The participants took either 0.8 to 4 grams of omega-3s or a placebo, which was often some sort of plant-based oil, daily for 3 to 18 months.

The participants who took omega-3s were almost 3 times more likely than the placebo group to show improved (reduced) liver fat on an ultrasound, but not on MRI (a more advanced imaging technique).

Omega-3s also improved gamma-glutamyltransferase by 5.4 IU/L, but not other liver enzymes (AST and ALT). There was no effect on other signs of liver damage like fibrosis.

Side effects like nausea and diarrhea were more common with omega-3s, though few studies tracked this closely.

The quality of the evidence was mixed, but generally reasonable..

Can omega-3s help shed some liver fat? Original paper