Retinoids are the most evidence-rich ingredient group in anti-aging care. However, OTC "retinol" and prescription "tretinoin (retinoic acid)" have significant differences in mechanism and efficacy.
The retinoid conversion pathway
The form that actually works in skin is retinoic acid (tretinoin). OTC retinol must undergo two enzymatic conversion steps in the skin: retinol to retinal to retinoic acid. Conversion efficiency varies individually, with only about 5-20% ultimately converting to the active form.
OTC retinol vs prescription tretinoin
OTC retinol is formulated at 0.025-0.1%, but effective concentration is even lower after conversion. Prescription tretinoin at the same 0.025-0.1% acts directly without conversion, making it dramatically more potent. However, irritation is also stronger, with frequent redness and peeling (retinoid reaction).
Gradual increase protocol
"Gradual escalation" is the golden rule for retinoid use. Start at low concentration, then gradually increase concentration and frequency as the skin builds tolerance. Starting with twice-weekly evening use and transitioning to nightly is the standard protocol.
Bakuchiol -- a plant-based alternative
Bakuchiol is a plant-derived compound that acts on retinoic acid receptors. Similar effects to retinol (collagen promotion, wrinkle improvement) have been reported, with virtually no retinoid reaction (redness, peeling). It is gaining attention as an alternative for retinoid-sensitive skin.
References
Key peer-reviewed sources behind the scientific statements in this article.
- Dhaliwal S, Rybak I, Ellis SR, Notay M, Trivedi M, Burney W, Vaughn AR, Nguyen M, Reiter P, Bosanac S, Yan H, Foolad N, Sivamani RK. Prospective, randomized, double-blind assessment of topical bakuchiol and retinol for facial photoageing. Br J Dermatol. 2019;180(2):289-296. PubMed
- Chaudhuri RK, Bojanowski K. Bakuchiol: a retinol-like functional compound revealed by gene expression profiling and clinically proven to have anti-ageing effects. Int J Cosmet Sci. 2014;36(3):221-230. PubMed
- Zasada M, Budzisz E. Retinoids: active molecules influencing skin structure formation in cosmetic and dermatological treatments. Postepy Dermatol Alergol. 2019;36(4):392-397. PubMed