Animal studies show that neither oral nor intravenous delivery of arginine causes toxicity, even at high doses.[1][2] However, supplementation with arginine has been reported to cause adverse gastrointestinal effects in humans, including nausea, vomiting, and diarrhea.[3] For this reason, upper-limit guidelines of approximately 20 to 30 grams per day have been proposed for supplemental arginine intake,[4][5] but more long-term safety data in humans are needed to accurately define a tolerable upper intake level.
What are arginine’s main drawbacks?
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•Last Updated: May 16, 2025
Arginine supplementation can lead to gastrointestinal issues in humans, such as nausea, vomiting, and diarrhea, although animal studies showed no toxicity. As a precaution, the upper-limit guidelines suggest a daily intake of 20 to 30 grams, but further long-term safety evidence in humans is necessary.