Curcumin is a substance originally found in turmeric with many interesting properties. In this study, curcumin and the analogue 3,5-dimethoxycurcumin were synthesized. The antioxidant activity of the two substances was compared in vitro, and it was found to be lower for the analogue. The purpose of the study was to investigate the potential medical use of 3,5-dimethoxycurcumin as an antioxidant against cancer and Alzheimer’s disease. In general, the results from clinical trials where antioxidants have been tested against those diseases have not been promising. Thus, the probability that 3,5-dimethoxycurcumin will be used as an antioxidant against age-related diseases is low. However, it might still have other properties that makes it a useful treatment.