Antioxidants help to protect the skin from damage caused by environmental factors such as UV radiation and pollution. These factors can cause the production of free radicals, which can damage the skin's cells and lead to premature aging, pigmentation, and other skin problems.

Antioxidants work by neutralizing these free radicals and protecting the skin from further damage. They can also help to improve the overall health and appearance of the skin by promoting collagen production and reducing inflammation. 

There are many different antioxidant ingredients that can be effective in skincare products, but some of the most well-studied and widely used include:

• Vitamin C: Also known as ascorbic acid, vitamin C is a powerful antioxidant that can help to brighten the skin and reduce the appearance of dark spots. It also helps to boost collagen production, which can help to firm and plump the skin.
• Vitamin E: Also known as tocopherol, vitamin E is an antioxidant that can help to protect the skin from UV radiation and other environmental stressors. It also helps to moisturize the skin and reduce the appearance of fine lines and wrinkles.
• Resveratrol: It's a polyphenol antioxidant that is found in grapes, red wine, and certain berries. Resveratrol has been shown to protect the skin from UV damage, reduce inflammation, and improve skin elasticity.
• Ferulic Acid: It's an antioxidant found in plants like rice bran, oats, and apple that can increase the effectiveness of other antioxidants like vitamin C and E. It also helps to protect the skin from UV radiation and other environmental stressors.
• Coenzyme Q10: It's a naturally occurring antioxidant found in the body that can help to reduce the appearance of fine lines and wrinkles. It also helps to improve skin firmness and elasticity.
• Green Tea Extract: It's a powerful antioxidant that can help to soothe and calm the skin, reduce inflammation and redness, and protect the skin from environmental stressors.

It's important to note that the effectiveness of an antioxidant ingredient can vary depending on the product and how it is formulated. Additionally, the concentration of the ingredient also plays a role. So, it's always good to read the label and consult a skincare professional if you have any concerns.