Is Adapalene a Retinoid?
Yes, adapalene is definitively a retinoid—specifically, a synthetic naphthoic acid derivative with retinoid-like activity that is FDA-approved for acne treatment. 1, 2
Classification and Mechanism
Adapalene is classified as a topical retinoid and is explicitly categorized alongside tretinoin, tazarotene, and trifarotene as one of the four FDA-approved topical retinoids for acne vulgaris. 1 The FDA drug label confirms adapalene as a "retinoid" agent. 2
Receptor Binding Profile
Adapalene exhibits selective binding to specific retinoic acid receptors (beta and gamma), which distinguishes it from other retinoids:
- Tretinoin binds to alpha, beta, and gamma retinoic acid receptors 1
- Adapalene and tazarotene selectively bind to beta and gamma receptors only 1
- This selective receptor binding confers slight differences in activity, tolerability, and efficacy compared to other retinoids 1
Chemical Structure
While adapalene is a retinoid, it has a distinct chemical structure as a naphthoic acid derivative rather than a classic vitamin A derivative. 3 Despite this structural difference, it maintains retinoid-like biological activity through its binding to nuclear retinoic acid receptors. 3, 4
Clinical Significance
The American Academy of Dermatology identifies retinoids, including adapalene, as the cornerstone of acne treatment because they are:
- Comedolytic (break down comedones) 1
- Anti-inflammatory 1
- Effective at resolving the precursor microcomedone lesion 1
Adapalene 0.1% gel is available over-the-counter, while higher concentrations require prescription. 1