34 FORMULATING FOR MILDNESS
peak corresponding to retinol/retinaldehyde (dark blue line, two minutes) has a much higher signal in the tissue treated with the mixed retinyl esters than the tissue treated with retinyl palmitate. This result indicates that retinol esterified with mixed unsaturated fatty acids appears to have been more effectively hydrolyzed to retinol, and perhaps further metabolized to retinaldehyde, in the EpiDerm skin tissue model.
Clinical trial results confirm the efficacy of retinyl linoleate While the in vitro gene expression and permeation and metabolism results were encouraging, ultimately, claims are supported most strongly by clinical results. A clinical study was conducted to assess the efficacy of a formulated skin cream containing 0.1% retinyl linoleate over a 12-week period. Experts graded the panelists at baseline
and after 12 weeks of home use on a scale from 0 (very clear, no wrinkles or spots) to 9 (Extremely visible dark spots, severe wrinkles). Twenty-one subjects of diverse age and skin types completed the study. Overall, subjects were graded
as experiencing a 44% reduction in hyperpigmentation, 49% decrease in uneven skin tone, and 55% increase in skin radiance (Figure 3). The overall appearance of wrinkles was reduced by 48% while fine lines were reduced by 41%. Data from self-perception questionnaires show the test article performed highly favorably (>80%) in all questions asked. No adverse reactions were reported, supporting the low potential for irritation from retinyl linoleate. The clinical study substantiated the below
claims regarding the formulation containing 0.1% retinyl linoleate. ■ Reduced the appearance of dark spots ■ Brightens/illuminates the appearance of skin ■ Improves the appearance of uneven skin tone ■ Improves the feel of skin texture ■ Reduces the appearance of fine lines and wrinkles ■ Dermatologist approved
Conclusion Retinyl linoleate is a safe and effective ingredient for new formulations that has been proven effective at reducing keys signs of aging in a clinical study. Retinyl linoleate is one of the few retinoids that is listed on the Inventory of Existing Cosmetic Ingredients in China.8 Eastman GEM retinyl linoleate offers additional assurance to formulators and brands by using a sustainable manufacturing process and offering a high-purity ingredient that is stable and easy to formulate.
References 1. VKM. Norwegian Scientific Committee for Food Safety. 2013 Adverse local effects of retinol and retinyl esters in the skin. Document number 13-405-1. ISBN: 978-82- 8259-114-0
2. Smal C, Hubaux R, Salmon M, Clendennen S, PERSONAL CARE April 2023
Baseline (time 0)■ 12 weeks■ 5 Reduction
4.5 4
3.5 3
2.5 2
1.5 1
0.5 0
Fine Lines Wrinkles 12 weeks■
60 50 40 30 20 10 0
+55% +49% +44% -41% -48%
Even Skin tone
Skin Radiance
Hyperpigmentation
Figure 3: Visual grading of efficacy of a formulated skin cream containing 0.1% retinyl linoleate over a 12-week period
Matton R. Retinyl esters are not alike: an in vitro study. Personal Care magazine. Aug 2021
3. Corey, Dorogi, Meyers, Vargas. 1997. Cosmetic composition with a retinol fatty acid ester. US Patent 5,885,595
PC
4. Babamiri & Nassab. Cosmeceuticals: The Evidence Behind the Retinoids. Aesthetic Surgery Journal. 2010; 30(1) 74–77
5. Fisher GJ, Reddy AP, Datta SC, Kang S, Yi JY, Chambon P, Voorhees JJ. All-trans retinoic acid induces cellular retinol-binding protein in human skin in vivo. J. Invest. Dermatol. 1995 105(1):80-6
6. Gates RE, Mayfield C, Allred LE. Human neonatal keratinocytes have very high levels
of cellular vitamin A-binding proteins. J. Invest. Dermatol. 1987; 88(1):37-41
7. Pohl & Tomlinson. Classical pathways of gene regulation by retinoids. In: Methods in Enzymology. Elsevier. 2020; Volume 637
8. An ingredient must be listed on the Inventory of Existing Cosmetic Ingredients in China (IECIC). Retinyl linoleate is listed on the IECIC: China CosIng - Chinese Cosmetic Ingredient Regulatory Database. CSAR Annex 14: Eastman GEM Retinyl Linoleate has been submitted in the ‘Information Form of Recorded Company for the Safety Related Information of Raw Materials’. The NMPA has assigned the reporting code 006166-02756-8627
www.personalcaremagazine.com
% improvement
Visual Grading 0-9
Improvement
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