Compound or practice · Supplement
L-Arginine
The direct nitric-oxide precursor that mostly loses to citrulline because the gut destroys it first.
- Overall grade
- Grade C
- Last revised
- 3
- graded outcomes
- 0
- references listed
A structured monograph in Prometheus's bundled library. Its grades are the monograph's own reading of the evidence, not a peer-reviewed review.
3 at grade C · 1 at grade D — 4 graded rows
What is known
Each outcome with its grade (how strong the evidence is, A to D), the size of the effect where the entry records one, and how often studies agree.
- Blood pressureEvidence grade C
Modest reduction
Smallmixed
- Erectile functionEvidence grade C
Higher doses / combined
Smallmixed
- Exercise pump / performanceEvidence grade D
Poor oral absorption
Trivialmixed
Conditions
How the entry reads its effect on diagnosed conditions: the direction first, then the grade. Never a substitute for the person who treats you.
- Erectile dysfunction May improveEvidence grade CHigh-dose or combinedGrade C
What is uncertain
Read off the same rows as above. Nothing here is added that the entry does not itself record.
- Thin evidence: Blood pressure (grade C); Erectile function (grade C); Exercise pump / performance (grade D).
- Caution with Blood-pressure medications: Additive blood-pressure lowering.
Interactions
Documented pairings with supplements and medicines. A medicine on this list is a conversation for whoever prescribes it.
Blood-pressure medicationsCaution
Additive blood-pressure lowering.
L-CitrullineWorks together
Citrulline raises arginine more effectively — sometimes combined.
The evidence in words
What it is
L-arginine is a conditionally-essential amino acid and nitric-oxide precursor sold for pumps, blood pressure, and erectile function.
How it works
It is a substrate for nitric-oxide synthase, promoting vasodilation — but first-pass gut and liver metabolism blunts oral absorption badly.
What the evidence shows
Oral arginine's poor bioavailability makes citrulline the better NO route for most uses. It retains modest evidence for blood pressure and, at high doses or combined with other agents, erectile function; ergogenic effects are inconsistent.
How to use it
3–6 g if used; citrulline is usually preferable for the same goals.
Safety & interactions
GI upset at higher doses; additive blood-pressure lowering; caution with erectile-dysfunction drugs. L-Citrulline — Citrulline raises arginine more effectively — sometimes combined. antihypertensives — Additive blood-pressure lowering.
Bottom line
Outclassed by citrulline for pumps and endurance. Modest for blood pressure and erectile function; the gut is the bottleneck.
How it is used
As the entry records it, from the studies it summarises. Not a recommendation for you — doses that suit a trial population may not suit you.
- Standard
- 3–6 g; citrulline usually preferable.
Goes with
- L-CitrullineCitrulline raises arginine more effectively — sometimes combined.Evidence grade B
Related reading
Entries that share this one's tags or conditions.
- L-Arginine for Blood pressureEvidence grade C — Modest reductionEvidence grade C
- L-Arginine for Erectile dysfunctionEvidence grade C — High-dose or combinedEvidence grade C
- L-Arginine for Erectile functionEvidence grade C — Higher doses / combinedEvidence grade C
- L-Arginine for Exercise pump / performanceEvidence grade D — Poor oral absorptionEvidence grade D
Sources
This entry lists no references of its own.
Last revised . A grade is this entry's reading of the evidence, not medical advice.