Glycine and NAC Benefits: A Powerful Combination for Healthy Aging

By Dr. Alex Rinehart

• August 23, 2023
• Alexander Rinehart, DC, MS, CNS

Many scientists are working to find ways to help people age better and stay healthier as they get older. One new study has shown that combining glycine and NAC could be beneficial for many areas of cardiometabolic health (1).

Before diving into the details of the study, here’s what they’re capable of individually…

Glycine and NAC Benefits

Glycine: Not Just a Regular Amino Acid

People often think of Glycine as a common amino acid, but it does many things for our health:

• Better Sleep: Glycine can help us sleep better and deeper possibly by playing a role in how the body cools itself, which helps us fall asleep (2; 3; 4). Glycine is also an inhibitory neurotransmitter on its own, and it may work as a precursor to GABA, a neurotransmitter that also promotes relaxed activities in the body (5).
• Collagen Synthesis: Glycine is a part of collagen, which is important for our skin, healing wounds, and keeping our joints and muscles strong. Glycine supports collagen formation in the body (6).
• Mood Support: Because glycine is inhibitory to the brain and nervous system, it may help balance out the excitatory activity of glutamate and other neurotransmitters – leading to a more balanced mood, and potentially less anxiety (7).
• Metabolic Health: Glycine is not only deficient in those that are obese or insulin resistant, it can help regulate blood sugar levels (8; 9). Because of its role in collagen formation, a glycine deficiency can make it more difficult for tissues to heal from damage caused by high blood sugar.
• Digestion: Glycine is a relaxing neurotransmitter and can help aid in “rest and digest” body functions. Glycine aids in the production of bile salts, which help us digest food better and play roles in detoxification (10).
• Anti-Inflammatory Properties: Emerging research hints at glycine’s potential anti-inflammatory properties, which could have broad implications, from managing “hallmarks” of aging, as well as chronic inflammation and auto-immune disorders (11). This may be related to its connection with glutathione synthesis, in which NAC is a precursor as well.

N-Acetylcysteine (NAC): A Broad Spectrum of Benefits

N-Acetylcysteine, commonly referred to as NAC, has a storied history in the scientific community, not only for its role when combined with glycine but also for its individual merits.

• Antioxidant Powerhouse: NAC is good at fighting against damage in our cells (12; 13). It helps make an important “master antioxidant” called glutathione which fights harmful substances in our body (14).
• Mucolytic Agent: Traditionally, NAC has been used as a mucolytic agent, assisting in breaking down mucus in the airways (15) This may make it a valuable tool in managing conditions like chronic bronchitis, cystic fibrosis, or helping out with a stuffed nose (16; 17).
• Neuroprotective Qualities: Like Glycine, NAC might help protect the brain. Studies suggest that NAC may have neuroprotective effects. It has been explored in the context of neurodegenerative diseases, such as Alzheimer’s and Parkinson’s, with some research suggesting its potential to slow down cognitive decline (18).
• Mental Health: An exciting avenue of research has been the use of NAC in managing certain psychiatric conditions and substance use disorders. Preliminary results indicate potential benefits for mood disorders, obsessive-compulsive disorders, schizophrenia, and even helping with addiction (19). The potential combined effects of glycine and NAC might be even more interesting in this regard.
• Liver Protection: NAC is occasionally used in the medical setting for acetaminophen (example: Tylenol) overdose due to its liver-protective properties. It can aid in replenishing glutathione, essential for neutralizing the harmful byproducts of acetaminophen metabolism (20). It’s found in many liver support formulas. NAC is one of my top choices for liver health and everyday wellness.

New Study on Glycine and NAC Benefits

The study looked at how Glycine and NAC (together called GlyNAC) affected signs of aging. 36 people took part. They looked at various health measures like oxidative stress and insulin resistance to blood pressure and body composition.

The research design was a randomized controlled study, where participants were administered either GlyNAC at a dose of 100 mg/kg/day or a placebo (alanine) at 200 mg/kg/day. The older adults underwent the regimen for 16 weeks, whereas the younger group for 2 weeks.

Assessments ranged from physical function tests, such as walking speed and grip strength, to markers indicating inflammation and oxidative stress. Additionally, they looked at body composition.

Key Outcomes of the Glycine and NAC Study

After 16 weeks of GlyNAC supplementation, older adults had:

• A significant rise in glutathione levels, soaring up by 164%
• A remarkable reduction in oxidative stress indicators, with a main marker improved by 72%.
• Improved physical function was evident from improved gait speed, grip strength, and sitting-to-standing test results.
• A 78% spike in fat-burning activity of the mitochondria. 
• A considerable improvement in insulin resistance by 64%
• Beneficial changes in inflammation markers (drop in IL-6, TNF-alpha, sICAM1, sVCAM1, and CRP), and a rise in anti-inflammatory IL-10.
• Decreased waist size and blood pressure

Interestingly, many of the older adults in the study reached levels seen in the younger adults.

Improvements spanned a broad spectrum, from cardiometabolic health to physical function making the combined supplementation an exciting area of clinical nutrition.