·       Older adults supplementing with the glutathione antioxidant precursor combination GlyNAC reduces cellular stress.
·      GlyNAC supplementation also improves physical functioning, muscle strength, inflammation, and cognition in older adults.

Getting older typically involves physical and cognitive decline as well as a diminished quality of life. At the root of this deterioration of physical fitness is damage to mitochondria, the cells powerhouse, and, ultimately, cells caused by oxidative stress — the buildup of harmful, oxygen-containing molecules and lack of antioxidants. So, scientists have been actively searching for ways to block oxidative stress to prevent age-related ailments.

Sekhar and colleagues from the Baylor College of Medicine published a pilot clinical trial in Clinical and Translational Medicine where they found that supplementing aged adults with GlyNAC improved physical function and cognition. They show that GlyNAC raises the levels of the antioxidant glutathione to lower cellular stress. Their findings offer promise in the search for methods to promote health and mitigate age-related physical deterioration.

“The overall findings of the current study are highly encouraging,” said Sekhar in a press release. “They suggest that GlyNAC supplementation could be a simple and viable method to promote and improve healthy aging in older adults.”

What is GlyNAC?

GlyNAC consists of two antioxidant precursors glycine and N-acetylcysteine. Cells use these precursors to synthesize glutathione, which is the most abundant antioxidant made by our own cells. When given to  older mice, GlyNAC enhances their mitochondrial function and improves metabolism. These promising rodent results prompted Sekhar and colleagues to see if these results would translate to human health.

GlyNAC Reduces Cellular Stress in Older Adults

To examine GlyNAC supplementation i in humans, the research team from the Baylor College of Medicine  supplemented eight older adults (five women, three men; 71–80 years) with 1.33 mmol/kg/day of glycine and .81 mmol/kg/day of N-acetylcysteine over the course of 24 weeks. Before looking into the possible effects of GlyNAC on human health, it was critical for the researchers to see if GlyNAC even raised glutathione levels in humans. When they looked at the glutathione levels in red blood cells, they found that the levels of  glutathione doubled. Not only that, they also found about a 75% decline in measures of cellular stress. But when they stopped GlyNAC supplementation, the buildup of glutathione reversed, indicating that GlyNAC increases glutathione levels and reduces cell stress.

(Kumar et al., 2021 | Clinical and Translational Medicine) Supplementing with a precursor combination raises antioxidant glutathione levels in cells and reduces cellular stress. The graph on the left shows antioxidant glutathione levels are higher in young adults in comparison to older adults but that GlyNAC precursor supplementation over the course of 24 weeks substantially increases glutathione levels. The graph on the right indicates that thiobarbituric acid reducing substance measurements, a measure of cellular stress, are significantly higher in older adults and that supplementing with GlyNAC glutathione antioxidant precursors significantly reduces their presence. These findings indicate that GlyNAC supplementation increases antioxidant glutathione levels and reduces cellular stress.

GlyNAC Improves Physical Performance and Cognition in Aged Adults

To see what effects increased glutathione levels and cell stress reductions have on physical performance, Sekhar and colleagues looked at walking speed and grip strength. GlyNAC supplementation improved older adult walking speed, matching the performance of young adults. GlyNAC also improved hand grip strength and exercise capacity. Stopping GlyNAC, though, led to a reversal in the physical benefits from supplementation.

Physical health goes hand-in-hand with cognitive abilities, so Sekhar and colleagues took a look at whether supplementing with GlyNAC also enhanced cognition. They found lower scores indicating cognition impairments on assessments of dementia and verbal fluency in older aged people. Twenty-four weeks of GlyNAC supplementation, though, significantly improved measures on cognitive functional assessments in these older adults, indicating that GlyNAC improves aged adult cognition.

(Kumar et al., 2021 | Clinical and Translational Medicine) Supplementing with the glutathione antioxidant precursor combination GlyNAC improves cognition in older adults. The table shows results of the Montreal Cognitive Assessment Test, a test used to detect dementia. Lower scores on the test can reveal mild cognitive dementia that may progress to dementia. Older adults scored significantly lower than young adults, but GlyNAC supplementation over 24 weeks substantially increased test scores. These findings indicate that supplementing older adults with GlyNAC improves cognitive capabilities.

“We speculate that GlyNAC represents three forces which could be operating simultaneously to result in such widespread improvements,” said Sekhar and colleagues in their publication in relation to how GlyNAC works.

Those three forces include the correction of the glutathione deficiency that helps against cellular stress and mitochondrial dysfunction. The second force could be that one of the glutathione precursors in GlyNAC, glycine, is important for normal brain function and may contribute to improved cognition. The third force relates to the other antioxidant precursor, N-acetylcysteine, which contributes to energy generation aside from contributing to glutathione formation.

What’s Next for GlyNAC?

The aging global population is in urgent need for new, health-promoting strategies. The study from Sekhar and colleagues presents findings suggesting that GlyNAC may provide a means to diminish cellular stress and improve strength, physical function, and cognition in aged adults. A limitation to the study comes from testing GlyNAC supplementation on a small number of people, so future studies should find whether similar results come from testing more people.

“I am particularly encouraged by the improvements in cognition and muscle strength,” Sekhar said. “Alzheimer’s disease and mild cognitive impairment (MCI) are serious medical conditions affecting memory in older people and leading to dementia, and there are no effective solutions for these disorders. We are exploring the possibility that GlyNAC could help with these conditions by conducting two pilot randomized clinical trials to test whether GlyNAC supplementation could improve defects linked to cognitive decline in Alzheimer’s disease and in MCI, and possibly improve cognitive function. We also have completed a randomized clinical trial on supplementing GlyNAC vs. placebo in older adults and those results will be forthcoming soon.”