Arginine/ADMA Ratio is a biochemical marker that combines levels of the amino acid L-arginine and the methylated arginine derivative ADMA. L-arginine serves as the precursor for nitric oxide (NO) synthesis via nitric oxide synthase enzymes, while ADMA competes with or inhibits that enzyme family, so the ratio reflects balance in the NO pathway. ADMA was identified as an endogenous regulator of NO production and has been studied for its role in vascular biology. Researchers and clinicians use the ratio as a more informative indicator than either analyte alone because it captures substrate-to-inhibitor balance that influences vasodilation, platelet behavior, and cellular signaling related to vascular health.

Lower Arginine/ADMA Ratio (relatively higher ADMA or lower arginine) is associated with reduced biochemical capacity for nitric-oxide production. In clinical studies this pattern correlates with markers of impaired endothelial responsiveness, greater vascular resistance, and signals of oxidative or inflammatory stress, but interpretation depends on other measures such as lipids, inflammation, kidney function and redox markers. Higher Arginine/ADMA Ratio (relatively higher arginine or lower ADMA) suggests greater potential for nitric-oxide signaling and vessel responsiveness. Elevated ratios can reflect adequate substrate availability or lower inhibitor burden, but can also be influenced by recent diet, supplementation, kidney clearance, or concurrent lab findings; full-panel context is essential for meaningful interpretation.

Cardio Zoomer includes the Arginine/ADMA Ratio to assess endothelial nitric-oxide availability as part of the vascular function domain. This ratio complements lipids, inflammatory and oxidative-stress markers to clarify whether vascular signaling is a likely driver of cardiovascular patterns, helping clinicians prioritize further evaluation and personalized risk profiling.