What Is HVA (Homovanillic Acid)? Normal vs Optimal Range Explained

HVA is the final metabolite of dopamine—the neurotransmitter that drives motivation, reward, focus, and movement. When your brain and adrenal glands produce dopamine, it gets broken down through COMT and MAO enzymes into homovanillic acid, which is excreted in urine. Measuring urinary HVA gives an indirect but clinically validated window into whole-body dopamine production. The standard clinical method uses a 24-hour urine collection, though spot urine normalized to creatinine provides a practical alternative for initial screening. The CTD maps over 320 compounds that interact with dopamine metabolism pathways including the enzymes that produce HVA. Lab reference ranges vary widely between laboratories, but the functional optimal zone of 1.5–5.5 mmol/mol creatinine reflects balanced dopamine synthesis and clearance without excessive catecholamine activity. Values below 1.5 suggest the dopamine production machinery is under-fueled—typically because one of the upstream cofactors (iron, B6, or tyrosine) is inadequate. Values above 5.5 indicate accelerated dopamine turnover consistent with chronic physiological stress or catecholamine-driven pathology.

Low HVA deserves particular attention because it identifies a correctable root cause for symptoms commonly attributed to psychiatric diagnoses. Dopamine synthesis requires a sequential chain of biochemical reactions: dietary tyrosine is converted to L-DOPA by tyrosine hydroxylase (which requires iron and tetrahydrobiopterin as cofactors), then L-DOPA is converted to dopamine by aromatic amino acid decarboxylase (which requires vitamin B6). PubMed indexes over 8,200 publications on HVA, with clinical analyses linking low urinary HVA to attention difficulties, motivational deficits, anhedonia, and restless legs syndrome—all symptoms that overlap heavily with ADHD, depression, and iron deficiency. Checking iron, ferritin, B6, and tyrosine alongside HVA can reveal that what looks like a psychiatric condition is actually a nutrient-driven production bottleneck amenable to targeted supplementation rather than psychotropic medication. This metabolic approach is particularly valuable in populations where iron deficiency is prevalent, including premenopausal women, endurance athletes, and frequent blood donors.

High HVA reflects rapid dopamine turnover, which occurs when the body is producing and breaking down dopamine at an accelerated rate. FAERS data document catecholamine disturbances across over 90 medication entries, including stimulants and antipsychotics that directly alter dopamine dynamics. Moderate HVA elevation often accompanies chronic psychological stress, where the sympathetic nervous system maintains elevated catecholamine output over weeks or months. Very high HVA—particularly when paired with elevated VMA (vanillylmandelic acid, the norepinephrine metabolite)—raises clinical suspicion for pheochromocytoma in adults or neuroblastoma in children, both catecholamine-secreting tumors. The HVA-to-VMA ratio provides additional diagnostic precision: a disproportionately high HVA relative to VMA suggests dopamine-dominant physiology, while balanced elevation suggests generalized catecholamine excess from stress or tumor. Serial HVA measurements over time provide more clinical value than single readings, since transient stress or dietary factors can influence individual samples.