Glycine + NAC (GlyNAC) vs Milk Thistle (Silymarin)

Mechanism

Combination that restores glutathione synthesis. Age-related glutathione deficiency is driven by glycine and cysteine precursor depletion, not enzyme dysfunction. GlyNAC corrects oxidative stress, mitochondrial dysfunction, inflammation, and insulin resistance in older adults.

Contraindications

• Active stomach ulcer (NAC)
• Asthma (NAC may cause bronchospasm in rare cases)

Mechanism

Silymarin is a complex of flavonolignans (silybin A, silybin B, silychristin, silydianin, isosilybin) with silybin being the most active. Hepatoprotective mechanisms: stabilizes hepatocyte cell membranes by altering outer lipid layer composition (preventing toxin penetration), stimulates ribosomal RNA polymerase I (accelerating hepatocyte protein synthesis and regeneration), inhibits NF-kB and TNF-alpha (anti-inflammatory), scavenges free radicals (both ROS and RNS), promotes glutathione synthesis (increases intracellular GSH by 35%), and inhibits hepatic stellate cell activation (anti-fibrotic). Silybin also activates AMPK and enhances bile flow.

Standard Dosing

200-400mg silymarin daily (standardized to 70-80% silymarin)

Timing

With meals. Split doses for higher amounts. Phytosome form can be taken without food.

Cycle Duration

Cycle 8-12 weeks for liver support; ongoing at low dose for maintenance

Side Effects

• GI discomfort (mild laxative effect)
• Headache
• Allergic reactions (Asteraceae allergy)
• Rare: anaphylaxis

Contraindications

• Allergy to Asteraceae/Compositae family plants (ragweed, daisies, marigolds)
• Caution with hormone-sensitive conditions (weak estrogenic activity reported for some silymarin components)

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