Supplement

GlyNAC

GlyNAC combines glycine and N-acetylcysteine, two building blocks the body uses to make glutathione, a key antioxidant. People mostly look at it to restore low glutathione, and small trials in older adults with HIV and in people with type 2 diabetes found levels were corrected and oxidative stress markers fell. The evidence is limited: only about 36 people took part, the trials were small or open-label, and in the HIV trial benefits faded once supplementation stopped.

Sources: PMID 34587244; PMID 33007928; PMID 35052658

Updated 30 September 2026
How we grade
5 studies cited

Best evidence: Grade C
Conditions studied: 4
Outcomes: 10
Graded outcomes: 0046

Evidence by condition

Strong
Moderate
Limited
Very limited

4 conditions, plus general outcomes

Antioxidant Status

Antioxidant Status: outcomes studied for GlyNAC
Grade	Outcome	Effect	Size	Studies	People
	Glutathione Levels An open-label trial in 8 aging HIV patients (12 weeks) and a pilot study in 10 T2D patients (14 days) both found GlyNAC supplementation corrected glutathione deficiency, with benefits reversing upon cessation in the HIV trial washout period.	Improves (the measure goes up)	Moderate effect	3 studies	36 people
Studies that measured glutathione levels GlyNAC (Glycine and N-Acetylcysteine) Supplementation Improves Impaired Mitochondrial Fuel Oxidation and Lowers Insulin Resistance in Patients with Type 2 Diabetes: Results of a Pilot StudyAntioxidants (Basel, Switzerland) · 2022 · PMID 35052658 GlyNAC Supplementation Improves Glutathione Deficiency, Oxidative Stress, Mitochondrial Dysfunction, Inflammation, Aging Hallmarks, Metabolic Defects, Muscle Strength, Cognitive Decline, and Body Composition: Implications for Healthy AgingThe Journal of Nutrition · 2021 · PMID 34587244 Supplementing Glycine and N-acetylcysteine (GlyNAC) in Aging HIV Patients Improves Oxidative Stress, Mitochondrial Dysfunction, Inflammation, Endothelial Dysfunction, Insulin Resistance, Genotoxicity, Strength, and Cognition: Results of an Open-Label Clinical TrialBiomedicines · 2020 · PMID 33007928
	Oxidative Stress Two small human trials (HIV patients and T2D patients) found GlyNAC reduced oxidative stress markers. The T2D pilot showed a 47% reduction in methylglyoxal (p<0.01). A review of glutathione supplementation in HIV/TB populations supports these findings.	Improves (the measure goes down)	Moderate effect	3 studies	36 people
Studies that measured oxidative stress Efficacy and Safety of Glutathione Supplementation in Patients with HIV Infection and HIV-Tuberculosis Co-InfectionNutrients · 2026 · PMID 41754089 GlyNAC (Glycine and N-Acetylcysteine) Supplementation Improves Impaired Mitochondrial Fuel Oxidation and Lowers Insulin Resistance in Patients with Type 2 Diabetes: Results of a Pilot StudyAntioxidants (Basel, Switzerland) · 2022 · PMID 35052658 Supplementing Glycine and N-acetylcysteine (GlyNAC) in Aging HIV Patients Improves Oxidative Stress, Mitochondrial Dysfunction, Inflammation, Endothelial Dysfunction, Insulin Resistance, Genotoxicity, Strength, and Cognition: Results of an Open-Label Clinical TrialBiomedicines · 2020 · PMID 33007928

General

General: outcomes studied for GlyNAC
Grade	Outcome	Effect	Size	Studies	People
	Mitochondrial Function An open-label trial in aging HIV patients showed improved mitochondrial dysfunction, and a T2D pilot study found a 30% improvement in mitochondrial fatty acid oxidation (p<0.001) after just 14 days. An animal study in aging mice showed enhanced cardiometabolic enzyme activity in males.	Improves (the measure goes up)	Moderate effect	3 studies	36 people
Studies that measured mitochondrial function Sex Differences in Response to Diet Enriched With Glutathione Precursors in the Aging HeartThe Journals of Gerontology: Series A, Biological Sciences and Medical Sciences · 2025 · PMID 39492659 GlyNAC (Glycine and N-Acetylcysteine) Supplementation Improves Impaired Mitochondrial Fuel Oxidation and Lowers Insulin Resistance in Patients with Type 2 Diabetes: Results of a Pilot StudyAntioxidants (Basel, Switzerland) · 2022 · PMID 35052658 Supplementing Glycine and N-acetylcysteine (GlyNAC) in Aging HIV Patients Improves Oxidative Stress, Mitochondrial Dysfunction, Inflammation, Endothelial Dysfunction, Insulin Resistance, Genotoxicity, Strength, and Cognition: Results of an Open-Label Clinical TrialBiomedicines · 2020 · PMID 33007928
	Insulin Resistance Both an open-label trial in aging HIV patients (12 weeks) and a pilot study in T2D patients (14 days) showed reduced insulin resistance. The T2D pilot reported a 22% decrease in insulin resistance (p<0.01) along with a 25% reduction in free fatty acids.	Improves (the measure goes down)	Moderate effect	2 studies	36 people
Studies that measured insulin resistance GlyNAC (Glycine and N-Acetylcysteine) Supplementation Improves Impaired Mitochondrial Fuel Oxidation and Lowers Insulin Resistance in Patients with Type 2 Diabetes: Results of a Pilot StudyAntioxidants (Basel, Switzerland) · 2022 · PMID 35052658 Supplementing Glycine and N-acetylcysteine (GlyNAC) in Aging HIV Patients Improves Oxidative Stress, Mitochondrial Dysfunction, Inflammation, Endothelial Dysfunction, Insulin Resistance, Genotoxicity, Strength, and Cognition: Results of an Open-Label Clinical TrialBiomedicines · 2020 · PMID 33007928
	Inflammation An open-label trial in 8 aging HIV patients showed reduced inflammation markers after 12 weeks of GlyNAC. A review of glutathione supplementation in HIV/TB co-infection further supports anti-inflammatory effects of glutathione repletion.	Improves (the measure goes down)	Small effect	2 studies	16 people
Studies that measured inflammation Efficacy and Safety of Glutathione Supplementation in Patients with HIV Infection and HIV-Tuberculosis Co-InfectionNutrients · 2026 · PMID 41754089 Supplementing Glycine and N-acetylcysteine (GlyNAC) in Aging HIV Patients Improves Oxidative Stress, Mitochondrial Dysfunction, Inflammation, Endothelial Dysfunction, Insulin Resistance, Genotoxicity, Strength, and Cognition: Results of an Open-Label Clinical TrialBiomedicines · 2020 · PMID 33007928

Aging

Grip Strength: improves
Gait Speed: improves

Aging: outcomes studied for GlyNAC
Grade	Outcome	Effect	Size	Studies	People
	Grip Strength A single open-label trial in 8 aging HIV patients with 8 matched controls found improved grip strength after 12 weeks of GlyNAC supplementation, with benefits diminishing during the 8-week washout period.	Improves (the measure goes up)	Small effect	1 study	16 people
Studies that measured grip strength Supplementing Glycine and N-acetylcysteine (GlyNAC) in Aging HIV Patients Improves Oxidative Stress, Mitochondrial Dysfunction, Inflammation, Endothelial Dysfunction, Insulin Resistance, Genotoxicity, Strength, and Cognition: Results of an Open-Label Clinical TrialBiomedicines · 2020 · PMID 33007928
	Gait Speed A single open-label trial in 8 aging HIV patients found improved gait speed after 12 weeks of GlyNAC supplementation. Benefits reversed after supplementation ceased, suggesting ongoing use is needed.	Improves (the measure goes up)	Small effect	1 study	16 people
Studies that measured gait speed Supplementing Glycine and N-acetylcysteine (GlyNAC) in Aging HIV Patients Improves Oxidative Stress, Mitochondrial Dysfunction, Inflammation, Endothelial Dysfunction, Insulin Resistance, Genotoxicity, Strength, and Cognition: Results of an Open-Label Clinical TrialBiomedicines · 2020 · PMID 33007928

Age-Associated Memory Impairment and Cognitive Decline (AAMCD)

Cognitive Function: improves

Age-Associated Memory Impairment and Cognitive Decline (AAMCD): outcomes studied for GlyNAC
Grade	Outcome	Effect	Size	Studies	People	Studies list
	Cognitive Function An open-label trial in 8 aging HIV patients found improved cognitive performance on the Trail Making Test-B after 12 weeks of GlyNAC supplementation. No placebo-controlled RCTs confirm this finding.	Improves (the measure goes up)	Small effect	1 study	16 people
Studies that measured cognitive function Supplementing Glycine and N-acetylcysteine (GlyNAC) in Aging HIV Patients Improves Oxidative Stress, Mitochondrial Dysfunction, Inflammation, Endothelial Dysfunction, Insulin Resistance, Genotoxicity, Strength, and Cognition: Results of an Open-Label Clinical TrialBiomedicines · 2020 · PMID 33007928

Cardiovascular Health

Endothelial Function: improves
Cardiac Function (Aging): improves

Cardiovascular Health: outcomes studied for GlyNAC
Grade	Outcome	Effect	Size	Studies	People
	Endothelial Function A single open-label trial in 8 aging HIV patients found improved endothelial dysfunction markers after 12 weeks of GlyNAC supplementation. No controlled trials have replicated this finding.	Improves (the measure goes up)	Small effect	1 study	16 people
Studies that measured endothelial function Supplementing Glycine and N-acetylcysteine (GlyNAC) in Aging HIV Patients Improves Oxidative Stress, Mitochondrial Dysfunction, Inflammation, Endothelial Dysfunction, Insulin Resistance, Genotoxicity, Strength, and Cognition: Results of an Open-Label Clinical TrialBiomedicines · 2020 · PMID 33007928
	Cardiac Function (Aging) In a preclinical study of 21-month-old mice, 12 weeks of GlyNAC-enriched diet improved cardiometabolic enzyme activity and diastolic function in males but not females. Female mice showed a decline in exercise performance, indicating sex-differential effects.	Improves (the measure goes up)	Small effect	1 study
Studies that measured cardiac function (aging) Sex Differences in Response to Diet Enriched With Glutathione Precursors in the Aging HeartThe Journals of Gerontology: Series A, Biological Sciences and Medical Sciences · 2025 · PMID 39492659

Key findings

Glutathione LevelsAntioxidant StatusImproves (the measure goes up)
Oxidative StressAntioxidant StatusImproves (the measure goes down)
Mitochondrial FunctionImproves (the measure goes up)

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Grade C

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Studies cited

5 studies from PubMed

Efficacy and Safety of Glutathione Supplementation in Patients with HIV Infection and HIV-Tuberculosis Co-InfectionNutrients, 2026 · PMID 41754089
Sex Differences in Response to Diet Enriched With Glutathione Precursors in the Aging HeartThe Journals of Gerontology: Series A, Biological Sciences and Medical Sciences, 2025 · PMID 39492659
GlyNAC (Glycine and N-Acetylcysteine) Supplementation Improves Impaired Mitochondrial Fuel Oxidation and Lowers Insulin Resistance in Patients with Type 2 Diabetes: Results of a Pilot StudyAntioxidants (Basel, Switzerland), 2022 · PMID 35052658
GlyNAC Supplementation Improves Glutathione Deficiency, Oxidative Stress, Mitochondrial Dysfunction, Inflammation, Aging Hallmarks, Metabolic Defects, Muscle Strength, Cognitive Decline, and Body Composition: Implications for Healthy AgingThe Journal of Nutrition, 2021 · PMID 34587244
Supplementing Glycine and N-acetylcysteine (GlyNAC) in Aging HIV Patients Improves Oxidative Stress, Mitochondrial Dysfunction, Inflammation, Endothelial Dysfunction, Insulin Resistance, Genotoxicity, Strength, and Cognition: Results of an Open-Label Clinical TrialBiomedicines, 2020 · PMID 33007928