Our proprietary “Star-Rating” system was developed to help you easily understand the amount of scientific support behind each supplement in relation to a specific health condition. While there is no way to predict whether a vitamin, mineral, or herb will successfully treat or prevent associated health conditions, our unique ratings tell you how well these supplements are understood by the medical community, and whether studies have found them to be effective for other people.
For over a decade, our team has combed through thousands of research articles published in reputable journals. To help you make educated decisions, and to better understand controversial or confusing supplements, our medical experts have digested the science into these three easy-to-follow ratings. We hope this provides you with a helpful resource to make informed decisions towards your health and well-being.
3 StarsReliable and relatively consistent scientific data showing a substantial health benefit.
2 StarsContradictory, insufficient, or preliminary studies suggesting a health benefit or minimal health benefit.
1 StarFor an herb, supported by traditional use but minimal or no scientific evidence. For a supplement, little scientific support.
This supplement has been used in connection with the following health conditions:
0.8 grams for every 2.2 lbs (1 kg) of body weight under medical supervision
Supplementing with glycine appears to help improve depression and mental symptoms and may reduce symptoms in people unresponsive to drug therapy.
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.
How It Works
How to Use It
Healthy people do not need to supplement with glycine. A physician should be consulted before supplemental glycine is used for the support of serious health conditions.
Where to Find It
Glycine is found in many foods high in protein, such as fish, meat, beans, and dairy.
Few people are glycine deficient, in part because the body makes its own supply of the nonessential amino acids.
Interactions with Supplements, Foods, & Other Compounds
At the time of writing, there were no well-known supplement or food interactions with this supplement.
Two double-blind studies have found that 0.4–0.8 mg/kg body weight per day of glycine can reduce the so-called negative symptoms of schizophrenia when combined with haloperidol and related drugs.9, 10 Negative symptoms include reduced emotional expression or general activity. The action of glycine in combination with the drugs was greater than the drugs alone, suggesting a synergistic action. Another double-blind study using approximately half the amount in the positive studies could not find any benefit from adding glycine to antipsychotic drug therapy.11 Patients with low blood levels of glycine appeared to improve the most when given glycine in addition to their antipsychotic drugs.12 No side effects were noticed in these studies, even when more than 30 grams of glycine were given daily.
In a small double-blind study, people with schizophrenia being treated with olanzapine experienced an improvement in their symptoms when glycine was added to their treatment regimen.13 The initial amount of glycine used was 4 grams per day; this was increased gradually over a period of 10 to 17 days to a maximum of 0.8 grams per 2.2 pounds of body weight per day.
In a small double-blind study, people with schizophrenia being treated with risperidone experienced an improvement in their symptoms when glycine was added to their treatment regimen.14 The initial amount of glycine used was 4 grams per day; this was increased gradually over a period of 10 to 17 days to a maximum of 0.8 grams per 2.2 pounds of body weight per day.
The use of glycine may interfere with the efficacy of clozapine as an antipsychotic drug. In a double-blind trial, people with chronic, treatment-resistant schizophrenia were given clozapine (400–1,200 mg per day) and either glycine (30 g per day) or placebo for 12 weeks.15 The combination of clozapine and glycine was not effective at decreasing symptoms. In contrast, participants who took clozapine without glycine had a 35% reduction in some symptoms. Therefore, the combination should be avoided until more is known.
Potential Negative Interaction
The Drug-Nutrient Interactions table may not include every possible interaction. Taking medicines with meals, on an empty stomach, or with alcohol may influence their effects. For details, refer to the manufacturers’ package information as these are not covered in this table. If you take medications, always discuss the potential risks and benefits of adding a supplement with your doctor or pharmacist.
No clear toxicity has emerged from glycine studies. However, people with kidney or liver disease should not consume high intakes of amino acids without consulting a healthcare professional.
The information presented in Aisle7 is for informational purposes only. It is based on scientific studies (human, animal, or in vitro), clinical experience, or traditional usage as cited in each article. The results reported may not necessarily occur in all individuals. For many of the conditions discussed, treatment with prescription or over the counter medication is also available. Consult your doctor, practitioner, and/or pharmacist for any health problem and before using any supplements or before making any changes in prescribed medications. Information expires June 2014.
How this information was developed to help you make better health decisions.
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