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Metyrosine

Published: July 27, 2026Updated: August 25, 2026

Metyrosine is a diagnostic biomarker that measures the levels of an inhibitor of the enzyme tyrosine hydroxylase, which is crucial for catecholamine synthesis.

Quick summary

Metyrosine levels help diagnose conditions related to excess catecholamine production.

Medically reviewed by WellAlly Editorial TeamLast reviewed August 25, 2026Editorial policy

Key facts at a glance

Units
nmol/L
Clinical utility
diagnostic
Result kind
quantitative
FDA-cleared
FDA Cleared General Assay
interpretation: {"text":"0–500 nmol/L: Normal levels indicate no significant excess of catecholamine production.","label":"Normal"}; {"text":">500 nmol/L: Elevated levels may suggest the presence of a catecholamine-secreting tumor, such as pheochromocytoma.","label":"Elevated"}

Metyrosine is a medication and biomarker used to evaluate disorders associated with excessive catecholamine production, such as pheochromocytoma and paraganglioma. It works by inhibiting tyrosine hydroxylase, the rate-limiting enzyme in catecholamine synthesis.

The normal reference range for metyrosine is 0–500 nmol/L. Elevated levels may indicate the presence of a catecholamine-secreting tumor, while lower levels are less commonly seen but may reflect issues with enzyme function.

Testing for metyrosine levels is often done in conjunction with other tests, such as urine or plasma catecholamines, to provide a comprehensive assessment of catecholamine-related disorders.

Frequently asked questions

What is the primary use of measuring metyrosine levels?
Metyrosine levels are primarily used to diagnose and monitor conditions related to excessive catecholamine production, such as pheochromocytoma.
What factors can affect metyrosine levels?
Factors such as stress, certain medications, and underlying health conditions can influence metyrosine levels.
  1. 1
    Metyrosine: Uses, Side Effects, Interactions, Dosage, and WarningSource
  2. 2
    Tyrosine Hydroxylase InhibitorsSource

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This information is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment.

Medical Disclaimer

This content is for general informational and educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the guidance of a qualified healthcare provider with any questions you have about a medical condition, and never disregard professional medical advice or delay seeking it because of something you read here.

If you think you may have a medical emergency, call your local emergency number or go to the nearest emergency department immediately.

Medically reviewed by WellAlly Editorial Team Last reviewed August 25, 2026. · Read our editorial policy