Is Glycine and N-Acetylcysteine (GLY-NAC) effective?

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Last updated: March 14, 2025View editorial policy

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From the Guidelines

Glycine and N-Acetylcysteine (GLY-NAC) supplementation is effective in improving certain health conditions, particularly those related to oxidative stress and glutathione deficiency, as evidenced by recent studies 1. The combination of glycine and N-acetylcysteine has been shown to have synergistic effects in boosting glutathione production in the body, which is essential for neutralizing free radicals and reducing oxidative damage.

Key Findings

  • Research suggests that GLY-NAC may help improve insulin resistance, oxidative stress, mitochondrial function, and inflammation in older adults 1.
  • Some studies indicate benefits of GLY-NAC supplementation for improving muscle strength, cognitive function, and cellular aging markers 1.
  • The typical supplementation involves taking both glycine (approximately 0.8g/kg/day) and NAC (approximately 600-1800mg daily) together, as they work synergistically to boost glutathione production in the body.

Mechanism of Action

  • GLY-NAC works by providing the precursors needed for glutathione synthesis, which is the body's master antioxidant that helps neutralize free radicals and reduce oxidative damage 1.
  • N-acetylcysteine has been shown to reduce the viscosity of respiratory secretions and aid in the elimination of secretions in patients with COPD and chronic bronchitis 1.

Clinical Evidence

  • A network meta-analysis of 22 recent trials involving 2,621 patients with severe alcoholic hepatitis found that treatment with glucocorticoids alone or in combination with N-acetylcysteine reduced 28-day mortality 1.
  • A study of 1,006 patients with moderate to severe COPD found that oral NAC 600 mg twice daily reduced the rate of exacerbations by 22% compared to placebo 1.

Recommendations

  • GLY-NAC supplementation may be considered for patients with conditions related to oxidative stress and glutathione deficiency, such as older adults with insulin resistance, oxidative stress, and mitochondrial dysfunction 1.
  • Further research is needed to fully establish the effectiveness of GLY-NAC supplementation for specific medical conditions and to determine optimal dosing protocols.

From the Research

Effectiveness of Glycine and N-Acetylcysteine (GLY-NAC) Supplementation

  • GLY-NAC supplementation has been shown to improve glutathione deficiency, oxidative stress, and mitochondrial dysfunction in various studies 2, 3, 4, 5.
  • A randomized clinical trial found that GLY-NAC supplementation in older adults improved glutathione deficiency, oxidative stress, mitochondrial dysfunction, inflammation, and physical function 3.
  • A pilot clinical trial reported that GLY-NAC supplementation in older adults corrected glutathione deficiency, improved mitochondrial function, and lowered oxidative stress, inflammation, and insulin resistance 4.
  • Another study found that GLY-NAC supplementation improved impaired mitochondrial fuel oxidation and lowered insulin resistance in patients with type 2 diabetes 5.
  • N-acetylcysteine (NAC), a component of GLY-NAC, has also been shown to have antioxidant effects and potential as an epigenetic modulator in the treatment of liver diseases 6.

Key Benefits of GLY-NAC Supplementation

  • Improves glutathione deficiency and oxidative stress 2, 3, 4, 5
  • Enhances mitochondrial function and fuel oxidation 3, 4, 5
  • Lowers inflammation and insulin resistance 3, 4, 5
  • Improves physical function and cognitive decline 3, 4
  • May have potential in the treatment of liver diseases and type 2 diabetes 6, 5

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

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