The original manufactured copy of human insulin: fast enough to cover a meal, gone within a working day, and priced far below the engineered versions that replaced it. Good blood sugar control with it protects eyes, nerves and kidneys. Low blood sugar is the defining hazard, weight gain is expected, and long-term effects on aging are unresolved. (Full Review)
| Marker | Target | Why |
|---|---|---|
| HbA1c | 6.0–6.5% in adults under 65; 7.0–7.5% past 65 | Average blood sugar over ~3 months |
| Fasting insulin | Under 5 µIU/mL endogenously; not interpretable once injecting | Quantifies the insulin burden that longevity practitioners aim to minimize |
| C-peptide (fasting) | Above 0.6 ng/mL indicates useful residual output | Shows how much insulin the pancreas still makes |
| Time in range (continuous glucose monitoring) | Above 70% of readings between 70–180 mg/dL | The most actionable day-to-day measure of control |
| Serum potassium | 4.0–4.5 mmol/L | Insulin drives potassium into cells; depletion causes arrhythmias |
| eGFR | Above 80 mL/min/1.73 m² | Falling filtration prolongs insulin action and raises overshoot risk |
| Body weight and waist circumference | Waist under 94 cm (men) / 80 cm (women); weight stable within 2 kg | Detects the fat gain that insulin predictably causes |
| Fasting lipid panel | Triglycerides under 100 mg/dL; HDL above 50 mg/dL | Insulin suppresses fat breakdown and shifts the lipid pattern |
Cadence: Glucose weekly during titration; HbA1c at three months, then every three to six months; potassium and creatinine at three months, then annually; weight monthly; injection sites every visit.