Moisturizing Effectiveness Evaluation of Different Molecular Weight Hyaluronic Acid ( Jan.2016) Daubing cosmetics creams added with different molecular weight HA to left and right interior forearm, applying Corneometer method and TEWL method (Trans-Epidermal Water Loss ) testing the change condition of skin water content and skin water loss before and after daubing. Comparing moisturizing effectiveness of different molecular weight HA in cosmetics. I. Material 1. Experiment material: Oligo HA (MW 4400,Batch No. HA150515) HA-300kDa (MW 300kDa, Batch No. HA150531) HA-1670kDa (MW 1670kDa, Batch No. HA151111) Above HA are all produced by Shandong Galaxy Bio-Tech Co.,Ltd. 2. Apparatus: Corneometer CM 825 Tewanmeter TM300 II. Experiment Method 1. Experiment object
Standard age of object is 30-50, excluding pregnant and suckling period women, allergic body or be allergic on this cosmetic; excluding people with disease on heart and cerebral vessels, liver, kidney, hemopoietic system and psychiatric history; excluding using cosmetics that related with tested function in short time, which can affect experiment result judgment. 2. Experiment Environment Temperature: 25 ± 1, relative humidity: 50 ± 5%. Effective volunteers 30 people. 3. Test method: Effect of different molecular weight HA on the skin moisture content, different molecular weight HA (concentration 0.1%) was added to cosmetic cream base formulation as experiments, HA-free cosmetic cream as a contrast, mark 4 4cm*2 test area in the left and right forearm, use 3.0 ± 0.1 mg / cm 2 in the test area evenly applied to the test area. Respectively using Corneometer CM825 and Tewanmeter TM300 measuring 1h, 2h, 4h, 6h, 8h a region and ck region of skin moisture and skin moisture loss, comparing the difference between the molecular weight of skin moisturizing effect.
III. Experimental results 1. HA moisturizing effect comparison of different molecular weight in cosmetics Adding different molecular weight from figure 1 skin moisture content data analysis shows that: skin moisture content decreasing while HA molecular weight increasing. Oligo HA has the strongest effect of increasing skin moisture content, applying oligo HA to the skin surface can quickly penetrate into the deep skin to lock skin moisture, increase skin moisture, which playing a good moisturizing effect. Figure 1 Skin moisture influence of different molecular weight HA 2. The influence of skin moisture loss from different molecular weight HA As shown in Figure 2, with the increase of molecular weight of HA, the
smaller the skin moisture loss. High molecular weight HA has the function of good film-forming, daub on the skin surface, can form a layer of waterproof breathable membrane, restrain the loss of skin moisture, so the high molecular weight HA has the best effect in preventing the skin from moisture loss. Figure2 The influence of skin water loss from different molecular weight HA 3. The influence of skin moisturizing effect from HA concentration The maximum adding amount of high molecular weight HA in cosmetics is 0.5%. Because of its high viscosity characteristics, high adding amount in cosmetics would produce sticky feeling in daubing, hard to be absorbed quickly by skin. The molecular weight of oligo HA is extremely small, it is not sticky even in high concentration, adding high concentration can also satisfy the cosmetic refreshing skin sensation. oligo HA moisture retention is concentration dependent, as shown in Figure 3, with the increase of oligo HA concentration, the duration of the
moisturizing effect growth, when the concentration is 0.5%, it still showed significant improvement of skin moisture content after 6hrs from daubing. Figure 3 Skin moisture influence of different concentration oligo HA From the analysis data in Figure 3, at a concentration of 0.1%, oligo HA reduce the loss of skin moisture effect is not obvious. When the concentration of oligo HA reached 0.5%, it has outstanding effect on reducing skin moisture loss. Figure 4 Skin water loss influence of different concentration oligo HA
4. Evaluation of the moisture effect of HA combination with oligo HA Add 0.1%HA and 0.1% oligo HA to cosmetic formulations, after daubing the samples 1h, 2h and 4h, the skin moisture content was increased significantly, the skin water loss was decreased significantly. The combination of oligo HA and HA can play a synergistic effect, showing a better moisturizing effect. Figure 5 Skin moisture influence of HA combined with oligo HA Figure 6 Skin water loss influence of HA combined with oligo HA
IV. Conclusion Hyaluronic acid has a good moisturizing skin function in cosmetics, and different molecular weight hyaluronic acid moisturizing effect is different. High molecular weight HA can form a layer of transparent water film on the surface of the skin to prevent water evaporation inside the skin so as to achieve moisturizing function. Oligo molecular weight HA has fundamental skin deep moisturizing function through transdermal absorption. Apply different molecular weight HA into formula could get better moisturizing effect and anti-aging, skin repair function, which has more extensive application prospect.