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Completed

NCT Number: NCT07643675

Glycine Supplementation Improves Cognitive Performance in Mexican Older Adults

The purpose of this study was to evaluate the effects of daily glycine supplementation on metabolic health and cognitive performance in older adults. Over a period of six months, participants received 1,000 mg of glycine per day to determine if this amino acid could improve markers of insulin resistance, glucose metabolism, and cognitive functions such as memory and executive tasks.

The research aimed to identify whether this nutritional intervention provides a safe and effective strategy to support healthy aging, focusing on the link between metabolic balance and brain health in the elderly population.

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Key information

Conditions

Older Adults With Cognitive Decline Aging Cognition Disorders Cognitive Dysfunction Glucose Metabolism Disorders Hyperinsulinism Inflammation Insulin Resistance Insulin Resistance Syndrome Mental Disorders Metabolic Diseases Metabolic Syndrome Neurocognitive Disorders Nutritional and Metabolic Diseases Pathologic Processes Pathological Conditions, Signs and Symptoms

Age range

60 year–80 year

Sex eligibility

All sexes

Study type

Interventional

Phase

Not applicable

Primary location

Escuela Superior de Medicina

México, State of Mexico, 01710, Mexico

About this study

A 6-month longitudinal study was conducted, featuring a glycine supplementation phase followed by a dietary maintenance period. Cognitive assessments and serum BDNF levels were monitored at baseline, 3 months (T3), and 6 months (T6). Which included the evaluation of fasting glucose, insulin levels, insulin resistance indices, and specific metabolic biomarkers. Concurrently, cognitive functions were evaluated utilizing standardized neuropsychological instruments to measure changes in memory, attention, and executive function. Linear Mixed-Effects Models (LMM) were used to analyze temporal trajectories.

Who can participate

Healthy volunteers accepted: Yes

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

-Individuals across all nutritional statuses according to Body Mass Index (BMI): underweight, normal weight, overweight, and obesity.

Exclusion criteria

  • Clinically relevant comorbidities (requiring patient hospitalization or a diagnosis of any infectious/contagious disease).
  • Consumption of polyphenol-based supplements or herbal blends within the two weeks prior to the study.
  • Mental incapacity.
  • Lack of willingness.
  • Language barriers that prevent adequate understanding or co-operation.

Treatment and study plan

Glycine

Dietary Supplement

Oral supplementation of glycine at a dose of 1,000 mg per day, administered daily over a 6-month period.

Primary outcomes

  1. Brain-Derived Neurotrophic Factor (BDNF) levels

    Time frame: Baseline (T0), 3 months (T3) and 6 months (T6)

    Serum concentrations of Brain-Derived Neurotrophic Factor (BDNF) measured via ELISA. Unit of Measure: pg/mL

Secondary outcomes

  1. Cognitive performance evaluated by the Cognitive performance was assessed using the Montreal Cognitive Assessment (MoCA).

    Time frame: Baseline (T0), 3 months (T3) and 6 months (T6)

    Cognitive performance assessed using the Cognitive performance was assessed using the Montreal Cognitive Assessment (MoCA). Total scores range from 0 to 30, where higher scores indicate better cognitive performance.

    • ≥ 26 points: Considered within the normal range.
    • 18 - 25 points: Commonly associated with Mild Cognitive Impairment (MCI).
    • 10 - 17 points: Suggests Moderate Cognitive Impairment.
    • < 10 points: Suggests Severe Cognitive Impairment.

Other outcomes

  1. Cognitive performance evaluated byMini-Mental State Examination (MMSE).

    Time frame: Baseline (T0), 3 months (T3) and 6 months (T6)

    Cognitive performance assessed using the Mini-Mental State Examination (MMSE). Total scores range from o 27 - 30 points: Normal (No cognitive impairment).

    • 24 - 26 points: Mild cognitive impairment / Borderline.
    • 18 - 23 points: Mild to moderate cognitive impairment.
    • 10 - 17 points: Moderate to severe cognitive impairment.
    • 0 - 9 points: Severe cognitive impairment.

Sponsors and collaborators

Lead sponsor

Brenda Sarahí Beristain Lujano

Other

Collaborators

  • Instituto de Seguridad y Servicios Sociales de los Trabajadores del Estado
  • National Polytechnic Institute, Mexico

Registry information

Acronym: Glycine

Important dates

Study start
2024
Primary completion
2025
Study completion
2025
First posted
Jun 11, 2026
Registry last updated
Jun 15, 2026

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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