Glynac

1. What conditions has GlyNAC been studied for?

• Human aging/age-associated physiological decline in older adults (clinical trials in older adults): oxidative stress, glutathione (GSH) deficiency, mitochondrial dysfunction (including impaired mitochondrial fuel/fatty-acid oxidation), inflammation, endothelial dysfunction, insulin resistance, elevated blood pressure/waist circumference, reduced physical function (gait speed, strength, 6-minute walk), and cognitive outcomes.

• Age-associated cognitive decline (mouse study): cognitive impairment with brain oxidative stress, mitochondrial dysfunction/energetics defects, altered autophagy/mitophagy, inflammation, genomic damage, and changes in neurotrophic factors.

• Longevity/healthspan biology (mouse lifespan study): lifespan plus multi-organ aging defects (heart, liver, kidney) including GSH deficiency, oxidative stress, mitochondrial dysfunction, abnormal mitophagy and nutrient sensing, and genomic damage.

• Spinal cord injury (SCI) (rat studies): motor and sensory recovery and prevention of skeletal muscle atrophy after SCI; including studies of GlyNAC alone and combined with body-weight support treadmill training.

• COVID-19-related oxidative stress/GSH deficiency (observational human study): hospitalized COVID-19 patients were measured for GSH deficiency and oxidative stress markers; this study does not report GlyNAC treatment, but provides rationale for targeting GSH.

• Type 2 diabetes (T2D): one abstract is truncated, but it indicates T2D is associated with mitochondrial dysfunction and insulin resistance and references prior work involving GSH and GlyNAC precursors; however, the provided text does not include results.

2. Does it work in treating those conditions? Summarize the evidence.

• Older adults (randomized placebo-controlled trial, 16 weeks): Older adults receiving GlyNAC (vs isonitrogenous alanine placebo) showed improvements/corrections in intracellular GSH deficiency, oxidative stress, mitochondrial dysfunction (and “defective molecular regulation”), inflammation, endothelial dysfunction, insulin resistance, multiple “hallmarks of aging,” physical function (gait speed, muscle strength, 6-minute walk), and also improvements in waist circumference and systolic blood pressure. The study reports these changes occurred with GlyNAC and not placebo.

• Older adults (open-label trial with withdrawal, 24 weeks + 12-week withdrawal): In 8 older adults, 24 weeks of GlyNAC “corrected” RBC GSH deficiency, oxidative stress, and mitochondrial dysfunction and improved inflammation, endothelial dysfunction, insulin resistance, genomic damage, cognition, strength, gait speed, exercise capacity, and reduced body fat and waist circumference. Importantly, benefits declined after 12 weeks of stopping, supporting an on-supplement effect but also showing durability may be limited without continued use.

• Longevity (mouse study): In C57BL/6J mice, GlyNAC supplementation increased lifespan by 24% versus controls and improved/corrected multiple age-associated defects (GSH synthesis/levels, oxidative stress, mitochondrial dysfunction, mitophagy/nutrient sensing abnormalities, genomic damage) in heart, liver, and kidneys. This is proof-of-concept for lifespan extension in mice, but it is not direct evidence of lifespan effects in humans.

• Age-associated cognitive decline (mouse study): In old mice, 8 weeks of GlyNAC improved/corrected brain GSH deficiency, oxidative stress, mitochondrial energetics defects, autophagy/mitophagy abnormalities, glucose transporter changes, inflammation, genomic damage, and neurotrophic factors, and it reversed cognitive impairment relative to old controls.

• Spinal cord injury (rat studies): GlyNAC (200 mg/kg by gavage for 4 weeks) improved BBB locomotor scores over weeks 1–8, supported body weight recovery, and showed some sensory improvement; it increased spinal cord glutathione and superoxide dismutase and decreased malondialdehyde (oxidative damage marker). Separate work found GlyNAC improved motor outcomes and muscle structure/function, and that GlyNAC + treadmill training was more effective than either alone for voluntary motor recovery. These are animal data and do not establish efficacy in humans with SCI.

• COVID-19: The provided COVID-19 abstract reports severe GSH deficiency and elevated oxidative stress/damage in hospitalized patients (worse with age), but it does not test GlyNAC as a treatment; therefore, efficacy for COVID-19 cannot be concluded from these studies.

• Type 2 diabetes: The provided T2D abstract is incomplete and does not provide outcomes; efficacy for T2D cannot be determined from the text shown.

Overall, the strongest human evidence in the studies reviewed here is for improving multiple aging-related biochemical and functional outcomes in older adults, including in a placebo-controlled randomized trial. Evidence for disease treatment beyond aging-related decline is largely preclinical (mice/rats) or observational (COVID-19 biomarker study).

3. What health benefits does it have?

• Raises/corrects glutathione status: Corrected RBC GSH deficiency in older adults (open-label trial) and improved GSH deficiency in the placebo-controlled trial; also improved GSH-related outcomes in multiple mouse/rat tissues.

• Reduces oxidative stress and oxidative damage: Improved oxidative stress markers in older adults in both clinical studies; decreased malondialdehyde and increased antioxidant capacity markers in SCI rats; improved oxidative stress and genomic damage outcomes in mice.

• Improves mitochondrial function/energetics: Improved mitochondrial dysfunction and mitochondrial fuel/fatty-acid oxidation in older adults; improved mitochondrial energetics in brains of old mice; improved mitochondrial-related aging defects in mouse organs.

• Metabolic benefits: Improved insulin resistance in older adults (both clinical trials). The placebo-controlled trial also reports improvements in waist circumference and systolic blood pressure; the open-label trial reports reduced body fat and waist circumference.

• Vascular/endothelial and inflammatory benefits: Improved endothelial dysfunction and inflammation in older adults (both clinical trials).

• Physical function benefits in older adults: Improvements reported in gait speed, muscle strength, and 6-minute walk/exercise capacity in both clinical trials.

• Cognitive benefits: Improved cognition in older adults (open-label trial) and reversed age-associated cognitive decline in old mice.

• Potential longevity/healthspan benefit (preclinical): 24% longer lifespan in supplemented mice, with broad improvements in age-associated cellular defects (mouse study).

• SCI recovery benefits (preclinical): Improved motor recovery and reduced muscle atrophy markers in SCI rats; additive benefit when combined with treadmill training in one rat study.

4. Does it have any downsides or side effects?

• Tolerability/safety in the provided human trials: The placebo-controlled randomized trial reports GlyNAC for 16 weeks was “safe and well-tolerated.” The 36-week open-label study reports 24 weeks of supplementation was “well tolerated.” The studies do not list specific adverse events or lab abnormalities.

• Benefits may require continued use: In the open-label trial, improvements declined after 12 weeks of withdrawal, suggesting effects may not persist once supplementation stops.

• Evidence limitations relevant to risk assessment: The studies reviewed here do not detail side-effect rates, rare adverse events, interactions, or risks in specific populations (e.g., kidney disease, asthma, anticoagulant use). Therefore, conclusions about downsides are limited to “well tolerated” in small studies and cannot exclude uncommon or long-term risks.

5. Is it beneficial or harmful for any genetic variations (pharmacogenomics)?

The studies reviewed here do not report pharmacogenomic analyses, genotype-stratified outcomes, or specific genetic variants that predict benefit or harm from GlyNAC (glycine + N-acetylcysteine).

• What can be inferred (with caution): The mechanistic focus across studies is restoration of glutathione availability and reduction of oxidative stress/mitochondrial dysfunction. This suggests that variants affecting glutathione synthesis/turnover or oxidative stress pathways could plausibly influence response, but this is not tested in the studies and should be considered speculative.

• Bottom line: No direct evidence in the provided research summaries that GlyNAC is specifically beneficial or harmful for particular genetic variants; dedicated pharmacogenomic studies would be needed.

References

1. Supplementing Glycine and N-Acetylcysteine (GlyNAC) in Older Adults Improves Glutathione Deficiency, Oxidative Stress, Mitochondrial Dysfunction, Inflammation, Physical Function, and Aging Hallmarks: A Randomized Clinical Trial.
   Premranjan Kumar, Chun Liu, James Suliburk, Jean W Hsu, Raja Muthupillai, Farook Jahoor, Charles G Minard, George E Taffet, Rajagopal V Sekhar (2023) - The journals of gerontology. Series A, Biological sciences and medical sciences
2. Glycine and N-acetylcysteine (GlyNAC) supplementation in older adults improves glutathione deficiency, oxidative stress, mitochondrial dysfunction, inflammation, insulin resistance, endothelial dysfunction, genotoxicity, muscle strength, and cognition: Results of a pilot clinical trial.
   Premranjan Kumar, Chun Liu, Jean W Hsu, Shaji Chacko, Charles Minard, Farook Jahoor, Rajagopal V Sekhar (2021) - Clinical and translational medicine
3. GlyNAC (Glycine and N-Acetylcysteine) Supplementation in Mice Increases Length of Life by Correcting Glutathione Deficiency, Oxidative Stress, Mitochondrial Dysfunction, Abnormalities in Mitophagy and Nutrient Sensing, and Genomic Damage.
   Premranjan Kumar, Ob W Osahon, Rajagopal V Sekhar (2022) - Nutrients
4. Severe Glutathione Deficiency, Oxidative Stress and Oxidant Damage in Adults Hospitalized with COVID-19: Implications for GlyNAC (Glycine and
   Premranjan Kumar, Ob Osahon, David B Vides, Nicola Hanania, Charles G Minard, Rajagopal V Sekhar (2021) - Antioxidants (Basel, Switzerland)
5. Mitochondria as Nutritional Targets to Maintain Muscle Health and Physical Function During Ageing.
   Sophie C Broome, Jamie Whitfield, Leonidas G Karagounis, John A Hawley (2024) - Sports medicine (Auckland, N.Z.)
6. The Effect of Glycine and N-Acetylcysteine on Oxidative Stress in the Spinal Cord and Skeletal Muscle After Spinal Cord Injury.
   Xin Xu, Chun-Jia Zhang, Zuliyaer Talifu, Wu-Bo Liu, Ze-Hui Li, Xiao-Xin Wang, Hua-Yong Du, Han Ke, De-Gang Yang, Feng Gao, Liang-Jie Du, Yan Yu, Ying-Li Jing, Jian-Jun Li (2024) - Inflammation
7. GlyNAC (Glycine and N-Acetylcysteine) Supplementation in Old Mice Improves Brain Glutathione Deficiency, Oxidative Stress, Glucose Uptake, Mitochondrial Dysfunction, Genomic Damage, Inflammation and Neurotrophic Factors to Reverse Age-Associated Cognitive Decline: Implications for Improving Brain Health in Aging.
   Premranjan Kumar, Ob W Osahon, Rajagopal V Sekhar (2023) - Antioxidants (Basel, Switzerland)
8. Glycine and N-Acetylcysteine (GlyNAC) Combined with Body Weight Support Treadmill Training Improved Spinal Cord and Skeletal Muscle Structure and Function in Rats with Spinal Cord Injury.
   Xin Xu, Hua-Yong Du, Zuliyaer Talifu, Chun-Jia Zhang, Ze-Hui Li, Wu-Bo Liu, Yi-Xiong Liang, Xu-Luan Xu, Jin-Ming Zhang, De-Gang Yang, Feng Gao, Liang-Jie Du, Yan Yu, Ying-Li Jing, Jian-Jun Li (2023) - Nutrients

This article summarizes published research for educational purposes. It is not medical advice. Talk to your doctor before starting, stopping, or changing any supplement or medication.