Are there any shelf-life issues with products containing DHA/EPA?

There is very little public information in the literature on the level of oxidation products present in such products when sold or after longer-term storage in the home. The quality of the oil, processing technologies, antioxidants present, other protections (such as encapsulation or micro-encapsulation), types of products being sold (supplements, enriched food products, etc.) can all influence the stability and oxidative status. Many years ago, Dr. Piche and colleagues from the University of Guelph showed that a bottled fish oil product used under domestic conditions could significantly increase the level of malondialdehyde (an oxidation product of omega-3 fatty acids) in the urine of subjects consuming it whereas this was not found with an encapsulated fish oil product.