Retinol
Also known as: Vitamin A, Vitamin A1, Retinyl alcohol
Description
Retinol is an over-the-counter retinoid and a precursor to retinoic acid (tretinoin). It must be converted in the skin through two enzymatic steps — first to retinaldehyde, then to retinoic acid — to exert its biological effects. Though less potent than prescription retinoids, it is widely used for anti-aging and acne due to its accessibility and generally milder side-effect profile.
Mechanism of Action
After topical application, retinol is converted to retinaldehyde by alcohol dehydrogenases, then to all-trans retinoic acid by retinaldehyde dehydrogenases. The active retinoic acid binds nuclear RAR/RXR receptors, modulating gene expression to increase cell turnover, stimulate collagen synthesis, and reduce matrix metalloproteinase activity. The multi-step conversion results in a slower, more sustained release of active retinoic acid compared to direct tretinoin application.
Indications
- Fine lines and wrinkles
- Photoaging
- Uneven skin tone
- Mild to moderate acne
- Enlarged pores
- Rough skin texture
Available Concentrations
Side Effects
- Dryness
- Peeling
- Erythema
- Initial purging
- Photosensitivity
- Irritation (generally less than tretinoin)
Contraindications
- Pregnancy
- Breastfeeding
- Eczematous or broken skin
- Concurrent use with other strong exfoliants (caution)
Pregnancy Category
X (retinoids as a class)