How Much Omega-3 Do You Need to Raise Your Omega-3 Index?

This scoping review pulled together 58 studies to answer a practical question: how much EPA and DHA does it actually take to raise the omega-3 index (O3i), a blood marker reflecting long-term omega-3 status? Most people studied started with a low O3i, typically between 3% and 6%, well under the 8% level linked to better cardiovascular outcomes in prior research.

Across the studies, eating fish alone rarely got people to target levels, and compliance with fish-based protocols was often poor. Supplements combining EPA and DHA, or DHA alone, were the most effective at raising O3i, especially at doses above 1,000 mg per day sustained for 12 weeks or longer. Supplements in triglyceride form appeared to be absorbed better than ethyl ester forms, making them more effective at the same dose. Other omega-3 sources like ALA or SDA from plant oils (flaxseed, soybean, echium) showed little to no meaningful effect on O3i.

The authors note that individual factors like starting O3i level, age, sex, and body weight play a role, but dose and supplement form appeared to matter most. Based on the pooled evidence, they suggest that 1,000–1,500 mg per day of combined EPA and DHA as triglycerides, taken for at least 12 weeks, is a reasonable target for improving O3i to 8% or above, though people starting from a very low baseline may need higher doses.