A low-cost, long-established blood-pressure medicine. Human evidence is strong for lowering blood pressure, for survival in heart failure and after a heart attack that weakens the heart's pumping, and for slowing kidney filtering loss where protein leaks into urine. Evidence for slowing aging is animal-only. Harms are well characterised and mostly manageable. (Full Review)
| Marker | Target | Why |
|---|---|---|
| Home blood pressure (seated, averaged) | 110–125 / 70–80 mmHg | Primary efficacy signal |
| Serum potassium | 4.0–4.5 mmol/L | Principal metabolic harm |
| Serum creatinine and estimated glomerular filtration rate | eGFR above 90 mL/min/1.73 m²; creatinine rise under 30% | Separates expected filtration dip from injury |
| Urine albumin-to-creatinine ratio | Below 10 mg/g | Tracks the kidney benefit |
| Serum sodium | 138–142 mmol/L | Catches over-diuresis amplifying hypotension |
| Complete blood count with differential (absolute neutrophil count) | Above 2.0 × 10⁹/L | Rare marrow effect, while reversible |
| Serum zinc | 90–110 µg/dL | Urinary zinc loss increases |
| Fasting glucose and HbA1c | Glucose 75–86 mg/dL; HbA1c 4.8–5.4% | Tracks the metabolic benefit |
| Plasma renin activity | No established target; change from own baseline | Confirms target engagement; flags non-adherence |
Cadence: Potassium and creatinine at one to two weeks, after each dose increase, at three months, then six- to twelve-monthly. Home blood pressure daily for a fortnight, then weekly. Blood counts monthly for three months in impaired filtration or autoimmune disease. Albumin-to-creatinine ratio and zinc annually.