and dairy. Phenylalanine is the precursor to another amino acid, tyrosine. Because tyrosine is needed to form several neurotransmitters (dopamine, epinephrine, and norepinephrine), as well as thyroid hormone and melanin, phenylalanine intake is important.
Optimal range: 42 - 95 µmol/L , 4.2 - 9.5 µmol/dL
Phenylalanine is a precursor for the amino acid tyrosine, which is essential for making neurotransmitters (e.g. epinephrine, norepinephrine, dopamine) and thyroid hormone. Neurotransmitters are the chemicals that communicate between nerve cells in the brain. It can relieve pain, alleviate depression, and suppress the appetite. Low levels may indicate a stressful lifestyle, leading to memory loss, fatigue, and depression.
Optimal range: 31.7 - 71 nmol/ML
Final products include: DOPA, dopamine, norepinephrine, epinephrine, thyroid hormones, melanin, in TCA cycle, or 4-hydroxyphenylacetic acid.
Optimal range: 8 - 71 micromol/g creatinine
Phenylalanine is a precursor for the amino acid tyrosine, which is essential for making neurotransmitters (e.g. epinephrine, norepinephrine, dopamine) and thyroid hormone. Neurotransmitters are the chemicals that communicate between nerve cells in the brain. It can relieve pain, alleviate depression, and suppress the appetite. Low levels may indicate a stressful lifestyle, leading to memory loss, fatigue, and depression.
Optimal range: 0 - 2.01 Ratio
The Phenylalanine/Tyrosine Ratio evaluates the body’s ability to convert phenylalanine to tyrosine; Conversion enzyme requires tetrahydrobiopterin (BH4), niacin (B3), and iron as cofactors.
Optimal range: 0.53 - 1.46 Ratio
The Phenylalanine/Tyrosine Ratio evaluates the body’s ability to convert phenylalanine to tyrosine; Conversion enzyme requires tetrahydrobiopterin (BH4), niacin (B3), and iron as cofactors.
Optimal range: 0 - 1.19 Ratio
The Phenylalanine/Tyrosine Ratio evaluates the body’s ability to convert phenylalanine to tyrosine; Conversion enzyme requires tetrahydrobiopterin (BH4), niacin (B3), and iron as cofactors.