The dichotomy of antioxidants and prooxidants is an old one; their imbalance within the human body is linked to oxidative stress, which in turn leads to many diseases and also the acceleration of the aging process. Although previously believed not to have any beneficial properties, prooxidants seem to have signalling and defence properties in our body, apart from many other important functions, which are also justly attributed to antioxidants. Furthermore, given the capacity of antioxidants to work as prooxidants and vice versa, the concentration of certain compounds in the human body seems to be the secret to maintain an optimum equilibrium.

In a time where populations have become more concerned with their well-being by eating healthier and practicing physical exercise to avoid early aging and prevent some illnesses, the role of antioxidants, both endogenous and exogenous, is increasing. Concomitantly, the role of prooxidants is also becoming more related to well-being, thus making it of utmost importance to define what the optimum equilibrium of antioxidants and prooxidants is in our body is as well as to determine their effects on health and aging.

The aim of this Special Issue is to improve knowledge concerning antioxidants, prooxidants, and their implications on health and aging. We welcome original and relevant research manuscripts focusing on either in vitro or in vivo research, as well as review articles.

Potential topics include but are not limited to the following:

• Mechanisms of action of antioxidants and prooxidants
• Production
• Neutralization
• Interaction with other molecules
• Roles of endogenous and exogenous antioxidants in health and aging
• Functions of prooxidants in the human body
• Antioxidant versus prooxidants
• Implications on aging
• Implications on health and diseases
• Oxidative stress
• The role of lifelong medications in the production of prooxidants
• Detection of antioxidants and prooxidant compounds
• Limitations and benefits of methodologies