Vitamin A (retinol) was discovered over a century ago as a key dietary nutrient for mammalian health, and especially for the health of our eyes. (Hence the word retinol, named after our retina!)<\/p>\n
In subsequent years its mechanism and functionality, and that of its precursors and metabolites \u2014 \u00a0such as beta-carotene, retinaldehyde, and retinoic acid \u2014 have been elucidated, and the acid form was found to be the most active version in the body. In the world of skin health, all-trans retinoic acid, tretinoin, became an important prescription skin medication for treating acne and UV damage, and topical retinol became widely used in cosmetic skincare.<\/p>\n
It was not until 1987 that scientists discovered the receptor that interacts with retinoic acid, and termed it the retinoic acid receptor,<\/a> or RAR. From this discovery we learned how RARs trigger gene expression and cell differentiation and other biological process. Several variants of RARs have since been uncovered: RAR-alpha, RAR-beta, and RAR-gamma. And inn recent decades scientists have screened for other molecules, non-Vitamin A molecules, to see whether selective targeting of these receptors can improve skin health<\/p>\n New molecules that have been synthesized that powerfully target RARs, and these actives along with Vitamin A are now called retinoids. The modern synthetic retinoids such as adapalene<\/a>, tazarotene<\/a>, and trifarotene<\/a> were designed specifically for selective receptor activity, enhanced stability, and improved tolerability without relying on the traditional Vitamin A chemical structure.<\/p>\n So what is a\u00a0retinoid today? It is any kind of molecule that binds to the body\u2019s retinoic acid receptors. While\u00a0retinol, retinaldehyde, and retinoic acid are familiar first-generation Vitamin A retinoids, a true retinoid is not limited to Vitamin A ingredients, nor does it require the \u201cretin-\u201d root in its name.<\/p>\n