Blood Flow & Pump
Norvaline
An amino acid that inhibits arginase, theoretically extending the duration of arginine-driven NO production. Neurotoxicity concerns at high doses based on cell studies.
Effective Dose
100–250mg / day
per clinical evidence
Evidence Level
Insufficient
Blood Flow & Pump
Mechanism
Arginase inhibition (prolongs arginine availability)
primary action
Best For
NO prolongation
Pump
This profile is for informational purposes only and does not constitute medical advice. Consult a qualified healthcare professional before starting any supplementation, especially if you have pre-existing conditions or take medications.
What Is Norvaline?
Norvaline is a non-proteinogenic amino acid that inhibits arginase (the enzyme that degrades arginine to ornithine and urea). By blocking arginase, norvaline theoretically prolongs arginine availability for eNOS, extending NO production and pump duration.
How It Works: The Science
Arginase and eNOS compete for L-arginine as substrate. Arginase inhibition by norvaline shifts the balance toward eNOS, increasing NO synthesis from the same arginine pool. In theory this prolongs the NO-mediated vasodilation from citrulline or arginine supplementation.
Primary Mechanism
Arginase inhibition (prolongs arginine availability)
Evidence-Based Benefits
Dosage Guide
Effective Dose
100–250mg / day
100–250mg alongside citrulline or arginine. No clinically established human dose.
Safety Profile & Side Effects
Cell studies show mitochondrial toxicity at high concentrations — relevance to oral human dosing is unclear. Pre-clinical neurotoxicity signals are concerning. This ingredient deserves caution until more human safety data exists.
Who Should (and Shouldn't) Take It
Not currently recommended given limited evidence and pre-clinical safety signals. Citrulline alone is a safer, better-evidenced choice for NO support.
Frequently Asked Questions
Related Ingredients
Medical Disclaimer
Ingredient profiles are for informational purposes only and do not constitute medical advice. Consult a qualified healthcare professional before starting any supplementation, especially if you have pre-existing conditions or take medications. Full disclaimer →