Comparison of Fractional CO2 Laser Monotherapy and Its Combination With Either Topical Vitamin C or Topical Timolol in the Treatment of Post-Acne Erythema: A Split Face Study

Acne is very common, especially among young adults. After acne heals, some people are left with persistent red or pink marks, called post-acne erythema (PAE). These marks can last for several months and, in some people, may be associated with a higher risk of developing acne scars. PAE is more common in people with lighter skin. It is thought to happen because healing after acne can cause changes in the small blood vessels in the skin, making them wider and more visible. Skin irritation from some acne treatments may also contribute to the redness. There is currently no single treatment that is considered the best treatment for post-acne redness. Several treatments have shown benefits, including different types of lasers and light treatments, as well as topical creams or serums such as vitamin C, tranexamic acid, oxymetazoline, and brimonidine. Timolol, a medication that can narrow small blood vessels, has also recently shown promising results. Fractional CO₂ laser may help improve post-acne redness by stimulating skin healing and affecting the small blood vessels responsible for the redness. Other fractional lasers have also been shown to improve PAE. Vitamin C is a powerful antioxidant that can help protect and repair the skin. When applied directly to the skin, it may reduce inflammation, support collagen production, and promote healing. Studies have shown improvement in post-acne redness with topical vitamin C. Timolol is a medication that can cause narrowing of small blood vessels and may reduce the formation of new blood vessels. Because of these effects, it has recently been studied as a treatment for post-acne redness. Because there is still no established standard treatment for PAE, this study was designed to compare three approaches: fractional CO₂ laser alone, fractional CO₂ laser combined with vitamin C, and fractional CO₂ laser combined with timolol. The goal is to determine which approach provides the best improvement in post-acne redness.