← The FormularyMuscle & performanceL-arginine
Also known as Arginine HCl, arginine AKGThe step immediately before nitric oxide, taken directly.
On its own, oral arginine is a weaker lever than its biochemistry suggests, because the gut takes a large cut. It earns its place next to citrulline rather than instead of it.
An amino acid the body uses to make nitric oxide. Present in most protein-containing food.
The enzyme nitric oxide synthase converts arginine into nitric oxide. Taking arginine orally raises the supply, though much of a dose is metabolised before it arrives — the reason citrulline sits beside it.
Supports normal blood flow as the direct precursor in the nitric-oxide pathway.
Anyone already taking citrulline; the two are usually formulated together for a reason.
Daily, with water. No loading, no cycling, no timing ritual.
Nothing you can feel on a given day. Judge it over weeks, alongside the rest of the routine.
The interesting literature is on the citrulline-to-arginine route rather than on arginine taken alone.
Read the labelNot an erection product and not a treatment for anything. Speak to a doctor first if you take blood-pressure or nitrate medication, or if you get cold sores — arginine is a known trigger for some people.
Evidence grades describe how well an ingredient is studied — A well-supported, C emerging — not a promise of results. Educational, not medical advice. Doses are typical ranges; follow the label on the product.