Big effect
Fish oil lowered depression scores by 10 points in an 8-week trial — but the study was small and other health markers like blood sugar and cholesterol didn't budge
This is one of the first controlled trials to show such a large effect on depression symptoms, but with only 57 participants and a clinical population, the result needs replication before it can be generalized.
In an 8-week randomized trial, people with major depressive disorder who took 600 mg of fish oil daily saw their depression scores drop by an average of 10 points on a standard clinical scale (the Hamilton Depression Rating Scale), compared to a placebo. Krill oil produced a similar 8.5-point drop. However, the study was small, and while anxiety and distress also improved, the supplements had no significant effect on triglycerides, fasting glucose, cholesterol, or HbA1c — meaning the benefits were limited to mood-related symptoms.
Where this fits in the evidence
This is among the first studies we've indexed on Fish Oil for Reduced Depression Symptoms — treat it as an early signal until more research accumulates.
The study
- Randomized Controlled Trial (RCT)
- n = 57
- 2025-07
- Journal of affective disorders
This is a plain-language summary of a research finding, not medical advice. Pillser surfaces research signals to help you decide what's worth investigating — always consult a qualified professional before changing what you take.