Of the vitamins identified by the National Institutes of Health, all 13 are electroactive. Vitamins serve as enzymes and coenzymes in metabolic reactions. As catalysts and co-catalysts, vitamins neither provide energy nor serve as structural components of larger molecules. The formal potentials E0' for the vitamins near physiological pH are plotted on a potential axis [1] as shown in Figure 1. The potential axis provides perspective on the energetics of various species. For example, E0' for the four lipid soluble vitamins A, D, E, and K lie outside potential window for water at pH 7. Vitamin C and all the B vitamins are water soluble, with vitamins C and B12 near the middle of the water window. Review of the literature reveals the vitamins are grouped mechanistically as single electron transfer reagents (B3, B7, B2, C, and D), vitamins that can be both oxidized and reduced (B1, B5, B6, B9, and E), and vitamins that undergo two successive and distinct reductions (B12 and K). Mechanistically, vitamin A is most complex. The potential axis and voltammetric mechanisms provide tools to assess and compare various properties of the vitamins. This includes: Electrochemical stability in air, water, and acidAntioxidant characteristics that include interactions with reactive oxygen species (ROS)Electrochemical instability of vitamin pairsPossible cooperative interactions between vitamins in health and medicinePossible mechanisms for vitamin recycling in situ For electrochemical mechanisms that are composed of electron transfer steps (E) and chemical steps (C), the majority of the voltammetric responses are EC mechanisms of various types. For B1, B6, B7, and B9, the reduction of the vitamin is a simple electron transfer, E. Vitamin K voltammetry is EE.Vitamins B1, B9, B5, B6, and E can be reduced and oxidized. Disproportionation of the reduced and oxidized forms can regenerate the initial vitamin species.Vitamin C has a formal potential near the middle of the water window and undergoes ring opening on oxidation in an ECirrev process. With the lowest E0' for oxidation of a vitamin, vitamin C may serve to reduce superoxide, peroxyl, and hydroxyl radicals and thus mitigate effects of ROS. The thermodynamic (E0') and mechanistic (EC) characteristics of the 13 vitamins will be surveyed from the perspective of a potential axis to highlight the similarities and distinctions of these 13 electroactive and metabolically critical species. Reference [1] M. D. Lovander, J. D. Lyon, D. L. Parr IV, J. Wang, B. Parke, and J. Leddy, CRES3T Review—Electrochemical Properties of 13 Vitamins: A Critical Review and Assessment, Journal of The Electrochemical Society, 165 (2) G18-G49 (2018). Figure 1. Potential Axis with 13 Vitamins. From reference [1]. Figure 1