In the 1960s Denham Harman hypothesised the free radical theory of ageing, but was himself frustrated by his inability to prove it. Fifty years later the theory still remains unproven. Having recently won a prize for her presentation on this topic at the 2015 National Herbalists Association of Australasia (NHAA) Conference, Dr Janet Schloss takes us through why the molecules known as "antioxidants" do not actually operate as "free radical trappers" but instead function as chemical messengers to normalise DNA and other chemical signals in our body.