Rosmarinic acid is a plant compound found in kitchen herbs such as rosemary and lemon balm, sold as a concentrated supplement for general health and longevity. It is a low-risk option with modest, mostly short-term signals rather than proven longevity benefits; the most consistent human findings are seasonal allergy relief and less fatigue during cancer treatment. Risks appear mild, but the evidence is thin and partly from extract makers. (Full Review)
| Marker | Target | Why |
|---|---|---|
| Thyroid-stimulating hormone (with free T4) | 0.5–2.5 mIU/L | Thyroid-signaling interference |
| Ferritin (with hemoglobin) | 50–150 ng/mL | Iron-absorption effect |
| ALT (with AST) | Below 25 U/L | Liver safety |
| eGFR | Above 90 mL/min/1.73 m² | Clearance of metabolites |
| Fasting glucose | 75–90 mg/dL | Additive glucose lowering; only needed with glucose-lowering drugs |
| Free testosterone (with total testosterone, SHBG) | No established target; track change from own baseline | Anti-androgenic effect; for long-term spearmint users |
| hs-CRP | Below 1.0 mg/L | Anti-inflammatory effect |
Cadence: Baseline before starting; repeat thyroid-stimulating hormone, ferritin and any goal-specific marker at 3 months, then every 6–12 months while use continues; glucose weekly during the first month on diabetes drugs.