In humans, a 15-gram dose of citrulline taken acutely (in the short term) does not appear to cause diarrhea or intestinal upset.[1] In this respect, citrulline is notably different from both ornithine and arginine, which may cause diarrhea at 10-gram doses when taken in boluses[2][3] due to limited absorption of these amino acids, which then proceed to the colon to cause osmotic diarrhea.[2]
Are there any side effects of taking high doses of citrulline?
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•Last Updated: May 16, 2025
A 15-gram dose of citrulline does not seem to cause diarrhea or intestinal upset in humans, unlike ornithine and arginine, which can lead to diarrhea at lower doses due to absorption issues. This indicates that citrulline may be better tolerated in high doses, compared to these other amino acids.