Is eicosapentaenoic acid (EPA) omega 3 or that's just a acid that comes with a omega 3? Same question for docosahexaenoic acid (DHA).
Just want to know are both of those two acid omega 3 despite being different acids.
There exists a range of ω-3 acids.
Fatty acids are made of a chain of carbon atoms (generally linear), with a carboxylic acid at one end. Usually the carbon atoms are linked with a single-bond, but in unsaturated acids one or more of these are double-bonds. In order to describe the positioning of these double bonds, the carbon-atoms are numbered, starting either from the carboxylic acid end, also called the α-end, or from the methyl-end (the other end), which is called the ω-end. Therefore, an ω-3 acid is a fatty acid with a double-bond from carbon number 3 to 4, counted from the methyl/ω-end.
Fatty acids can have several double-bonds in its chain, making it a polyunsaturated acid. An example is Eicosapentaenoic acid, which has 5 double bonds. Edit: As pointed out in comments, it is the position of the first double-bond that determines if the acid is called an ω-3 acid. Likewise: if the first double bond is from carbon number 6 to 7, the acid is an ω-6 acid.