Glycine + NAC (GlyNAC)
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Glycine + NAC (GlyNAC). Co-supplementation of glycine and N-acetylcysteine that restores glutathione in older adults and improves multiple hallmarks of aging.
How it works. Provides both rate-limiting substrates for de novo glutathione synthesis. NAC delivers cysteine for the γ-glutamylcysteine synthetase step; glycine completes the tripeptide via glutathione synthetase. Restoring GSH lowers oxidative stress, improves mitochondrial fatty-acid oxidation, normalizes insulin signaling, and reduces inflammatory cytokines (IL-6, TNF-α).
What the research supports. 5 graded claims. Strongest: Restores glutathione to youthful levels in older adults (moderate).
How much to take. Typical dose: Glycine 100 mg/kg/day + NAC 100 mg/kg/day, split into two daily doses with meals (≈7 g of each for a 70 kg adult). Split AM and PM with food to minimize GI effects.
Side effects and interactions. 3 medication interactions listed. Serious: Rare bronchospasm with NAC in asthmatics (more relevant to inhaled NAC).
Stacking. Pairs well with Magnesium glycinate, B-complex (B6, B12, folate), CoQ10 or PQQ. Avoid combining with Cisplatin and certain chemotherapy.
Common forms. Available as Combined GlyNAC capsules, Glycine powder + NAC capsules taken together, Free-form L-glycine + N-acetyl-L-cysteine.
Key studies. 14 studies cited. The strongest are listed with links to PubMed.
Community. Experiences from people who have tried Glycine + NAC (GlyNAC). Anecdotes are not medical advice.
Glycine + NAC (GlyNAC). Co-supplementation of glycine and N-acetylcysteine that restores glutathione in older adults and improves multiple hallmarks of aging.
What it is
GlyNAC is the combined oral supplementation of the two rate-limiting amino acid precursors of glutathione (GSH): glycine and N-acetylcysteine (a stable, absorbable form of cysteine). Glutathione is the body's principal intracellular antioxidant, and its concentration declines markedly with age — a deficit that GlyNAC has been shown in human trials to correct.
Also called
Food sources
Goals
How it works
Provides both rate-limiting substrates for de novo glutathione synthesis. NAC delivers cysteine for the γ-glutamylcysteine synthetase step; glycine completes the tripeptide via glutathione synthetase. Restoring GSH lowers oxidative stress, improves mitochondrial fatty-acid oxidation, normalizes insulin signaling, and reduces inflammatory cytokines (IL-6, TNF-α).
Pathways
- Glutathione (GSH) de novo synthesis
- Mitochondrial fatty-acid β-oxidation
- Redox / Nrf2 antioxidant response
- Insulin signaling and glucose disposal
Effects
- ↑Red blood cell and intracellular glutathione increases
- ↓Oxidative stress markers (8-OHdG, F2-isoprostanes, MDA) decreases
- +Mitochondrial fatty-acid oxidation and ATP output supports
- ↓Inflammatory cytokines (IL-6, TNF-α, hsCRP) decreases
- +Insulin sensitivity and fasting glucose supports
- ↓Genomic damage and senescence markers decreases
What the research supports
Strong: consistent results across large trials or meta-analyses. Moderate: several trials, mostly positive. Limited: small or mixed studies. Preclinical: animal or cell research only.
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Side effects & interactions
Common side effects
- Mild GI upset (bloating, loose stools)
- Sulfur-like odor from NAC
- Transient headache at higher doses
Serious
- Rare bronchospasm with NAC in asthmatics (more relevant to inhaled NAC)
Medication interactions
NAC potentiates vasodilation and may cause hypotension/headache.
Reduces NAC absorption — separate by ≥2 h.
Additive lowering of blood pressure possible.
Check any supplement–medication combination with your pharmacist before starting.
Combines with
Pairs well
- Magnesium glycinateAdditional glycine delivery and improved sleep quality during the protocol.
- B-complex (B6, B12, folate)Supports methionine/transsulfuration cycle that feeds cysteine availability.
- CoQ10 or PQQComplementary mitochondrial support alongside GSH restoration.
Avoid combining
- Cisplatin and certain chemotherapyAntioxidants may blunt cytotoxic efficacy — coordinate with oncologist.
Common forms
- Combined GlyNAC capsules
- Glycine powder + NAC capsules taken together
- Free-form L-glycine + N-acetyl-L-cysteine
Key studies
14 studies cited in total.
Opens current human and preclinical literature matching Glycine + NAC (GlyNAC) and "Restores glutathione to youthful levels in older adults". Filter by RCT, meta-analysis, or year on the results page.
Opens current human and preclinical literature matching Glycine + NAC (GlyNAC) and "Improves mitochondrial function and physical performance". Filter by RCT, meta-analysis, or year on the results page.
Opens current human and preclinical literature matching Glycine + NAC (GlyNAC) and "Lowers oxidative stress, inflammation, and insulin resistance markers". Filter by RCT, meta-analysis, or year on the results page.
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