When carbon dioxide gas is injected into the subcutaneous tissue below the skin, it dilates blood vessels, which increases circulation and oxygen flow to the tissues.
The treatment is sometimes touted as a nonsurgical alternative to liposuction for fat reduction. It’s believed that the treatment shrinks fat cells (possibly by damaging the cell wall, which may release the triglycerides inside) but doesn’t kill and eliminate them, so they can expand again with time. The first randomized clinical trial, performed in 2018, found that fat reduction results were no longer visible after 28 weeks.
A small pilot study that consisted of eight weekly carboxytherapy sessions for cellulite reduction found it helpful. However, Dr. Mark Youssef, a physician in Santa Monica, California, says in a RealSelf Q&A that “many patients require more than eight treatments, especially for stubborn cellulite,” along with regular follow-up treatments to maintain results. Other cellulite treatments, such as the newly FDA-approved injectable Qwo, have more solid science to back up claims of results.
Minimizing dark under-eye circles is one of the most common applications of carboxytherapy, especially since poor circulation (which creates vascular pooling) is one of their main contributors.
“The lack of appropriate oxygenation to the lower eyelid skin allows the bluish cast to show through the thin skin,” creating the look of dark circles, explains Dr. Ajaya Kashyap, a plastic surgeon in New Delhi. “By injecting a small amount of carbon dioxide gas into the affected areas, blood flow is increased and improved capillary networks are formed, for longer-lasting circulatory benefit.”
However, if your dark circles are due to fat loss that creates hollows, carbon dioxide therapy won't be nearly as effective as dermal fillers or fat transfer.
Carboxytherapy for stretch marks and scars works by encouraging healing. “It restarts the healing process and restores the circulation to the scarred tissue to give it the best chance at healing,” says New York City physician Dr. Jamé Heskett in a RealSelf Q&A.
Some doctors say that combining carboxytherapy with platelet-rich plasma (PRP) injections and microneedling (also known as collagen induction therapy) can improve results.
