So-called “high strength” claims on omega-3 supplements could be leaving shoppers paying a premium for products that contain “surprisingly low” levels of active ingredients compared to cheaper versions, according to a consumer group. found Superdrug, Morrisons and Sainsbury’s Omega 3 Fish Oil 1000mg supplements each contained 250mg of EPA and DHA combined despite their “high strength” labels. Similarly, Holland & Barrett’s High Strength Omega 3 Fish Oil 1500mg contained just 375mg, well below the 450mg daily advised dose. A Holland & Barrett spokeswoman said: “There is currently no legal or industry-wide definition of what constitutes a ‘high strength’ omega-3 fish oil supplement. “At Holland & Barrett, the term is used to help customers distinguish between the different strengths and formulations of omega-3 products within our range.