The use of the word ‘antioxidant’ has become widespread in food science, nutrition and consumer language, having become associated with potential health benefits linked to consuming sources of antioxidants in our food supply. However, there is significant doubt about direct antioxidant effects on human health. This may partly relate to methodology used for assessing functionality and activity (both in food matrices and in human health) as well as how data is extrapolated with respect to health based on laboratory analyses. In this review, the purpose and impact of antioxidants in food systems and on human health will be discussed, along with highlighting the best current methodology for analysing antioxidant effects. Consideration will also be made with respect to recommendations of how antioxidant activity should be reported, with a focus on being both scientifically accurate as well as minimising the risk of unwarranted extrapolations of benefits which might mislead end consumers.