Risk of Side Effects from Ingestion of Omega-3 Fatty Acids, Per Dosage
| Up to 1 g/day | 1 to 3 g/day | More than 3g/day | |
| Fishy Aftertaste | Low | Moderate | Likely |
| Gastrointestinal Upset | Very low | Moderate | Moderate |
The Most Common Side Effect of Fish Oil is Fishy Aftertaste
- In the GISSI Prevention study, which provided 850 mg of Omega-3 fatty acids per day for 3.5 years,
- 3.8% of patients discontinued taking their supplements compared with 2.1 taking Vit E
- Gastrointestinal disturbance and nausea were the most commonly reported side effects, with 4.9% and 1.4% reported, respectively, compared with 2.9% and 0.4% in the Vit E group
- When 12 capsules containing 6g of Omega-3 fatty acids were fed to 41 patients for 2.4 years, three patients (7% of patients) dropped from the study claiming intolerance to the capsules
- In a 6-month trial providing 275 patients with 6.9g of EPA + DHA in 10 capsules daily, there was no difference between fish oil and corn oil control groups for any adverse events/
- Gastrointestinal upset was reported by 8% of the latter and 7% of the former.
