- in a recent clinical study it was shown that very aged sun protected buttock skin (76-year old, on average) responded to 0.4% retinol treatment for only 7 days with increased epidermis epidermal thickness, improve skin blood vessel function, and increase elastin, collagen output by fibroblasts in the dermis, leading to improved firmness and elasticity.
- The study concludes that irritating tretinoin/retinoic acid are not necessary and simple retinol is equally effective in fighting skin ageing, even in older people and even in thick skin, such as buttock skin. Results in thinner facial skin should be even more pronounced, as smaller amounts of actives are needed for facial skin and absorption is much higher.
- Source: Molecular basis of retinol anti-aging properties in naturally aged human skin in vivo.
- Abstract: OBJECTIVE: Retinoic acid has been shown to improve the aged-appearing skin. However, less is known about the anti-aging effects of retinol (ROL, vitamin A), a precursor of retinoic acid, in aged human skin in vivo. This study aimed to investigate the molecular basis of retinol anti-aging properties in naturally aged human skin in vivo. METHODS: Sun-protected buttock skin (76±6 years old, n=12) was topically treated with 0.4% ROL and its vehicle for seven days. The effects of topical ROL on skin epidermis and dermis were evaluated by immunohistochemistry, in situ hybridization, Northern analysis, real-time RT-PCR, and Western analysis. Collagen fibrils nanoscale structure and surface topology were analysed by atomic force microscopy. RESULTS: Topical ROL shows remarkable anti-aging effects through three major types of skin cells: epidermal keratinocytes, dermal endothelial cells and fibroblasts. Topical ROL significantly increased epidermal thickness by stimulating keratinocytes proliferation and upregulation of c-Jun transcription factor. In addition to epidermal changes, topical ROL significantly improved dermal extracellular matrix (ECM) microenvironment; increasing dermal vascularity by stimulating endothelial cells proliferation and ECM production (type I collagen, fibronectin, and elastin) by activating dermal fibroblasts. Topical ROL also stimulates TGF-β/CTGF pathway, the major regulator of ECM homeostasis, and thus enriched the deposition of ECM in aged human skin in vivo. 0.4% topical ROL achieved similar results as seen with topical retinoic acid, the biologically active form of ROL, without causing noticeable signs of retinoid side effects. CONCLUSION: 0.4% topical ROL shows remarkable anti-aging effects through improvement of the homeostasis of epidermis and dermis by stimulating the proliferation of keratinocytes and endothelial cells, and activating dermal fibroblasts. These data provide evidence that 0.4% topical ROL is a promising and safe treatment to improve naturally aged human skin.
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