Amino acid L-arginine blocks a key inflammation switch, NLRP3, in cells and mice — Nature Metabolism

A paper published in Nature Metabolism on 6 October 2026 reports that the common amino acid L-arginine acts as a natural brake on the NLRP3 inflammasome — a protein complex inside immune cells that switches on a major inflammatory pathway and is implicated in gout, neurodegeneration and other diseases.

Key findings (from the paper’s abstract)

• L-arginine binds directly to the NLRP3 protein at a site called Asp31, blocking its interaction with the adaptor protein ASC and so preventing the inflammasome from assembling and activating.
• In macrophages (immune cells), adding L-arginine inhibited NLRP3 activation, while depriving cells of it promoted activation.
• In mice, L-arginine treatment eased arthritis induced by urate crystals (a model of gout) and aluminium-induced peritonitis.
• In mouse models of Parkinson’s disease, supplementation reduced neuroinflammation and motor deficits, while deprivation worsened the disease.
• Patients with Parkinson’s disease had lower serum L-arginine levels.

The authors conclude that L-arginine supplementation is a “promising therapeutic avenue” for NLRP3-driven inflammatory diseases.

Limitations

• The treatment evidence comes from cells and mice; no clinical trial in people is reported.
• The lower L-arginine levels in Parkinson’s patients are an association and do not show cause and effect.
• Doses, safety and benefit in humans are unknown. L-arginine is sold as a supplement, but this study is not a reason to start taking it — talk to your doctor.