Compound or practice · Supplement
L-Citrulline
The arginine route that actually absorbs — a legitimate pump-and-reps pre-workout with modest blood-pressure benefit.
- Overall grade
- Grade B
- 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.
2 at grade B · 1 at grade C — 3 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.
- Resistance reps / pumpEvidence grade B
6–8 g pre-workout
Smallmixed
- Blood pressureEvidence grade B
Modest reduction
Smallmixed
- Endurance performanceEvidence grade C
Less consistent
Smalllow
What is uncertain
Read off the same rows as above. Nothing here is added that the entry does not itself record.
- Thin evidence: Endurance performance (grade C).
- Studies disagree: Resistance reps / pump (mixed agreement); Blood pressure (mixed agreement).
- Caution with Blood-pressure medications: Additive blood-pressure lowering — cuff it if on BP meds.
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 — cuff it if on BP meds.
Beta-AlanineWorks together
The two evidence-backed halves of most pre-workouts.
The evidence in words
What it is
L-citrulline is a non-essential amino acid that the body converts to arginine and then nitric oxide more effectively than arginine taken directly, which is largely destroyed in the gut. It is sold as pure citrulline or as citrulline malate.
How it works
By raising plasma arginine and nitric-oxide availability, citrulline promotes vasodilation and blood flow to working muscle, and it helps clear ammonia via the urea cycle, which may delay fatigue.
What the evidence shows
Reasonable evidence supports small improvements in resistance-exercise reps-to-failure and perceived exertion, and a genuine 'pump.' Endurance effects are less consistent. Separately, citrulline modestly lowers blood pressure. Doses in positive trials are 6–8 g pure citrulline (or ~8 g citrulline malate), taken ~60 minutes pre-exercise.
How to use it
6–8 g of L-citrulline (or 8 g citrulline malate) about an hour before training. Consistency isn't required day-to-day; it's an acute ergogenic.
Safety & interactions
Very well tolerated, with far less GI upset than arginine. Its blood-pressure lowering is additive with antihypertensive drugs. Beta-Alanine — The two evidence-backed halves of most pre-workouts. antihypertensives — Additive blood-pressure lowering — cuff it if on BP meds.
Bottom line
One of the few pre-workout ingredients with real, if modest, support. 6–8 g an hour before lifting for reps and pump; also a mild blood-pressure helper.
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.
- Pre-workout
- 6–8 g L-citrulline (or 8 g malate), ~60 min prior.
Goes with
- Beta-AlanineThe two evidence-backed halves of most pre-workouts.Evidence grade A
Related reading
Entries that share this one's tags or conditions.
- L-Citrulline for Blood pressureEvidence grade B — Modest reductionEvidence grade B
- L-ArginineThe direct nitric-oxide precursor that mostly loses to citrulline because the gut destroys it first.Evidence grade C
- L-Arginine for Blood pressureEvidence grade C — Modest reductionEvidence grade C
- L-Citrulline for Endurance performanceEvidence grade C — Less consistentEvidence grade C
Sources
This entry lists no references of its own.
Last revised . A grade is this entry's reading of the evidence, not medical advice.