A dietary fat, not a drug. Well established: lower blood fats and lower blood pressure. Low-mood benefit is limited to one of the two marine forms. Heart attack and stroke prevention stays unsettled. Regular use, particularly above about a gram daily, raises the rate of an irregular heart rhythm; digestive complaints and aftertaste are common and dose-related. (Full Review)
| Marker | Target | Why |
|---|---|---|
| Omega-3 Index | 8–11% of red blood cell fatty acids | The only direct read-out of whether the dose worked |
| Triglycerides | Below 80 mg/dL | Primary and most responsive benefit |
| LDL cholesterol | Below 80 mg/dL, lower with existing plaque | Detects the rise caused by docosahexaenoic-acid-rich products |
| Apolipoprotein B | Below 80 mg/dL, below 60 mg/dL with plaque | Counts atherogenic particles when LDL cholesterol and particle size both rise |
| High-sensitivity C-reactive protein | Below 1.0 mg/L | Tracks the inflammatory pathway omega-3 is proposed to act on |
| Blood pressure | Below 120/80 mmHg | Second most reliable benefit, and a check on additive hypotension |
| Resting heart rhythm | Regular rhythm, no atrial fibrillation | Screens for the principal documented risk |
| Glycated haemoglobin | Below 5.4% | Checks that the historical glucose concern is not materialising |
| Liver enzymes (alanine aminotransferase) | Below 25 U/L for men, below 20 U/L for women | Tracks the fatty liver benefit |
Cadence: Omega-3 Index at 4 months; lipids and apolipoprotein B at 8–12 weeks; then both every 6–12 months, blood pressure quarterly, rhythm annually over 60.