Surprising
A randomized trial found L-arginine cleared lower ureter stones in 94% of people — but zeroed in on a narrow clinical population, and two other outcomes it measured showed no benefit.
This single study suggests L-arginine may be unexpectedly effective at helping small kidney stones pass, but it tested only 162 hospitalized patients, and its failure to reduce pain or analgesic use means the real-world advantage might be narrower than the headline rate suggests.
In a 4-week trial of 162 people with lower ureter stones, those taking 1,000 mg of L-arginine daily passed stones 94% of the time, far outpacing 31% for tamsulosin and 12% for placebo. However, the same study found L-arginine did not significantly lower pain episodes or the total amount of painkillers needed, so the benefit appears limited to stone clearance itself — not the associated discomfort.
Where this fits in the evidence
This is among the first studies we've indexed on L-Arginine for Increased Spontaneous Stone Expulsion Rate — treat it as an early signal until more research accumulates.
The study
L-arginine role for stone lower ureter: A randomized controlled trial.
- Randomized Controlled Trial (RCT)
- n = 162
- 2025-06-11
- Urolithiasis
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