A pilot study evaluating the anti‐aging benefits of a CO2‐emitting facial mask

Since 1936, injectable carboxytherapy has been used for the treatment of circulatory issues and lack of tissue trophism. In the last 25 years, it has been applied to aesthetic issues, especially those related to the signs and symptoms of skin aging. Presently, carboxytherapy is available as a combination of transcutaneous gels that produce CO2 with benefit for atrophic skin.


| INTRODUC TI ON
Carboxytherapy is a medical technique utilizing the injection of sterile carbon dioxide (CO 2 ) into the subdermal tissue as a method for the management of multiple disorders. Carboxytherapy has been used for skin rejuvenation, atrophic scars, striae distensae, cellulitefibrolipodystrophy adhesions after liposuction, and certain types of alopecia. Carboxytherapy originally referred to the subcutaneous injection of CO 2 to improve the microcirculation and thus promote wound-healing. 1 Table 1 summarizes the physiologic effects of CO 2 .
Carboxytherapy has been used in Argentina and France to treat peripheral arteriopathies, especially obliterative arteriopathy of the lower limb, and diabetic ulcers. When CO 2 is injected subcutaneously, it immediately diffuses at the cutaneous and muscular microcirculatory levels, increasing microcirculatory vasodilatation, and improving blood flow through a direct action on arteriole smooth muscle cells. 2 Via the Bohr effect, it also increases the tissue pO2 at the injection site. 3,4 The Bohr effect refers to a decrease in the affinity of hemoglobin for oxygen due to an increase in CO 2 , which means that extra oxygen is available to other tissues. 2,5 There is also a subsequent stimulation of fibroblasts and an increase in the quality of the extracellular matrix. 6,7 Carboxytherapy for antiaging purposes is a safe minimally invasive procedure that may be administered as intradermal and/ or subcutaneous microinjections of sterile purified carbon dioxide into different parts of the body for rejuvenation purposes. [8][9][10] Since 1932, the injection of carbon dioxide has therapeutically been used in balneotherapy predominantly for treating articular conditions, altered blood circulation of the lower limbs in ischemic diseases, cutaneous conditions in diabetic patients, systemic vascular diseases, and cardiac diseases. 11 These uses are based on the vasodilation effect induced. In a clinical trial by Nassar et al. on 60 patients with facial wrinkles, the efficacy of radiofrequency, intense pulsed light, and carboxytherapy was assessed and compared in facial rejuvenation. Patients received four sessions of each of these treatments with 3-to 4-week intervals, and the subjects were followed up 3 months after the last treatment. This study revealed that intense pulsed light was the most effective in facial rejuvenation, followed by carboxytherapy and radiofrequency, respectively. The results were confirmed by immunohistochemical assessment of matrix metalloproteinase-1 (MMP1). 13 Further work by Oliveira et al., investigated the efficacy of carboxytherapy in managing skin laxity through histological assessment of collagen and elastin fibers in nine subjects who received treatment on the left side of infraumbilical region. After 60 days of treatment, the results demonstrated elastic fiber synthesis and improvement in collagen fiber morphology. 14 Medrano et al. evaluated the efficacy and subject satisfaction of carboxytherapy in the acceleration of wound healing after facial nano fractional radiofrequency treatment in nine subjects with photoaging. The study showed an improvement in photodamage, pigmentation, and wrinkles with significant improvement of erythema, dryness, edema, crusting, and healing after radiofrequency at 24 h. 15 Thus, carboxytherapy has a history of safety and efficacy for a variety of medical uses.

| TR ANS DERMAL C ARBOX Y THER APY
Carboxytherapy can also be administered transdermally through a new treatment option that provides carbon dioxide (CO 2 ) through the skin's superficial layers. Doppler providing evidence of the Bohr effect in vivo. 16 Leibaschoff and co-workers used video capillaroscopy to evaluate the effect of a CO 2 transdermal gel and found improved microcirculation comparable to the improvement in microcirculation observed after subcutaneous CO 2 injection. 17 This research examined the use of CO 2 transdermal, which is a new technology based on mixing two packets of ingredients. One packet contains butylene glycol, magnesium carbonate, hydrolyzed collagen, ceramides, botanical antioxidants (passiflora edulis fruit extract, pueraria thunbergiana root extract, chlorella vulgaris extract, aloe barbadensis leaf extract), and calcium carbonate while the second packet contains gluconolactone, squalene, butylene glycol, and water.
The gels are mixed with a plastic tongue depressor type applicator in a bowl and applied as to the entire face, including eyelids, for 45 min.
The mixing of the two packets initiates a chemical reaction resulting in the release of CO 2 on the skin surface, some of which may enter the skin. Magnesium carbonate is an inorganic salt that reacts with aqueous acids to release CO 2 and water. The gluconolactone may have a mild exfoliating effect on the skin surface. The increase in skin carbon dioxide release may increase skin blood flow, exposing the skin to increased oxygen levels, while the mask itself induces moisturization. 17 This creates an environment suitable for skin barrier repair. The application of the combination of gels is peeled or washed away with water after the treatment has been completed.

TA B L E 1 The Physiotherapeutic action of CO 2 .
• Increased flexibility and decreased firmness of collagen fibers at pH ≤6.5 • Reduction of divalent calcium ions • Decreased tonus of arteries and capillaries leading to vasodilatation • Increased blood flow to the injected site • Decreased blood pressure • Improved tissue drainage due to increased tissue perfusion and lymph circulation • Release of local growth factors resulting in promotion of angiogenesis, lipolysis, and skin regeneration • Dissociation of carbonic acid to H + and HCO 3 and subsequent formation of Ca (HCO 3 ) 2 , NaHCO 3 , and KHCO 3 Eventual reactional increase of pH (alkaline state) resulting in an analgesic and spasmolytic effect • Improved activity of nerve endings resulting in improved trophicity of the treated body site activated oxidation of fats in the fatty tissue The carboxy mask was examined for both 4 week short term benefits and 10 week longer term benefits in two studies.

| Method
The short term study was conducted for 28 days after one application of the facial mask for 1 h at baseline (CO2 Lift, Lumisque Skincare). 16 healthy female subjects with mild to moderate photoaging age 45-75 years without skin disease who were not pregnant or lactating were enrolled. The subjects were asked to use their own self-selected skincare products that they had used without problem for 14 days prior to study enrollment. Subject also were not allowed to get more than  There was a statistically significant investigator assessed improvement in luminosity, radiance, tactile roughness, visual roughness, and erythema at week 4 after using the face mask (p < 0.001). This improvement continued into week 10. At week 10, there was a 36% improvement in luminosity, a 33% improvement in radiance, a 35% improvement in tactile roughness, and a 38% improvement in visual roughness (p < 0.001). In addition, improvement was seen in firmness (16%, p = 0.001), sagging (9%, p = 0.023), and overall skin appearance (12%, p = 0.002) (Figure 1). The improvement in firmness and sagging was supported by the noninvasive elasticity measurements.

| DISCUSS ION
The CO 2 combination of gels that produce CO 2 is a topical variation on a well-known procedure called carboxytherapy, a term coined in F I G U R E 1 Investigator assessments. Sustained improvement in facial appearance was noted by the dermatologist investigator.

Investigator Assessments
1995. 14 Carboxytherapy involves the exposure of the skin and subcutaneous tissue to carbon dioxide, a colorless and odorless gas, through injection. 18 The technique was developed in France in 1932 with the original treatments carried out in heated carbonated water baths or with water-saturated CO 2 applied directly to the skin. The treatments progressed to the transcutaneous or subcutaneous infusion of CO 2 . Currently, carboxytherapy has been studied for aesthetic dermatology indications of skin rejuvenation, atrophic scars, striae distensae, cellulite, and alopecia. However, carboxytherapy has been used for the treatment of vasculopathies, lower limb ischemia, diabetic ulcers, Raynaud syndrome, and chronic venous ins ufficiency. 9,10,12,[19][20][21][22][23][24][25] In the skin, the CO 2 reacts with water producing carbonic acid that reduces the skin pH. This lower pH weakens the bonding of  to the statistically significant improvement in the dermatologist investigator's assessment of overall facial appearance in subjects using the study product for 10 weeks as compared to baseline.
Mask administered carboxytherapy can be conducted by the patient in the privacy of their own home. There is no need for medical supervision, as demonstrated by the studies conducted. The mask can be easily mixed to release CO 2 , put on the face, removed, and then disposed. No needles or source of CO 2 is required. Limited skill on the part of the user is necessary and the mask can be applied whenever desire to improve facial appearance.
The limitations of the studies are the small sample size and the fact that the treatment evaluations were not continued on beyond 10 weeks.

ACK N OWLED G M ENTS
This study was approved by the Allendale IRB, Old Lyme, CT.

CO N FLI C T O F I NTER E S T S TATEM ENT
ZDD received a research grant from Lumisque to conduct the research detailed in this manuscript.

DATA AVA I L A B I L I T Y S TAT E M E N T
The data that support the findings of this study are available from the corresponding author upon reasonable request.

E TH I C S S TATEM ENT
This study was IRB approved by Allendale IRB and all subjects signed consent prior to the conduct of any research activities.