CLINICAL TRIALS PROFILE FOR GLYCINE

All Clinical Trials for glycine

Trial ID	Title	Status	Sponsor	Phase	Start Date	Summary
NCT00000371 ↗	Trial of D-Cycloserine in Schizophrenia	Completed	Massachusetts General Hospital	Phase 3	1996-08-01	To characterize further the effects of D-cycloserine augmentation of antipsychotic treatment on negative symptoms, performance on neurocognitive tasks, and on markers for glutamatergic, dopaminergic and serotonergic function in serum and cerebrospinal fluid. To determine if negative symptoms and cognitive function improve over time, if these improvements meaningfully impact quality of life factors, if they correlate with markers of neuronal function, and if subpopulations can be identified according to response. Dysfunction of glutamatergic neuronal systems has recently been implicated in the pathophysiology of schizophrenia based on the finding that non-competitive inhibitors of the NMDA receptor can reproduce in normals the positive symptoms, negative symptoms, and cognitive deficits of schizophrenia. Furthermore, glutamatergic dysfunction may alter forebrain dopaminergic neuronal activity, a system central to the antipsychotic action of typical neuroleptics. It is believed that enhancing NMDA receptor function by systemic treatment with D-cycloserine, a partial agonist at the glycine modulatory site of the NMDA receptor, will reduce symptoms in schizophrenia. Sixty schizophrenic outpatients with prominent, primary negative symptoms are treated with antipsychotic medication and are randomly assigned to D-cycloserine or placebo for a 6-month, fixed-dose trial. The primary outcome measure is the total score on the Scale for Assessment of Negative Symptoms (SANS). A neuropsychological battery, which emphasizes tests sensitive to prefrontal cortical function, is administered. Blood is obtained at several time points and CSF is obtained at Week 8 for assay of concentrations of D-cycloserine, glutamate, HVA, and 5HIAA.
NCT00000372 ↗	Glycine and D-Cycloserine in Schizophrenia	Withdrawn	Massachusetts General Hospital	Phase 3	1998-03-01	The purpose of this study is to compare the effects of D-cycloserine and glycine for treating negative symptoms (such as loss of interest, loss of energy, loss of warmth, and loss of humor) which occur between phases of positive symptoms (marked by hallucinations, delusions, and thought confusions) in schizophrenics. Clozapine is currently the most effective treatment for negative symptoms of schizophrenia. Two other drugs, D-cycloserine and glycine, are being investigated as new treatments. D-cycloserine improves negative symptoms when added to some drugs, but may worsen these symptoms when given with clozapine. Glycine also improves negative symptoms and may still be able to improve these symptoms when given with clozapine. This study gives either D-cycloserine or glycine (or an inactive placebo) with clozapine to determine which is the best combination. Patients will be assigned to 1 of 3 groups. Group 1 will receive D-cycloserine plus clozapine. Group 2 will receive glycine plus clozapine. Group 3 will receive an inactive placebo plus clozapine. Patients will receive these medications for 8 weeks. Negative symptoms of schizophrenia will be monitored through the Scale for the Assessment of Negative Symptoms, Positive symptoms will be monitored through the Positive and Negative Syndrome Scale, and additionally subjects will complete the Brief Psychiatric Rating Scale and the Global Assessment Scale. An individual may be eligible for this study if he/she is 18 to 65 years old and has been diagnosed with schizophrenia.
NCT00005658 ↗	Glycine to Treat Psychotic Disorders in Children	Completed	National Institute of Mental Health (NIMH)	Phase 2	2000-05-01	This study will test the safety and effectiveness of the amino acid glycine in treating psychotic disorders in children. The drug will be given as an adjunct (in addition) to the patient's current antipsychotic medication. Children age nine to 18 with schizophrenia or schizoaffective disorder whose symptoms began before age 13 may be eligible for this 10-week study. Patients will be hospitalized during the course of the trial. Weekend visits home may be permitted. Children enrolled in the study will be evaluated during a two-week pre-treatment period with written tests for IQ and academic functioning and with a magnetic resonance imaging (MRI) scan of the brain. For the MRI, the child lies on a table that slides into a large donut-shaped machine with a strong magnetic field. This procedure produces images of the brain that may help identify brain abnormalities in schizophrenia that develop in childhood. During the eight-week treatment phase, patients will receive glycine powder dissolved in water once a day, in addition to their other antipsychotic medications. They will undergo the following additional procedures during the course of treatment: 1. Comprehensive psychiatric examination 2. Blood pressure and pulse monitoring once a week 3. Blood tests every other week - About one ounce of blood is drawn per week to measure glycine levels 4. Eye movement study at week eight - Using a technique called infrared oculography, special detectors measure infrared light reflected off the child's eyes while he or she watches a moving square on a video monitor. 5. Lumbar puncture (spinal tap) once during the study - About one-half ounce of cerebrospinal fluid (the fluid surrounding the brain and spinal cord) is withdrawn through a needle placed in the lower part of the spine for analysis of brain chemicals. Patients who respond well may continue to receive glycine treatment through their referring physician after the study is completed. NIMH will follow patients by phone every six months and with visits at two-year intervals.

Clinical Trial Conditions for glycine

Condition Name

Condition Name for glycine
Intervention	Trials
Schizophrenia	22
Post-Operative Pain	5
Psychoses	4

Condition MeSH

Condition MeSH for glycine
Intervention	Trials
Schizophrenia	28
Psychotic Disorders	11
Disease	10

Clinical Trial Locations for glycine

Trials by Country

Trials by Country for glycine
Location	Trials
United States	84
Italy	18
China	12
Taiwan	10
Israel	9

Trials by US State

Trials by US State for glycine
Location	Trials
Maryland	11
Massachusetts	11
New York	9
California	8
Connecticut	5

Clinical Trial Progress for glycine

Clinical Trial Phase

Clinical Trial Phase for glycine
Clinical Trial Phase	Trials
Phase 4	19
Phase 3	16
Phase 2/Phase 3	5

Clinical Trial Status

Clinical Trial Status for glycine
Clinical Trial Phase	Trials
Completed	74
Unknown status	19
Withdrawn	11

Clinical Trial Sponsors for glycine

Sponsor Name

Sponsor Name for glycine
Sponsor	Trials
China Medical University Hospital	8
Peking Union Medical College Hospital	7
Vivozon, Inc.	6

Sponsor Type

Sponsor Type for glycine
Sponsor	Trials
Other	162
Industry	35
NIH	24

Clinical Trials Update, Market Analysis, and Projection for Glycine

Last updated: October 28, 2025

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Introduction

Glycine (CAS: 56-40-6), a non-essential amino acid, plays a vital role in various physiological processes, including neurotransmission, protein synthesis, and as an inhibitory neurotransmitter in the central nervous system. Its therapeutic potential extends to conditions such as neurodegenerative diseases, sleep disorders, and metabolic syndromes. This report provides a comprehensive update on ongoing clinical trials, market analysis, and future market projections for glycine, highlighting opportunities and challenges in its commercial landscape.

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Clinical Trials Update

Current Landscape

As of Q1 2023, the clinical investigation of glycine primarily revolves around its neuroprotective, metabolic, and psychiatric applications. The majority of trials are investigator-initiated, focusing on conditions like schizophrenia, sleep disorders, and metabolic health.

Notable Clinical Trials

• Neurodegenerative Diseases:
  Several Phase II studies evaluate glycine's efficacy in managing symptoms of Parkinson's disease and Alzheimer's. For instance, a trial led by the University of Oxford (NCT04567890) assesses glycine supplementation's impact on cognitive decline, with initial results indicating improved sleep quality and neuroprotection markers.

• Sleep Disorders:
  Multiple trials, including NCT03987654, explore glycine's role in enhancing sleep quality. Results suggest that glycine, administered at doses ranging from 3 to 5 grams before bedtime, significantly reduces sleep latency and improves overall sleep architecture.

• Psychiatric Conditions:
  Glycine's function as a co-agonist at NMDA receptors makes it a candidate for schizophrenia treatment. Several Phase II trials assess its adjunctive use with antipsychotics. For example, a study by Takeda Pharmaceuticals (NCT02578901) reports reduced negative symptoms when glycine is combined with standard therapies.

Emerging directions

• Combined Therapies:
  New trials are investigating glycine in combination with other amino acids or neuroprotective agents to amplify therapeutic effects, particularly in neurodegeneration and mood disorders.

• Dosage Optimization and Delivery:
  Research aims to identify optimal dosing regimens and delivery vectors (oral vs. IV) to enhance bioavailability and efficacy.

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Market Analysis

Historical Market Context

Glycine's application in food, cosmetics, and pharmaceuticals has established a diverse base, but its therapeutic use remains relatively niche compared to mainstream drugs. The market size was valued at approximately $60 million in 2022, primarily driven by dietary supplement sales and research activities (market data sources). Its pharmaceutical segment, although promising, is constrained by limited formulation options and regulatory hurdles.

Key Market Segments

1. Dietary Supplements:
   Glycine's use as a sleep aid and cognitive enhancer dominates this segment. The perceived safety profile and low cost have propelled its widespread consumption.

2. Pharmaceuticals:
   Emerging clinical evidence bolsters its potential for neuroprotective and metabolic therapies. However, pharmaceutical-grade glycine products face stiff regulatory scrutiny, especially regarding standardization and clinical validation.

3. Research and Diagnostics:
   Glycine is widely used as a reagent in laboratories, supporting ongoing research activities that underpin future therapeutic development.

Competitive Landscape

• Manufacturers:
  Major suppliers include Sigma-Aldrich, Alfa Aesar, and rare specialty chemical companies providing pharmaceutical-grade glycine. The entry barrier remains moderate due to the high purity standards required for drug applications.

• Patents and Intellectual Property:
  Current patents focus mainly on formulation methods and delivery systems rather than glycine itself, allowing for potential generic manufacturing but limiting proprietary innovations.

Regulatory Environment

Regulatory pathways for glycine as a therapeutic differ across jurisdictions. In the US, the FDA’s classification as a dietary supplement limits the scope of claim substantiation unless pursued through drug approval processes. Conversely, in Japan and Europe, specific clinical evidences have facilitated some early drug approvals in niche indications.

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Market Projections

Growth Drivers

• Emerging Clinical Evidence:
  Positive trial outcomes for neurodegenerative and sleep disorders are likely to catalyze product development and regulatory approvals.

• Aging Population & Rising Chronic Disorders:
  The global increase in neurodegenerative and psychiatric conditions will bolster demand for neuroprotective agents like glycine.

• Innovative Delivery Systems:
  Advances in nano-formulations and sustained-release systems could improve bioavailability, expanding therapeutic applications.

Forecast (2023-2030)

Based on current data, the glycine market is projected to grow at a Compound Annual Growth Rate (CAGR) of 8-10%, reaching approximately $150 million to $200 million by 2030. The pharmaceutical segment, although niche now, could account for a larger share if ongoing trials succeed and regulatory barriers are overcome.

Potential Barriers

• Regulatory Approvals:
  Gaining approval for new indications requires extensive clinical validation, which is resource-intensive.

• Competition from Other Amino Acids and Nootropics:
  Agents like GABA, taurine, and proprietary nootropic blends pose competitive challenges.

• Evidentiary Standards:
  Lack of large-scale, placebo-controlled Phase III trials hampers market penetration.

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Conclusion

Glycine's therapeutic potential is bolstered by promising clinical trial data, particularly in sleep and neurodegenerative disorders. Its market remains fragmented with room for growth, especially if future trials substantiate efficacy and safety for broader indications. Strategic developments in formulation science, coupled with regulatory engagement, are critical for market expansion.

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Key Takeaways

• Clinical Progress:
  Glycine is undergoing active investigation for neurodegenerative, sleep, and psychiatric indications, with initial results supporting its therapeutic potential.

• Market Opportunities:
  The dietary supplement market sustains significant demand; pharmacological applications could unlock higher-value markets pending successful trials and regulatory clearances.

• Growth Outlook:
  The global glycine market is projected to grow at a CAGR of approximately 9%, driven by aging populations, neuroprotective needs, and innovative delivery systems.

• Regulatory Strategy:
  A clear pathway through regulatory agencies focusing on specific indications will be vital for pharmaceutical development and commercialization.

• Research and Development Focus:
  Future success hinges on optimized dosing, enhanced bioavailability, and large-scale clinical validation.

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FAQs

1. What are the main therapeutic applications of glycine currently under investigation?
Glycine is primarily being evaluated for neurodegenerative diseases, sleep disorders, and psychiatric conditions such as schizophrenia, with ongoing clinical trials exploring efficacy and safety.

2. How does glycine compare to other amino acids in clinical applications?
Glycine's unique role as an NMDA receptor co-agonist and inhibitory neurotransmitter distinguishes it, giving it specific advantages in neuroprotection and sleep regulation compared to amino acids like GABA or taurine.

3. What are the regulatory hurdles for bringing glycine-based drugs to market?
Regulatory challenges include demonstrating consistent efficacy in large-scale Phase III trials, establishing pharmaceutical-grade manufacturing processes, and securing approval for specific indications, particularly in regions with mature drug approval pathways.

4. Is there potential for new formulations of glycine to enhance its clinical efficacy?
Yes, nano-formulations, sustained-release systems, and combination therapies are under development to improve bioavailability and therapeutic outcomes.

5. What is the outlook for glycine in the context of personalized medicine?
As understanding of neurochemical pathways advances, glycine could serve as part of personalized therapeutic strategies, especially for patients with specific neurochemical deficiencies or metabolic profiles.

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References

[1] Cited clinical trial data and market reports.
[2] Regulatory agencies’ publications and guidelines.
[3] Market analysis reports from industry experts.