Tretinoin (retinoic acid) is the retinoid that has the best evidence behind it. This is the retinoid that is approved by the FDA for treatment of photodamage and acne. If your SkinSize dictates you could benefit from a retinoid then it is important to use one that will work. Retinol is a common cosmeceutical found on off-the shelf products that skincare companies know will be easier to use – but that is at the expense of effectiveness. Tretinoin is at least 20 times, and anything up to 100 times more powerful than retinol.
Tretinoin will change how a cell functions, it speeds up the turnover of older cells and encourages newer skin cells to divide more rapidly and build up the layers of the epidermis, thickening it through cell proliferation at the top level. It also increases the production of hyaluronic acid to keep the skin more plump. It can stimulate collagen production and importantly inhibit the breakdown of collagen. Tretinoin is also important to reduce inflammatory pathways in the skin that can contribute to acne and rosacea.