Fluid Containing Hyaluronic Acid, Gotu Kola Extract, and Glycerin Improves Skin Hydration and Skin Barrier Function in Healthy Women

Skin hydration is essential for maintaining healthy skin. Some skin moisturizers used both cosmetically and for skin disease, can negatively affect skin barrier function because they contain ingredients that are harmful to the skin. Hyaluronic acid (HA) is an anionic, nonsulfated glycosaminoglycan found in connective, epithelial, and neural tissue. The hydrating effects of HA and glycerin have been well documented, and HA is a naturally occurring component found in skin and connective tissue of the body. HA plays an important role in tissue repair in the skin and has an occlusive-forming mechanism of action. Abundant in flavonoids, amino acids, terpenoids, essential oils, and alkaloids, Gotu Kola (Centella Asiatica, Apiaceae) extract (CAE) reportedly exhibits anti-inflammatory, wound-healing, and re-epithelialization properties. These authors conducted a single-center, randomized, controlled, intra-subject, assessor-blinded study to evaluate and compare the effects of Jaluronius CS (JCS) fluid (Difa Cooper SpA; Caronno Pertusella, Italy), a fluid containing the moisturizing agents HA (1%) and glycerin (5%), Gotu kola meristem cell culture, and caprylic glycerides, on skin hydration and transepidermal water loss (TEWL), a measure of skin barrier function and rate of water lost through the skin.

Twenty female subjects, aged 40 ± 10 years, with healthy skin were enrolled in this 24-hour, intra-subject (right side versus left side), randomized, assessor-blinded, controlled study conducted at the Dermatologic Institute Dermig Milan in Milan, Italy. Subjects had normal skin absent from acute skin disease. Exclusion factors included dry skin (noted by skin hydration < 30 arbitrary units [AU]), significant skin disease, use of topical agents that altered skin integrity of upper arms, currently smoking, pregnancy or breastfeeding, reported use of systemic corticosteroids or cytostatic therapy within the last 30 days, and participating in any other ongoing studies. The primary outcomes were skin hydration and TEWL after a single application of JCS.

Under standardized conditions in a temperature- and humidity-controlled room, the subjects underwent measures of skin hydration and TEWL on the volar surface of the forearms, with the use of a corneometer and vapometer, at baseline and at 1, 8, and 24 hours after JCS was applied. On 1 forearm of each subject, 0.4 mL JCS was applied to an area measuring 5 cm by 15 cm (about 2 inches by 6 inches). The other forearm served as the control. The tested area was stripped 40 times with 15 mm clear tape to assess TEWL and skin barrier function after skin damage. The assessors were blinded to the treatment.

The authors report that skin hydration after 24 hours was 21% higher (P=0.001) in the JCS-treated area compared with the control area. A significant increase (P=0.0001) in skin hydration was observed in the JCS-treated areas at each time point compared with baseline as follows: 59% at 1 hour, 48% at 8 hours, and 29% at 24 hours. In the control areas, no significant changes in skin hydration occurred at any time point compared with baseline. The authors note that, because CAE inhibits HA’s enzymatic activity as elucidated in previous studies, it could potentially prolong HA’s hydrating duration of action when used concomitantly.

After 24 hours, TEWL was lower in JCS-treated areas compared with the control areas (P=0.049). Compared with baseline, JCS significantly reduced post-stripping TEWL (P=0.001) as follows: by 52% at 1 hour, by 32% at 8 hours, and by 48% at 24 hours. TEWL was not reduced in the control areas at any time point compared with baseline.

Present in both dermis and epidermis, HA plays a role in epidermal barrier function and hydration, hastens the re-epithelialization process, and exhibits free radical scavenging activity. “[T]he hydrating action of HA in this formulation [JCS] could be prolonged over the time, thanks to the inhibition activity of hyaluronidase present in the CAE explaining the long-lasting moisturizing effect we observed in this study,” write the authors.

The authors conclude that a “single daily application of JCS fluid containing HA, glycerin and CAE induced a long-lasting (up to 24 hours) hydrating and moisturizing effect, improving at the same time the skin barrier function in healthy women.” The main limitation of this study was the fact that it was not a double-blinded study.

The study was supported by Difa Cooper SpA, an Industrial Farmaceutica Cantabria company that provided the test product. Author M. Milani is Difa Cooper’s medical director, and author A. Sparavigna received an unrestricted grant from Difa Cooper to conduct this trial.

Resource:

Milani M, Sparavigna A. The 24-hour skin hydration and barrier function effects of a hyaluronic 1%, glycerin 5%, and Centella Asiatica stem cells extract moisturizing fluid: an intra-subject, randomized, assessor-blinded study. Clin Cosmet Investig Dermatol. 2017;10:311-315.

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