Fish oil has long been considered one of the best supplements for heart and brain health, but a recent study is challenging this widespread belief. According to research published in *Cell Reports*, its effects are not the same for everyone, and in some cases, they may even be the opposite of what was expected. Supplements derived from fatty fish such as salmon and mackerel are rich in omega-3s, but scientists from the Medical University of South Carolina found that one of the key components, EPA, may slow down brain recovery after repeated injuries. According to the study, high levels of EPA in the brain are linked to a reduced ability to repair damage, and may also affect blood vessel function and promote the accumulation of tau protein, which is associated with diseases like Alzheimer's. On the other hand, another omega-3 fatty acid, DHA, appears to be more beneficial for the brain, as it integrates better into nerve cells and supports its functions. However, experts warn against jumping to conclusions. Fish oil may still be beneficial for many healthy individuals, but it is not a "one-size-fits-all solution." The key takeaway? What works for one person may not work for everyone, and in some cases, it could even have the opposite effect.