CLA is a fat from grazing animals, sold as a weight-loss supplement. It does what it is sold to do, but barely: body fat falls slightly, lean tissue rises less. Against this sits a metabolic cost — blood sugar rises, insulin sensitivity falls, blood fats drift unfavorably. The stronger health signals attach to grass-fed dairy, not the supplement. (Full Review)
| Marker | Target | Why |
|---|---|---|
| Fasting glucose | 75–86 mg/dL | Most reliably moved the wrong way by CLA |
| Fasting insulin | 2–5 µIU/mL | Detects lost insulin sensitivity early |
| HOMA-IR | Below 1.0 | Insulin resistance index CLA worsened |
| Glycated hemoglobin | 4.8–5.3% | Three-month average; shows if a rise persists |
| LDL cholesterol | Below 100 mg/dL | Tracks the lipid drift seen in long trials |
| HDL cholesterol | Above 55 mg/dL (men), above 60 mg/dL (women) | CLA lowered it in a controlled trial |
| Triglycerides | Below 80 mg/dL | Flags fat redirected to the liver |
| Lipoprotein(a) | Below 30 mg/dL (75 nmol/L) | Rose on 12 months of CLA; independent cardiovascular risk |
| ALT | Below 20 U/L (men), below 17 U/L (women) | Liver-specific; baseline for rare acute injury |
| AST | 10–26 U/L | Rose over 24 months of continuous use |
| High-sensitivity C-reactive protein | Below 0.5 mg/L | Doubled on purified trans-10, cis-12 CLA |
| Body fat percentage | No established target; the individual's own baseline | The outcome CLA is taken for; moves least |
Cadence: Full baseline; glucose and insulin at 4 and 12 weeks; lipids, liver enzymes and body composition at 12 weeks and 6 months; after the first year, every 6–12 months.