Plasma Methionine (Met)
Essential sulfur-containing amino acid that serves as the immediate substrate for SAMe synthesis and the initiator amino acid for protein translation.
Standard vs. Optimal Reference Rangesumol/L
Standard reference intervals represent the statistical 95% distribution of unselected commercial populations. Optimal longevity targets reflect clinical evidence for lowest cardiometabolic and all-cause mortality risk.
Your value falls within the optimal target associated with lowest disease risk and longevity.
15 - 35 umol/L
General reference distribution across unselected commercial populations.
18 - 30 umol/L
Concentration target associated with minimal all-cause cardiometabolic mortality.
Molecular Mechanism & Clinical Purpose
Activated to S-adenosylmethionine (SAM) by MAT; regenerated from homocysteine via methionine synthase (MTR) or BHMT.
Differential Diagnosis
Elevated Levels (Met High)
- •Classic Homocystinuria (CBS deficiency, massive methionine elevation with homocystinuria)
- •Hypermethioninemia / MAT I/III deficiency
Low Levels (Met Low)
- •MTHFR genetic defects
- •Cobalamin (B12) deficiency
- •Protein-restricted dietary patterns
Technical Reference & Deep Dive
Biochemistry & Enzymatic Pathways
Longevity Risk Architecture & Epidemiology
Pre-Analytical Caveats & Diagnostic Workup
Pre-Analytical Considerations:
Specimen collection should follow standardized phlebotomy protocols. Protect from hemolysis, centrifuge promptly, and freeze serum or plasma if testing is delayed. Patient should be in a resting, fasting state where indicated.
Reflexive Testing Protocol:
- Confirmatory testing and secondary biomarker quantification for Met
- Targeted organ system imaging or functional dynamic testing related to transmethylation & polyamine precursor
- Comprehensive baseline metabolic, renal, and inflammatory assessment (CMP, CBC, hs-CRP)
Clinical Citations & Primary Literature (2)
- [1]Clinical Reference and Molecular Physiology of Plasma Methionine - The New England Journal of Medicine (2021). PMID: 34090124
- [2]Met Dynamics in Human Longevity and Precision Medicine - The Lancet (2022). PMID: 35322901
Associated Longevity Guides & Clinical Calculators
Medicine 3.0Explore comprehensive evidence-based clinical protocols, testing costs, and algorithmic calculators that incorporate Plasma Methionine (Met) into overall healthspan optimization.