Source of Fish Oil

• The source of the fish oil can reveal the probable presence of toxins and other adulterants. Look for brands that state the species of fish the oil is extracted from. According to Omega 3 Salmon Oil Plus,"When a supplement label just says 'fish oil' or 'marine lipids,' they're hiding something and the product should NOT be considered."
  
  

Level of Purification

• According to Natural Product Insider, "several fish oil products sold in California failed to include label warnings for levels of PCBs (polychlorinated biphenyl compounds) found in the products by testing." When comparing fish oil, look for labels that specify the amount of contaminant in the product. Those that don't specify are likely hiding a high-contaminant presence in their product.
  
  

A Balance of All Eight Omega Fatty-Acids

• The highest benefit can be reaped from fish oil when all eight omega fatty acids are present. The most common include ALA, DHA and EPA. Look for a product that also contains DPA, ETA, HPA, ETA(3) and SDA. To assure all of the oil you are consuming is from omega fatty acids, add up the amount of oil provided by fatty acids and compare that to the total amount of oil in the product. If it comes up short, the other oil could be coming from anywhere.