Tretinoin also known as retinoic acid comes from Vitamin A is recognised as the gold standard of anti-ageing ingredients , as it can have profound beneficial effect on the stratum corneum layer and deeper layers of the skin. By regulating cellular functions, keratin becomes softer and the stratum corneum becomes smooth and compact. These effects can last for up to 4 months, even when the use of the product has ceased.
Retinoids and Skin Ageing - https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2699641/
Initially tretinoin dehydrates the outer surface of the stratum corneum while keeping the dermosomes intact. (The function of desmosomes is to adhere cells together). This leads to a rapid , coarse exfoliation and shedding of an attached group of cells, the opposite to what happens when AHA's are applied to skin - where individual cells are shed.
Topical tretinoin has shown to be an effective in improving signs of ageing both intrinsic and extrinsic, incl fine lines, hyperpigmentation and wrinkles. The concentration of tretinion has a direct correlation with its beneficial activity on the skin, the higher the concentration, the deeper and more potent its effect. Concentrations of 0.025% benefit the epidermis whereas higher concentrations 0.05% to 0.1% have both epidermal and dermal effects. Carriers also have an impact on the potency, Moisturising components added to the formulation weaken the action and the benefits of tretinoin. Therapeutic use of tretinoin is usually for 18 weeks.
In the dermis tretinoin repairs damaged keratinocytes , increase basal call mitosis, restores natural hydration, and increases epidermal thickness.
In the dermis tretinoin increases elastin fibres , and angiogenesis (Angiogenesis is the growth of blood vessels from the existing vasculature) and glycosaminoglcan deposition. Effective and Sustained Delivery of Hydrophobic Retinoids to Photoreceptors https://pubmed.ncbi.nlm.nih.gov/8345226/
Initiation of tretinoin treatment is frequently associated with retinoid dermatitis, characterised by erythema, dry skin, burning sensation, and desquamation. In addition, because of thinning of the stratum corneum, tretinoin makes the skin more sensitive to the sun. The severity of retinoid dryness/ irritation depends on skin sensitivity, concentration and formulation of retinoic acid, and frequency of application. Retinoic acid is normally hydrophobic, which means that it repels water with minimal penetration through the stratum corneum layer of the epidermis. As the retinoic acid is trapped in the stratum corneum, it gradually induces irritation and inflammation associated with retinoid dermatitis.
Retinoids in the treatment of skin ageing: an overview of clinical efficacy and safetyhttps://www.ncbi.nlm.nih.gov/pmc/articles/PMC3061517/
Retinol is often used as a maintenance for Tretinoin as it does not have the same levels of irritation and patients are able to build up a tolerance level unlike tretinoin.
Tretinoin is a prescription medication.
Retinol, like tretinoin is a Vitamin A derivative. They are the most studied and have he most data supporting their efficacy in skincare.
Within the skin, retinol is first oxidised into retinaldehyde and then to tretinoin, the biologically active form of Vitamin A.
Topical retinol leads to a decrease in the appearance of wrinkles through the increased production of glycosaminoglycans - which retain substantial amounts of collagen and water.
Despite despite demonstrating the same beneficial effects as tretinoin, topical retinol produces only minimal signs of irritation, mostly seen as the skin acclimatises to the ingredient. Retinol is approximately 20 times less potent than tretinoin. Retinol at a 1% concentration is approximately equal to a 0% to 0.5%concentration of tretinoin.
With SkinCeutical retinols once you get past the initial irritation and peeling, the results are very often when combined with the correct routine, truly spectacular.
Results; skin is clearer, smoother with less noticeable fine lines and wrinkles.
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