Eicosapentaenoic acid (EPA) is an omega-3 fatty acid found in oily fish such as salmon, herring, mackerel and sardines.  The body uses it to produce DHA, another essential fatty acid.  A review of literature by scientists from the university of Alberta in Canada concluded that EPA might prevent muscle deterioration in cancer patients.  It might work by preventing muscle protein breakdown, improving insulin sensitivity, increasing appetite, and enhancing the effects of chemotherapy.  They cited several studies showing that EPA supplements improved weight maintenance, reduced muscle loss, and decreased inflammation in cancer patients.  There is no evidence that EPA increases muscle mass in bodybuilders.  (British Journal of Cancer 105:  1469-1473, 2011)