The relationship between fish oil supplementation and blood pressure remains unclear despite widespread interest in its potential heart health benefits. While omega-3 fatty acids, found abundantly in fatty fish, are linked to lower triglycerides, evidence on whether fish oil meaningfully reduces blood pressure is mixed.
The Inconsistent Research Findings
Studies on fish oil’s impact on blood pressure yield inconsistent results. According to Lauren Hynicka, PharmD, BCPS, of the University of Maryland School of Pharmacy, “Some studies have shown that fish oil may help to lower blood pressure, and others have not.” A 2022 analysis indicates that consuming 2–3 grams of omega-3 fatty acids daily can lead to a modest blood pressure reduction, particularly in individuals with pre-existing hypertension. However, the benefit for those already managing blood pressure with medication remains uncertain. Michelle Routhenstein, MS, RD, CDCES, CDN, a cardiology dietitian at Entirely Nourished, notes that “Those with normal blood pressure usually experience little to no change… when taking fish oil.”
Dosage and Product Variability
The inconsistency in findings is partly due to the wide variability in fish oil products. Different supplements contain varying ratios of DHA and EPA—the two primary omega-3 fatty acids—and studies test a range of dosages. Dose appears to matter, with some levels showing an effect while others do not. Hynicka emphasizes, “It is possible that the dose of fish oil makes a difference in the effect seen on blood pressure, but the research is mixed.”
How Fish Oil Might Work
Although conclusive evidence is lacking, studies suggest that fish oil may promote blood vessel relaxation and widening, potentially improving blood flow and reducing inflammation. Omega-3s may also combat oxidative stress—a buildup of damaging free radicals linked to high blood pressure.
Caveats and Conclusions
The effect of fish oil on blood pressure is modest at best, and the supplement isn’t a substitute for prescribed blood pressure medication or lifestyle interventions. The inconsistent research and product variability mean that the benefits are not guaranteed. If you’re considering fish oil for blood pressure, discuss it with your healthcare provider to determine if it’s appropriate for your individual needs.
