Tretinoin (topical retinoid)

Also known as: all-trans retinoic acid, Retin-A (brand), Renova (brand)

Hair RestoreDermatology

In plain English

Tretinoin is a prescription vitamin-A cream used for acne, sun-damaged/aging skin, and dark spots, and it is added to some hair formulas to help other ingredients absorb. It speeds skin-cell turnover, unclogs pores, and stimulates collagen. Expect dryness, peeling, and redness early on; results build over months. It should not be used in pregnancy.

The science

Tretinoin binds nuclear retinoic acid receptors (RAR/RXR heterodimers), altering gene transcription to normalize follicular keratinization, increase epidermal turnover, and stimulate collagen synthesis while inhibiting UV-induced matrix metalloproteinases. Multicenter studies established its efficacy for photoaging and acne; it is a cornerstone topical retinoid and is frequently combined with hydroquinone and a corticosteroid (Kligman-type formulas) for melasma.

References

• Mukherjee S et al., Clin Interv Aging 2006 (retinoids in skin aging)
• Anwar AI et al., efficacy of topical treatments in mild-moderate acne (systematic review), Cureus 2024