Does citrulline improve your pump and your reps?
Maybe a little. Six to eight grams of citrulline malate before lifting may buy a few extra reps across a hard, high-volume session, but it has not reliably improved maximal strength or endurance.
Citrulline is an amino acid that raises arginine more effectively than swallowing arginine itself. That can increase nitric-oxide availability and blood flow, which explains both the bigger-pump reputation and the tidy mechanism printed on pre-workout labels. A plausible mechanism, however, is not the same as a large performance effect.
The best pooled resistance-training result is small: six to eight grams of citrulline malate taken 40-60 minutes before training added about three repetitions across sessions averaging roughly fifty total reps. That is not three reps on every set. It is a modest difference spread across a lot of work, with substantial variation between studies.
What the pump does not prove
More blood flow can make a muscle feel fuller without making you stronger. When trials are pooled for actual strength outcomes, citrulline malate does not produce a reliable improvement. Aerobic and endurance results are similarly flat. There is also a messy product problem: “citrulline malate” powders do not always contain the advertised citrulline-to-malate ratio, so equal scoop sizes may not be equal doses.
Pure L-citrulline avoids that ratio problem, but the most commonly cited lifting protocol uses citrulline malate. Either way, stomach upset is possible at larger doses, and the effect is too small to rescue a poor session.
The takeaway
Citrulline sits in the optional tier. If you enjoy the pump and want to chase a tiny amount of extra high-rep volume, it is defensible. If your goal is maximal strength, endurance, or long-term muscle and your budget is limited, creatine, caffeine, protein, food, and sleep all deserve the money first.