Open Time of Skin “Microchannels” and the “Golden Delivery Window” After Fractional CO₂ Laser Treatment

Date: 2025.10.17

Fractional CO₂ Laser Treatment Golden Delivery Window Microchannels

Fractional CO₂ laser treatment creates a dense array of microscopic channels in the skin. While these channels stimulate collagen remodeling, they also temporarily open pathways that enhance transdermal drug delivery, allowing active ingredients to penetrate deeper layers of the skin. Understanding the opening and closing timeline of these microchannels helps clinicians optimize the timing of post-treatment applications, thereby improving efficacy and reducing adverse effects.

Microchannel Closure Time

Studies have shown that the microchannels formed after CO₂ fractional laser treatment remain open for approximately 24 hours. During this period, the channels gradually become shallower and narrower as the skin rapidly heals—a process influenced by the laser energy used.

At 5 mJ, about 87% of channels remain open 1 hour after treatment, decreasing to 27% at 12 hours and 20% at 24 hours.
At 25 mJ, 100% of channels are open after 1 hour, 53% remain open after 12 hours, and 40% after 24 hours. By the second day, most channels have closed.

The “Golden Window” for Drug Delivery

The 24-hour post-laser period represents a golden window for laser-assisted transdermal drug delivery. During this time, applying agents such as epidermal growth factor (EGF), fibroblast growth factor (FGF), topical corticosteroids, or nutritional supplements like hyaluronic acid and collagen can significantly enhance treatment outcomes.

However, all pharmaceuticals and medical products used must comply with NMPA (National Medical Products Administration) regulations, and administration should strictly follow aseptic protocols to ensure safety and prevent infection.