Glycine is a cheap, well-tolerated amino acid the body makes but may run short of with age. Its clearest human benefit is better, faster sleep; it also supplies a building block for the body's main antioxidant. Effects on blood sugar, inflammation, connective tissue, and heart health remain promising but unproven. (Full Review)
| Marker | Target | Why |
|---|---|---|
| Fasting glucose | 70–85 mg/dL | Tracks glucose metabolism, a plausible glycine target |
| Hemoglobin A1c (HbA1c) | < 5.4% | Three-month blood-sugar average |
| hs-CRP | < 1.0 mg/L | General marker of inflammation |
| Triglycerides | < 80 mg/dL | Metabolic-health marker linked to low glycine |
| ALT / AST | ALT < 25 U/L (women), < 30 U/L (men) | Screens liver health relevant to fatty-liver goals |
| Creatinine and eGFR | eGFR > 90 mL/min/1.73m² | Confirms kidney capacity before higher doses |
| Homocysteine | 5–7 µmol/L | Reflects one-carbon metabolism that glycine feeds |
| Glutathione (red-blood-cell) | Lab-specific; higher within range preferred | Direct readout of the antioxidant glycine helps build |
Cadence: ~3 months after starting, then every 6–12 months (sooner if kidney function is a concern)