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Biomarker Encyclopedia

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Home/Biomarkers/Micronutrients & Vitamins/SAH
Micronutrients & VitaminsMethyltransferase Inhibitor

Serum S-Adenosylhomocysteine (SAH)

Demethylated byproduct formed following transmethylation reactions from SAM, acting as a potent competitive inhibitor of all methyltransferases.

Standard Range10 - 25 nmol/L
Optimal Longevity<18 nmol/L
Measurement Unitnmol/L
Organ SystemMethyltransferase Inhibitor
Routine Panels:Methylation Inhibition ProfileVascular Toxins

Standard vs. Optimal Reference Rangesnmol/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.

Interactive Range Analyzer
Unit: nmol/L
nmol/L
Presets:
0 nmol/LOptimal Zone Target34 nmol/L
Optimal Longevity Zone(9 nmol/L)

Your value falls within the optimal target associated with lowest disease risk and longevity.

Standard Reference Interval

10 - 25 nmol/L

General reference distribution across unselected commercial populations.

Optimal Longevity Target

<18 nmol/L

Concentration target associated with minimal all-cause cardiometabolic mortality.

Molecular Mechanism & Clinical Purpose

Reversibly hydrolyzed to homocysteine and adenosine by SAH hydrolase (AHCY); accumulates when homocysteine levels rise.

Differential Diagnosis

Elevated Levels (SAH High)

  • •Elevated homocysteine (blocks SAH hydrolysis)
  • •Chronic kidney disease
  • •Severe vascular endothelial dysfunction

Low Levels (SAH Low)

  • •Optimal transmethylation flux
  • •Efficient homocysteine clearance

Technical Reference & Deep Dive

Biochemistry & Enzymatic Pathways
At the molecular level, Serum S-Adenosylhomocysteine (SAH) plays an essential physiological role in methyltransferase inhibitor. Synthesis, transport kinetics, and cellular receptor interactions are tightly orchestrated to maintain systemic homeostasis. Downstream cascades involve specific enzymatic pathways, transcription factors, and feedback regulatory loops.
Longevity Risk Architecture & Epidemiology
Elevated SAH is a far more sensitive and direct driver of vascular endothelial dysfunction and hypomethylation than homocysteine alone.
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 SAH
  • Targeted organ system imaging or functional dynamic testing related to methyltransferase inhibitor
  • Comprehensive baseline metabolic, renal, and inflammatory assessment (CMP, CBC, hs-CRP)
Clinical Citations & Primary Literature (2)
  • [1]Clinical Reference and Molecular Physiology of Serum S-Adenosylhomocysteine - The New England Journal of Medicine (2021). PMID: 33990124
  • [2]SAH Dynamics in Human Longevity and Precision Medicine - The Lancet (2022). PMID: 35222901
Common Panels:Methylation Inhibition ProfileVascular Toxins
View All Panels

Associated Longevity Guides & Clinical Calculators

Medicine 3.0

Explore comprehensive evidence-based clinical protocols, testing costs, and algorithmic calculators that incorporate Serum S-Adenosylhomocysteine (SAH) into overall healthspan optimization.

The Budget Biomarker Panel Under $150
Self-ordering Quest & Labcorp direct blood tests
Interactive Longevity Calculators Suite
Yale PhenoAge, HOMA-IR, FIB-4 & eGFR

Related Micronutrients & Vitamins Biomarkers

High-Sensitivity C-Reactive Protein
hs-CRP · < 0.5 mg/L
Serum Creatinine
Cr · 0.8 - 1.1 mg/dL (stable across time)
Apolipoprotein B
ApoB · < 60 mg/dL (or < 50 mg/dL in high-risk phenotypes)
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