There have been several reports of glycine reducing the symptoms of people with schizophrenia who were unresponsive to drug therapy.¹ Large amounts of glycine (0.8 gram per 2.2 pounds of body weight per day) have been shown to reduce negative symptoms of schizophrenia and improve psychiatric rating scores in one preliminary trial;² however, these results have not been repeated in later trials using similar (very high) amounts.^3,4 Earlier double-blind trials found significant improvements in depression and mental symptoms in people with schizophrenia who took glycine for six weeks.^5,6 Most trials demonstrated a moderate improvement in schizophrenia symptoms in those taking glycine supplements.⁷ Long-term supplementation with high amounts of glycine may be toxic to nerve tissue, however. Some preliminary successes have been reported using smaller amounts of glycine, such as 10 grams per day.⁸ Long-term studies on the safety of glycine therapy are needed.