In short
Retinol turns into retinoic acid, the active form, inside human skin.
What it is1
Applied to the skin, retinol can enter it and is converted first to retinaldehyde and then to retinoic acid.
Quan T. Human Skin Aging and the Anti-Aging Properties of Retinol. Biomolecules 2023
Worth knowing2
Studies report that vitamin A and what it turns into can improve skin aged by time and sun, by stimulating new collagen and slowing its breakdown.
Quan T. Human Skin Aging and the Anti-Aging Properties of Retinol. Biomolecules 2023There is less research on how topical retinol works in living human skin than on retinoic acid.
Quan T. Human Skin Aging and the Anti-Aging Properties of Retinol. Biomolecules 2023
Sources
These pages describe what the sources say. They cannot say what is going on with your skin.
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