Retinal

Retinal (retinaldehyde) is a potent vitamin A derivative used typically around ~0.05–0.1% in cosmetics and is closer to retinoic acid in conversion steps than retinol, which increases the likelihood of erythema, burning, peeling, and barrier disruption—especially during initiation. Clinical experience and comparative tolerability data for topical retinoids show meaningful irritation is common in sensitive and eczematous populations even at standard concentrations, and cumulative irritation is amplified when paired with acids, benzoyl peroxide, or frequent cleansing. Given its active potency and predictable retinoid dermatitis risk in compromised skin, it warrants a high irritancy score with careful introduction and buffering. Safety Notes: In consumer leave-on skincare, retinal (retinaldehyde) is commonly marketed at low levels around 0.01% and can be found as low as ~0.005% in sensitive-skin or “starter” serums/creams, sometimes due to dilution from encapsulated/delivery-complex actives. High-strength OTC products marketed specifically as intensive retinal treatments are observed up to ~0.2% retinal; above this is uncommon in mass-market retail due to irritation risk and stability/oxidation constraints. Retinal is essentially used in leave-on products (serums/creams) rather than rinse-off formats because contact time is required for efficacy.

Suitability