Adapalene, sold under the brand name Differin among others, is a third-generation topical retinoid primarily used in the treatment of mild-moderate acne, and is also used off-label to treat keratosis pilaris as well as other skin conditions.

[7] Due to its effects on keratinocyte proliferation and differentiation, adapalene is superior to tretinoin for the treatment of comedonal acne and is often used as a first-line agent.

Other non-FDA approved indications that have been reported in the literature include treatment of warts, molluscum contagiosum, Darier's disease, photoaging, pigmentary disorders, actinic keratoses and alopecia areata.

[18] Unlike the retinoid tretinoin (Retin-A), adapalene has also been shown to retain its efficacy when applied at the same time as benzoyl peroxide due to its more stable chemical structure.

[3] Controlled trials of chronic users of adapalene have found drug levels in the patients' plasma to be 0.25 ng/mL.

[7][13][20] Adapalene is also regarded as an anti-inflammatory agent, as it suppresses the inflammatory response stimulated by the presence of Cutibacterium acnes,[7] and inhibits both lipoxygenase activity and the oxidative metabolism of arachidonic acid into prostaglandins.

[23] Within the initial period of treatment, skin can become red, irritated, dry and may burn or itch from retinoid application; however, this tends to resolve within four weeks with once a day use.

In human, mouse, rat, rabbit, and dog cultured hepatocytes, metabolism appears to affect the methoxybenzene moiety but remains incompletely characterized.

[26] A study has concluded that adapalene can be used to treat plantar warts and may help clear lesions faster than cryotherapy.