Brand name: Retin-A
International name: Tretinoin

Pharmacological action:
Retin-A - a natural metabolite of retinol, it breaks gene expression stimulating changes of protein synthesis. It passes through a cell membrane and forms complexes with specific cytoplasmic receptors that penetrate into the cell nucleus, joining with DNA. Tretinoin inhibits gene transcription factor (AP-I), which helps to reducing or stopping the synthesis of metalloproteinases and leveling the negative action of sunlight on the skin (including hyperpigmentation). Tretinoin reduces the melanin content in the epidermis. The induction of transcription leads to an increased number of epithelial cells in a state of mitosis, which helps to reinforcement of proliferation processes in the upper dermis and epithelium regeneration; it reduces a cell adhesion taking part in an acne formation, it also prevents keratic plug and new blackheads formation. There are facts that tretinoin inhibits a keratin synthesis, promotes a hair growth (slightly) and has a weak anticancer effect.