Docosahexaenoic acid (DHA) is an omega-3 fatty acid commonly found in fish oil and algal oil supplements. Its use for lowering elevated triglyceride levels is supported by substantial scientific evidence. Several randomized controlled trials and meta-analyses have demonstrated that supplementation with omega-3 fatty acids, particularly eicosapentaenoic acid (EPA) and DHA, can significantly reduce serum triglyceride concentrations in individuals with hypertriglyceridemia. The mechanism involves the inhibition of hepatic very low-density lipoprotein (VLDL) triglyceride synthesis and increased clearance of triglyceride-rich particles.

The American Heart Association and other major medical organizations recommend prescription-strength omega-3 fatty acids (which typically contain both EPA and DHA) for the management of high triglyceride levels. The effect size is dose-dependent, with reductions in triglycerides ranging from 15% to 30% at doses of 2-4 grams per day of combined EPA and DHA. While EPA and DHA both lower triglycerides, DHA may increase LDL cholesterol slightly, so the balance between these two fatty acids is often considered in clinical recommendations.

In summary, the use of DHA (usually in combination with EPA) to lower high triglycerides is scientifically validated, with a strong evidence base from human clinical trials and endorsements from relevant medical societies.