Chia seeds, like most plant-based sources of Omega-3 are mostly Omega-3 ALA and not the Omega-3 DHA or EPA found from fish or algae sources. The body needs to convert Omega-3 ALA into DHA or EPA and there are various other factors involved in the conversion.
https://livinginnaturalharmony.com/blog/2018/01/12/omega-3-c...