Antioxidants are pretty much they key ingredient in most Stark products as they are essential to help skin protect from environmental damage, and are beneficial to all skin types and concerns, especially aging gracefully, and soothing acne.
Simply put, they are ingredients that help slow the process of oxidation: the slow decay that unstable molecules do to literally everything (think of rust or a cut apple turning brown). Basically, oxidation takes place within the human body as a completely natural, but somewhat mitigatable, process that leads to disease and inflammation, and the same is true for your skin. Antioxidants neutralize the "scavenger", "free-radical", super-unstable molecules, making them unable to damage healthy cells while trying to pilfer the stability they crave (wow, sounds like a weird clingy, anxious relationship.)
Within the body, the best antioxidants come from a diet rich in fruits and vegetables, but on the body, ie your skin, you need to supplement with topical antioxidants. Your skin loves tons of antioxidants (it can handle supplementation better than the inside of your body, that prefers to get it from food rather than supplements, but that's a whole other topic I am not qualified to talk about!). Topical antioxidants have had a lot of studies behind them
Some of Stark's favourite antioxidants are ferulic acid (found in City and in Petrichor), vitamin C in City, Elderberry extract in City and Midnight, the seed oils we use (antioxidant level is a key factor to choice), and so on! Do you consider antioxidants when choosing your skincare?