Insufflation of carbon dioxide gas into subcutaneous fat achieves a modest decrease in abdominal fat volume, according to the first randomised controlled trial on the treatment. However, the study, published in the Journal of the American Academy of Dermatology, also reports that the reductions were not maintained at six months.
In the sham-controlled study, 16 adults with a body mass index of 22-29kg/m2 received five weekly infusions of 1000cm3 of CO2 to one side of the abdomen, and five sham treatments to the contralateral side. Primary outcomes were ultrasound measurements of fat layer thickness and total circumference before and after treatment.
One week after the final treatment, ultrasound indicated less fat volume on the side treated with carboxytherapy (P=.011), but the benefit was not maintained at 28 weeks. Total circumference decreased nominally but not significantly at week 5 compared with baseline (P=.0697). Body weights did not change over the course of the study (P=1.00).
That the difference was not maintained at six months suggests the treatment stimulated a temporary metabolic process that reduced the size of fat cells without inducing cell death, said lead author, Dr Murad Alam, vice-chair of dermatology at Northwestern University Feinberg School of Medicine in the US.