A 13-week subchronic oral toxicity study of l-serine in rats

A subchronic oral toxicity study was conducted to evaluate the safety of l-serine in Sprague–Dawley rats. The test article was administered once daily by gavage in male and female rats at dose levels of 0, 500, 1500, and 3000 mg/kg body weight/day for 13 weeks. Daily clinical signs, body weight, and food consumption were not affected by ingestion of the test article. There were no treatment-related adverse effects on urinalysis, hematology, serum biochemistry, organ weights, gross and histopathological examination. It was concluded that the no-observed-effect level (NOEL) for l-serine was 3000 mg/kg bw/day for both genders.