Neem's strongest human evidence is in the mouth: rinses, pastes and chewing sticks cut plaque and gum inflammation about as well as standard products. Elsewhere, unrepeated trials touch blood sugar and ulcers. Leaf and bark preparations appear well tolerated for a few months; swallowed seed oil causes severe, sometimes fatal illness in infants and seed preparations block fertility in animals. (Full Review)
| Marker | Target | Why |
|---|---|---|
| Alanine aminotransferase | 10–26 U/L (men), 8–22 U/L (women) | Earliest signal of the liver injury seen in animal toxicity studies |
| Aspartate aminotransferase | 10–26 U/L | Confirms and contextualises any alanine aminotransferase rise |
| Fasting glucose | 75–86 mg/dL | Tracks the intended metabolic effect and flags additive hypoglycaemia |
| Glycated haemoglobin | 4.8–5.2% | Confirms whether the glucose effect is real over months, not day to day |
| Estimated glomerular filtration rate | >90 mL/min/1.73 m² | Kidney function is the second organ affected in animal high-dose studies |
| Complete blood count | Within reference, stable against own baseline | Detects the marrow and red cell changes reported in animal chronic dosing |
| Semen concentration and motility | >40 million/mL, >45% progressive motility | The only direct measure of the documented animal antifertility signal |
| International normalised ratio | 2.0–3.0 if on warfarin; otherwise 0.9–1.1 | Captures the CYP2C9 interaction risk directly |
Cadence: Liver and kidney markers at 6–8 weeks, then every 3–6 months; glucose markers at 12 weeks, then every 6 months. Seed oil or above-trial doses use the shorter interval.